Category: Energy use

And Now, Your Feature Presentation

I’ve been gradually building up a summary of the main features that I plan to include in the Little Rental House.  Some of these will go in with the first build; others might be “nice-to-haves” that get added once the home is actually ready for occupancy.

  • Accessible
    • ADA-compliant parking space
    • ADA-compliant bathroom, kitchen, living areas
    • ADA-compliant entrance ramps, etc.
  • Efficient resource use for heating and cooling
    • Walls, ceiling, and floor all insulated to better than R-40.
    • Double (or maybe triple) glazed windows for heat retention.
    • Heated with air-source heat pump to minimize power required.
    • Heat-recovery ventilator to provide fresh air with minimum heat loss.
    • Hot water heating inside heated space (reduces heat loss)
    • Drain water heat recovery unit
  • Minimum water footprint
    • Rainwater collection with filtration and UV sterilization
    • Downcycling of greywater for toilet flushing
  • Minimum power requirements
    • Low-voltage LED lighting used throughout to save power (< 0.25kWh/day)
    • DC refrigerator (< 0.7kWh/day)
    • Direct outlets for DC appliances (24V, 5V USB)
    • Two stage water heating with ultra-insulated storage (30 gal, est. < 0.5kWh/day) plus on demand system for large volume use (AC only)
    • Water pumping using low power, low voltage DC pumps (< 0.1kWh/day including sterilization)
    • Heat recovery from waste water (bathtub, clothes washer, sinks)
  • Grid-flexible solar power generation
    • Battery storage (about 10 kWh) for approximately 6 days including hot water, up to 2 days with constant heating.
    • Online inverter provides whole-house “uninterruptible” power supply

The City of Ithaca and Town of Ithaca are working on a new joint “energy code supplement” to encourage green building.  New construction should get a minimum of 6 “points” in their system.  My rough calculation for the proposed home is 11 points:

  • EE1: air source heat pump = 3 points
  • AI1: smaller building size = 2 points (under 1120 sq ft)
  • AI2: heating system in heated space = 1 point
  • AI5: modest window-to-wall ratio (13%) = 1 point
  • RE1: on-site renewable electric = 3 points (2350 kWh/year / 648 sf > 3.6)
  • OP4: meet NYStred Code-2020 Version 1.0 = 2 points (maybe, complex to evaluate)

Wow, I’m Floored!

For the last couple of weeks it has been “damn the winter weather, full speed ahead!”  And somewhat to my surprise, I managed to get the floor panels I designed (and wrote about here) completed.  Apparently after repeated exposures, my hands finally got used to working in 37°F (2.8°C) weather, and I didn’t feel cold any longer.  My ears were protected by 3M™ WorkTunes™ headphones, which may have been the single best tool investment I have yet made on this project.  Certainly the most consistently utilized, particularly with Spotify keeping my ears happy and not merely warm.

A big ($3000) order of materials was delivered in late October, and I immediately started trying to get the flooring in place.  Zephyr was intrigued.

Curious cat is curious

At first things went pretty quickly.

However, my birthday party happened just a day or two into getting the materials, so it was almost November before I really got going.  Below you can see the bracing ready for the 2x4s to come in above the PIR foam board, and the 2×6’s used for every third span (west side) and for all of the 7′ spans (east side).

Here is some of the PIR foam board in place, 2×4’s across the top and on the braces, spray foamed along edges of PIR, as well as the first batt of rockwool.

And finally here is what it looks like with all the rockwool in place.

Then I started to get the actual subfloor laid on top.  Unfortunately, not very long into this we had our first 4″ snowfall, and thereafter I was spending a lot of time with the shop-vac removing the snow and water that was stuck inside various cavities (either on top of the PIR board, or on the PT plywood bottom layer where the PIR board was not yet laid).  Furthermore, laying the tongue-and-groove subflooring with the appropriate staggered (and thus, diagonal) pattern turned out to be extremely time consuming.

It’s probably worth sharing that the necessary tools for this are one (or more) sacrificial 2×4’s and a sledgehammer.  You lay the 2×4 against the edge of the subfloor plywood (best if it’s the groove side) and whack the crap out of it to get the plywood to move across the glue and into place.  I shattered one 2×4 along the way and beat another one beyond the point of further usefulness.  Also, on occasion, you may want wood shims (used to force the tongue up into the groove) or a wonderbar weighted down with a heavy piece of PT lumber (used to force the groove plywood down onto the tongue).  Or, you could do this with more than one person, in which case, you get someone to stand on the edge to keep it aligned while you whack the 2×4.  This is definitely one of those “better done with a team” jobs.

But, in the end, I managed to get it all in place.  I still want to come back and add the house-wrap to the remaining 2/3 of the floor, to keep water out over the winter, but at least the main job is now complete!

 

Was it worth it to do all that extra complex framing for the 10% improvement in insulation?  I’m not sure – maybe not.  I’m estimating that adds up to maybe 85 BTU/hr or 25W of heating saved, whereas the remaining total loss through the floor is perhaps 875 BTU/hr or 256W.  The R-41 SIPs would have been closer to 553 BTU/hr for a savings of 94W.  (All these numbers may be lower if the equilibrium temperature in the basement is higher.)  But I learned a lot of interesting things along the way.

When It Rains, Do Like The Romans

I may have my idioms mixed up, but rainwater catchment goes back a very very long time in history.  Although it certainly goes back to the Indus Valley, in some sense it probably is prehistoric.  The Romans, however, applied their engineering skills to the task (along with the famous aqueducts), and made some significant innovations.

In this post I’m going to talk in some depth about my plans for rainwater harvesting, which has the two-fold purpose of demonstrating some interesting sustainability techniques, plus also reducing the ecological footprint of the construction and residence.  This post is also an experiment in a different writing style – I’m going to explain not only the design outcome, but many of my steps (and missteps) along the way.  A lot of people have written up their finished rainwater systems; it seems less common for people to talk about the ideas they have considered or the attempts they have made, which they later ruled out.  I hope this provides some interesting fodder for people designing their own systems.

Going back to the ecological footprint, there are three factors I wanted to consider: stormwater runoff, consumption of limited groundwater, and exposure to the potentially toxic chemical byproducts.

  1.  One of the major considerations for new development (at least in NY) is the “stormwater pollution prevention plan” or SWPPP.  The addition of impermeable surfaces (like roofs and roads) interferes with the normal absorption of water into the ground, and potentially causes significant additional runoff to arrive in streams.  Along with this runoff are various types of pollution that would be found on the surface, ranging from silt to fertilizer to motor oil from cars.  To the extent that we can minimize the amount of runoff, we can reduce the magnitude of the required catchment areas and reduce the amount of material deposited there.
  2. The sole source for drinking water in our community is groundwater (wells).  We have a pair of high-performing artesian wells that dip into a local aquifer that was recently studied extensively by the USGS.  (One of the wells was even part of their testing.)  However, as more homes are built both in our community and elsewhere in the town, the demand on this aquifer will increase, and it’s possible that at some point it will have trouble being replenished quickly enough to supply all of the needs.  Thus, having an independent source of water (rainwater) will both reduce dependence on, but also demand on this aquifer.
  3. Because our community exceeds the minimum size set out by the EPA for a “community public water system”, we are required to use “approved” chlorine treatment in our community water.  Many people respond badly to the chlorinated water and are filtering it back out at their own homes.  Even the CDC is now questioning some of the potential health effects of the by-products of chlorination.  By using rainwater and then not sending it underground, it should be legal to use filtration combined with UV sterilization (which is actually more effective than chlorine against cryptosporidium and giardia) to supply potable water to the home.  (The effort to get this approved in Tompkins County NY was led by a couple of intrepid “Earthship” homebuilders, for which I’m very grateful.)

For me the first logical step in thinking about rainwater is understanding rainfall conditions in our area.  So I created a rainwater calculator that utilizes raw data from the local weather station month-by-month over ten years.  Later, I realized that the effects of averaging over month-by-month data really prevented me from understanding important parts of the system, so after some digging for a reasonably trustworthy data source, I shifted to a model based on day-by-day data.  Even that has some limitations I don’t really like, but I was not able to find an hour-by-hour rainfall source that I could trust and match up with the seemingly reasonable daily and monthly data.  I’ve used these data to come up with an estimate of the average rainfall, to look at the amount stored over time, to understand how the amount of storage would impact both full and empty conditions, etc.

Basic Operational Features

First, let me explain some of the principles at play here.  I’m going to shamelessly lift some images from the Texas Manual on Rainwater Harvesting, one of the widely-cited references on the topic.  These steps are:

  • Rainfall – what are the regional properties of rainfall relevant to the design
  • Catchment – how is the water collected; how much area; relation to rainfall
  • Leaf filters – removing large objects such as leaves from rainwater
  • First Flush – cleaning sediment deposited on roof during dry intervals
  • Prefilter – removing smaller objects which might clog storage tanks
  • Storage – bulk water storage volume
  • Pressurization – bringing stored water up to usable pressure
  • Postfilter – remove remaining small particles that interfere with treatment
  • Treatment – making water safe to drink

The process for designing has been somewhat iterative.  For example, I first looked at the gross rainfall numbers, catchment area, and storage to get a ballpark idea of how much storage was likely to be required.  Then I later had to fine-tune these numbers based on expectations for filtering losses, greywater reuse, etc.  As I describe the work below, I’m working from the high level considerations down to the details.

Just as a note, I’m going to use some abbreviations below so I don’t have to keep writing out complicated units: gal = gallons, sf = square feet, gpd = gallons per day, gpm = gallons per minute.

Catchment and Storage

First, consider the roof footprint or “catchment area.”  Except in the case of a flat horizontal roof, this area is always less than the area of actual roof material.  Using this number doesn’t really account for unique aspects of the weather (such as prevailing wind direction) or the site (trees blocking rainfall or wind) but it’s still the best general approximation for how to convert “inches of rainfall” into “gallons collected” – specifically, 0.623gal of water for every square foot of area.  In my case, I began work using the slightly conservative estimate of the house footprint (648sf) rather than the roof, which will have some additional overhang (giving perhaps an extra 16%, or 754sf).  The smaller number gets me 404gal per inch of rain.

By using my modelling spreadsheet, I can see that he roof is collecting on average 43gpd given our local rainfall conditions, and that is cut down to 37gpd by some of the filtering considerations below.  (Some more is lost when the storage capacity is full, but we’ll talk about that in a bit.)

That covers the input (production) side.  However, in order to effectively simulate performance around the storage tanks, we also need to measure the output: water consumption.  Guesstimating water consumption is pretty difficult, particularly since I don’t even know who is going to be living in the home.  One could use anything from single occupancy up to a reasonable (by residential code) limit of 4 residents.

Because of my involvement with our Infrastructure Committee, I happen to have data that says that the average use in our community, measured as a function of the number of bedrooms, is about 38gpd/bedroom.1  Given that this is a 2-bedroom house, that would nominally mean 76gpd, corresponding to 4-person occupancy.

However, I’m going to adjust my estimates assuming that we’re able to implement greywater recycling for toilet flushing.  (It is easy to buy a simple version like SinkPositive that just allows you to wash your hands and uses that to refill the toilet tank, but I want something that works with an accessible sink and isn’t limited to just handwashing water.)  Toilets flushing is one of the largest single contributors to home water use, about 27% on average in the US.  Even using estimates for low-flush toilets rather than the less efficient ones many people still use, it is easy to account for 25gpd (32% of our 76gpd).  So let’s take this 25gpd, arriving at 51gpd for all other uses, for 4-person occupancy.  For 2-person occupancy we’ll just halve the number.

Hopefully it’s fairly obvious that the relationship between production and consumption is the most important aspect of system performance.  If you’re collecting only 37gpd on average, and using 51gpd on average, you’re not collecting enough water.  If you’re collecting 37gpd and using only 25gpd, you’ve got a surplus.  Storage helps at times, but it won’t change the overall picture, as shown in the graph below.2  With two people, we’re overflowing any reasonable amount of storage ~30% of the time.  With four people, we have a shortfall with similar regularity.  This is a direct reflection of the collection capacity of the roof. 

 

 

In the long run, one obvious way to address this is simply to increase the catchment area.  If we were, for example, 35% short, we could add another ~225sf of rainwater collection area.3 For this reason, I’m imagining that I may use a ground-mounted solar array, in part to increase the potential area for rainwater catchment.

So in essence, with the current roof area, the system right now is sized for what you might consider an average 3-person occupancy.  We will just work with this starting point and assume that either (a) the residents limit their water usage to what can be harvested from rainwater; or (b) the residents don’t mind using community water when they run out.  Of course, if you make those assumptions, then by definition you can’t compute anything interesting about storage.  We do want the system to have some storage, so for that purpose we’ll consider the 3-occupant, 37gpd model, i.e. where production and consumption are roughly similar.

We also need to consider pragmatic limitations: the basement entrance won’t allow us to install or replace tanks larger than about 47″ in diameter; the ceiling limits us to tanks no higher than 92″ (and, if we want to be able to get any access to the top, probably more like 80″).  However, we can install multiple tanks, and interconnect them for more storage.  Each tank is adding system cost, but if they’re all ordered at once some of those costs (like delivery charges) will be constant.  My current working selection is a Rotoplas RP-590283 tank, which holds 300gal and is at present selling for about $250.  These are 36″ in diameter and 76″ high, so they are easy enough to get into the basement.  This means our storage capacity will be sized in 300gal increments.

Based on the graph above, you can see that more storage always helps, unless you’ve only got 2 occupants.  4 tanks (1200 gallons) will mean our 2-occupant family is only using community water about 1% of the time, and when starting from full tanks they can weather a 48-day total dry spell.4  For higher consumption, there’s always a return on storage, but even with just 3 occupants, reaching this 1% level would require more than 7000 gallons of storage, which is just silly.

For the present, I am satisfied with a 1500 gallon system capacity which will be more than enough for 2 occupants, leave 3 occupants on community water about 13% of the time, 4 occupants about 30% of the time.  Let us now turn to some of the more subtle design aspects.

Prefiltering and First Flush

The enameled steel roof that I will be using is pretty much ideal for potable water collection.  It doesn’t leach out much in the way of undesirable chemicals, like you might see from an asphalt shingle, plastic, or galvanized roofing material.  It doesn’t give off particles of its own, and it doesn’t particularly trap particles.  Also, since there are no trees of any size within hundreds of feet of the house, I don’t have to worry much about leaves.

Nevertheless, it’s helpful to put screen filters into the system to catch anything large that might be coming through.  Although these can go over the gutters themselves, or be put directly at the downspout entrance, that means needing a ladder to clean them, so I expect that I will opt for an inline filter basket in the downspout.  I haven’t definitively decided on a model, but some that I am considering are the AquaBarrel Slim Line at $50 or the Leaf Eater Ultra at $40.  Some of the cheaper products (Amerimax FlexGrate, $6) are not enclosed and seem like they would be too susceptible to letting as many things (dust, bugs, etc.) in than they keep out.  There are also more expensive products (WISY FS305, for $400 or more) that are pretty and made out of stainless steel, but which are likely overkill if there is additional filtration in the system, and needlessly push up the system cost.

For additional filtration, I plan on using a “first-flush diverter” to eliminate some of the fine particulates (e.g. summertime pollen and wintertime wood ash) so that the incoming water is cleaner.  The way this works is to assume that any time it hasn’t rained recently, the roof is dirty; based on this assumption, the first small amount of rain is shunted off to a holding chamber which captures the sediment along with that water.  When the holding chamber is full, the (now cleaner) water is directed into storage.  Typical recommendations are “13 to 49 gallons per 1,000 square feet.”5  I’m starting with a mid-range number of 23gal/1000sf, which roughly corresponds to another number I have seen, which is the first millimeter of rain.  Or, simply put, 15gal.

Now it turns out that if we have a rain of 1mm or less, then it all goes into the first-flush system – which based on daily rainfall data happens for about 27.5% of the rainy days.  On the other hand, because many rainfalls are heavy, I only lose a total of about 14% of the rainwater to the first-flush system.  (In fact, if we use the 2-occupant model, I actually lose more water – over 28% – due to the system being full and not having capacity for more water to be stored!)

You can buy a first-flush diverter, but you can also build one, which turns out to be pretty simple.  There are a number of ways, but one of the simplest (shown here, again from TMRH) is simply a standpipe with a “weep hole.”  The sediment falls to the bottom of the standpipe; when the pipe is full, the incoming water can’t go into the standpipe any longer, and gets directed to storage.  In this partial cut-away drawing, the “weep hole” is actually replaced by an adjustable valve (“hose bibb drip”) but that isn’t strictly necessary.  So one can calculate the capacity based on the number of gallons that fit into a given diameter and length of pipe.

I tried to find a nice table for this, and the best I could come up with was this chart from Wake County, North Carolina.  The most readily available pipe is usually “Schedule 40” rigid PVC pipe.6  I made up a quick table for practical sizes that one might consider.  It is interesting that there’s a sweet spot in price per gallon for 6″ pipe.  The problem, of course, is that if you are trying to fit 15 gallons of storage into a vertical pipe in an 8′ high room, you can’t fit it into a 6″ pipe.  The 8″ pipe, on the other hand, will come in a little under 6′.

Nominal SizeGallons/Ft$/Ft$/Gallon
3" Sch 400.384$1.83$4.76
4" Sch 400.661$2.18$3.30
6" Sch 401.5$4.02$2.68
8" Sch 402.6$11.70$4.50

So imagine that we have that piece taken care of, what comes next?  Well, ideally we want to filter out any particles that still make it through.  Unfortunately, we don’t have a huge amount of pressure so most of the conventional filters that are used for city water probably won’t work.  Another filter that is sometimes used for rainwater is a “slow sand filter“, which is a biologically active filter that takes out both particulates and microorganisms that may be coming in.  However, true to their name those operate extremely slowly (gallons/hr rather than gallons/min) so they would need to have a lot of capacity to avoid losing useful rainwater.   There are, however, some filters that are specifically made for rainwater catchment.

The filter I’m most likely to go with is the Maelstrom which is made in Australia – a country where rainwater collection has become a bit of an art form.  The advantages of this filter are that it filters down to 180 microns (0.18mm) even though it can handle flow rates of 80 gallons per minute with minimal losses.  (Some people even use the Maelstrom as a direct filter for the downspout water, but it seems like it would be more difficult to clean so keeping the larger particles out should make it require less service.)  Also, it works with standard 4″ pipes, and can be mounted in any of several convenient ways including directly at the top of a tank.  While it would be great to get to 30 microns or less, we’ll save that for after the storage tanks where the water is pressurized.

Pressurization

In the storage tanks, the only pressure the water is under is its own weight – an 8′ high column of water gives about 3.5psi, and our tanks won’t even be that tall.  We need to increase the pressure to the level where appliances expecting city water (30-40psi) will operate normally.  If we were trying to handle large volumes of water, we would potentially need a big pump for this, and that means a lot of power.  However, if we have enough intermediate storage, we can potentially use a lower flow rate “slow pump” and thus avoid a big power draw.

It turns out this set of requirements exactly matches something that is widely available: fresh water pumps for recreational vehicles.  Pumps like the Shurflo 4048 from Pentair deliver exactly what we’re looking for: flow rates up to 4gpm, pressures up to 55psi, and operation from 12V at less than 10A.  We then need to couple this with a relatively large pressure tank to give the pump enough time to get the pressure back up for normal usage.  A Pentair WM25B, Goulds V260, or Amtrol WX-255D each provide 25-30 gallons while keeping the pressure between 30 and 50psi.

Postfilter and Treatment

We’re ready to make this water drinkable.  Because the water is not going underground again after treatment (for which the only approved solution in NY state would be chlorination), we have a number of options.  The most appealing, because of the lack of chemical residue, is UV treatment.  It wasn’t clear to me how much power this was going to take, but it turns out that it’s the equivalent of a light bulb.  One of the critical things for UV treatment, however, is ensuring that there is no sediment in the water that could block the UV light from treating it effectively.  A convenient solution to this is a combined sediment filter and UV unit.

While I was originally looking at Viqua (first some of their high-volume units such as VH410M and then later at S2Q-P/12VDC), none of these included a sediment filter.  I found the UV006 unit by PuraUV which includes the sediment filter, supports a higher flow rate (8-10gpm), and like the S2Q-P/12VDC can be operated from 12V for off-grid applications.  This draws only 22W – it requires less power than the pump!

To save myself from having to replace the filters in the PuraUV too often, I also plan to include one additional filter, a Rusco 15 micron spin-down filter.  The nice thing about these filters is that they can be cleaned simply by opening a “flush valve”, and the pressure of the water itself washes the accumulated grit off the filter.  Although they may need to be replaced eventually, they can be reused thousands of times rather than needing a replacement filter every 6 months.

Community Water Backup

There’s one step I’ve left off above, because it seems like it would confuse things, which the the backup for using community water when we run out of rainwater. I considered two slightly different ways to approach this: adding the backup water into the storage tanks, or switching the backup water on after the treatment system.  (Since this water is already chlorinated, it doesn’t need to be treated again.)

The advantages of going into the storage tanks are:

  1. The solution can be purely mechanical – like the valve on your toilet tank, a float valve can be used to turn this water supply on only when the level in the tanks is so low that they’re considered “empty.”
  2. The chlorinated water can effectively disinfect all the subsequent portions of the system, if there is every any sort of issue.
  3. A minimum level of water can be maintained which is always available with solar power, even if grid power is out.
  4. An “air gap” can be installed to prevent any chance of rainwater backflowing into the community system.

The advantages of switching the water on after the treatment system are:

  1. The pressure pump and UV system can be shut down when we’re out of rainwater, drawing no power and saving wear and tear.
  2. The backup water can be used to supply additional pressure if the rainwater system is not keeping up.
  3. Easier to integrate rainwater system after-the-fact.

Probably based entirely on the last reason in the list, I expect to start out with the house plumbing directly connected to the community water supply, and then as time and money allow, add in the rainwater system.  Then, if it appears at that point like the direct-to-storage-tank solution would be better, I can adjust the inlet plumbing to accommodate that.

Conclusion

Collecting a little rainwater for watering your garden is something anyone can do.  It is easy and certainly worthwhile.  In contrast, attempting to supply water to an entire household based entirely on rainwater, while making this more-or-rainwater_calculatorless invisible to a “western, developed-world” homeowner who expects never to think about where their water comes from, is an undertaking of an entirely different scale.  I hope that the data, tools, components, and overall thought process that I’ve shared here will make it easier for others to pursue similar projects in the future.

P.S. The complementary conjugate idiom, “When in Rome, it pours,” is probably somewhat less valid.  Rome gets less rainfall than Ithaca, averaging about 31 inches/year.

  1. This arcane way of measuring is what is utilized by the NY Department of Environmental Conservation in determining how to size a septic system.  But it gives us a hand-waving first approximation. ↩
  2.  The orange/green/blue lines represent a 4-, 3-, and 2-person occupancies (51, 37, 25gpd) respectively.  The solid lines represent the system shortfalls at a range of storage capacities; the dashed lines represent water collection that exceeds storage capacity (i.e. overflows). ↩
  3. As noted above, if I add to the house footprint 1′ roof overhangs on all sides, this increases the system capacity by 16%, and we’re now just 120sf short. ↩
  4. The NY drought of 2016 is part of the main daily dataset I am using.  Our intrepid rain-drinking family of 2 might still have gotten 899gal (more than half of their water) from rainwater in June and July, taken a net 553gal from storage, and required only 108gal from the community supply.  Their longest dry spell would have been March 2015 when they would have gone for 19 days on primarily community water. ↩
  5.  Texas Manual on Rainwater Harvesting ↩
  6. I won’t digress right now into explaining what “Schedule 40” means… just take it as “the white pipe that doesn’t say ‘not for pressure use’.” ↩

Deep Thoughts

No, not a Jack Handey reference, although I did find those amusing at one time.

I’m here to talk about my basement.  Why on (or more accurately, under) earth would I put thousands of extra dollars into a basement which doesn’t even provide living space?  It turns out that there are a host of reasons, many of which are quantifiable in dollar terms.

  1. Rainwater storage: $5,000 saved without direct burial.
    There are conventional water storage tanks which are designed to rest on a floor, and there are direct-burial “cisterns”. Even though both can be found in the price range of $0.70 to $1.20 per gallon, the cisterns tend to be on the higher end of the price range.  For 1500 gallons of water storage, a difference of $0.50/gallon is $750.  However, this is the least of the concerns.  A direct-burial cistern needs tank heaters if the frost line is below the level of the tank (and of course, it is here1).  These would obviously consume precious energy.  Then, there’s the excavation cost (assume a tank height of 48″, buried at maximum depth of 36″, in a 15’x10′ hole, excavated 8′ deep and then partially backfilled with compacted sand) which could add another $3,000.  Plus the materials for backfilling, perhaps another $1,200.
  2. Doing plumbing labor myself: $4,000 saved with basement.
    When one is doing plumbing work in a slab, one is literally setting into concrete the pipes and drains.  Any mistake (due to inexperience, or a design change) becomes extremely difficult to rectify after the fact.  I think it is fair to assume that being able to do the plumbing entirely myself will save $4,000.  (Typical plumbing costs for the reference homes were $8,500 to $9,200.)2
  3. Reduced heating costs relative to slab-on-grade: $150 per year
    By using the super-insulated SIP flooring over a relatively constant basement temperature, we’re able to save significant energy costs for heating and also require a smaller heating system. 3
  4. Solar storage battery lifetime extension: $600 per 10 years.
    Lead-acid batteries have a significantly extended lifetime and better retention of stored energy (albeit at a somewhat reduced capacity) if they are kept at lower temperatures.  Assuming a $2,000 battery array with a basic lifetime of 10 years, the loss in capacity might require a 10% increase in size, but the lifetime might be extended to 16 years.  Obviously the larger the battery array, the greater the impact, and this is an ongoing reduction in maintenance costs rather than a significant difference in initial cost.  The lifetime of electronics such as inverters and chargers is generally better at lower temperatures as well.
  5. Space for drain water heat recovery: $100 per year
    With a ground floor bathroom, it would be difficult to install a drain water heat recovery system.  This system can provide significant savings in the energy required to supply the home with hot water.
  6. Space for solar batteries and inverters.
    Although this doesn’t have a calculable direct cost impact, the fact that these large items don’t take up space in the home means that the living space doesn’t need to be increased to compensate.
  7. Space for greywater recycling.
    Again, this has no easily measurable cost impact.  However, because the toilet by itself uses over a quarter of the water in a typical US household, reuse of greywater from other sources for toilet flushing can dramatically extend the capacity of rainwater storage, allowing for a smaller system or better performance of the same-sized system (fewer “dry spells” that must be sourced from groundwater supplies).
  8. Space for rainwater first-flush system.
    Probably the greatest source of contaminants in rainwater comes from dust that collects on the roof between rain storms.  A “first-flush” system which discards the first 0.1″ of rain during each storm allows these contaminants to be washed away, providing much better water purity at the input.  Meanwhile, the flushed water can be routed directly to the greywater storage.  Such a system could be installed outdoors, but then it would be susceptible to freezing and potentially need to be disconnected during the winter time.  By implementing it inside the basement, it can be easily interconnected, easily maintained, and protected from freezing all at once.

So on the assumption that I have the house for 10 years, the basement is saving me on the order of $12,000.  Although I don’t have a direct way of comparing, this is comparable to the cost of the basement, and it also provides a number of non-monetary benefits listed above.

So, we go deep.

  1. “Frost depth for a normal winter in the northeast is usually no more than 4 feet, so traditionally pipes are buried at 4 or 4 1/2 feet (5 ft for the main).  With only one day in February above freezing so far, the frost line has gone well below normal.” ↩
  2. Electrical work might be similar, except that in general very little of it needs to be done in the slab. ↩
  3. Detailed calculation: Slab-on-grade, 102′ perimeter, 0.5 BTU/(hr-ft-°F), 24 hours/day,  6803 degree-days, adjusted to 8628 70°F-degree-days, gives about 10.6e6 BTU/yr.  SIP floor, 648 sqft, (70-50)=20°F temperature difference for comparability, R-41 SIPs, gives 361 BTU/hr or 2.8e6 BTU/yr.  Assuming a heat pump at $0.14/kWh, this difference is about $156/year. ↩

Foundational Beliefs

As I so often seem to do, I’m leading off with a pun.  I want to write about the principles that are guiding the Little Rental House project, and the principles that I’m hoping to apply in writing about it.  At the same time, I’m in the process of getting quotations for the foundation, so I intend to update you on that as well.

Principles

Transparency

My wife Raederle has observed that as we have become more open about sexuality, money has remained one of our greatest taboos.  In writing about this house construction project, I’d like to work on breaking down that barrier and start talking about some of the relevant financial issues, including:

To this end, I intend to post my a priori budget, along with an explanation of what it is based on, so that we can look at a before-and-after comparison and talk about where the estimates were out of line, and why.

I will also be posting about the economics of rental homes and how this is part of a transitional strategy toward retirement.

Passive-Level Energy Use

The community that I live in refers to itself as an “eco-village,” and accordingly all of the homes here have been built to extremely high standards in terms of both lifetime energy efficiency and the use of local materials and non-toxic materials to the greatest extent practical.

I want to go a step beyond this and build a house that as closely approaches a passive level of energy use as possible – a “passive house“.  This means among other things that sufficient heat is captured and retained from normal daily activities (body heat, plus cooking, electronics, etc.) that active heating is never required, even during the coldest part of the year.  I will talk in detail about the choices that support this and why I think it matters.

Grid Flexibility

Related to, but separate from the passive house considerations is the idea of a house that can operate flexibly either on or off the grid.  Every existing home in our community has at least some “grid” requirement, either in the form of electric (grid-tied solar) or natural gas, or both.  Furthermore, the existing homes all rely on a community water supply that comes from a local aquifer before treatment.

With this house, I will be building in grid flexibility.  Essentially all day-to-day activities will be possible using only the solar panels provided on the house.  While some activities (such as drawing a 50 gallon bath of pure hot water) may be limited when off grid, in most cases normal practical activities (such as a 10 minute shower) will be possible.  I’ll talk about what activities are supported and curtailed, and how the passive house choices play into this.

Progress

This week, I’m scheduled to have the surveyors out.  Although they charge quite a bit to “mobilize” (mainly for travelling here and getting all their equipment set up, I think), I’m coordinating this effort with several other interested parties so that we can get more measurements (a total of about 20 survey stakes) for an estimated $850.  This doesn’t actually have a line item, so I have to decide whether to count it as “site prep” or just take it out of the contingency budget.  It seems logical that putting the stakes in at the corners of the site and the house is a form of site prep, so we’ll go with that.

Separately, I’ve received price quotes on excavation and foundation.  The first excavation quote came in at $21,000 which puts it 162% over budget!  Part of this is the lack of a budget for utilities (my fault) but they attributed part of it to a junior employee making the estimate and not recognizing potential places to economize (such as, putting both water lines and basement drains into a shared trench).  I’m working with them to get a more definitive estimate, but I’m also looking to get a second quote – if I want to keep things on budget, I need to not just go with the first price I get, even if the contractor in question has been very affordable in the past.

My first foundation quote was based on the use of insulated concrete forms (ICFs).  However, as I was considering things, I realized that given that the basement is going to be purely mechanicals, there isn’t any good reason to insulate it.  So I also requested a quote based on formed and poured walls – slightly thicker (8″) walls to compensate for the lack of other structural elements.  (It turns out this saves money in another area, because the ICFs are required by code to be covered with a fire-resistant surface – drywall – even though it’s not living space.)  The quotes broke out the slab from the footers and walls, so the total is $14,200 for footers+ICFs or $10,300 for footers+formed and poured walls, another $3,000 for the slab, and then on the order of $700 for waterproofing.  Add in another $1,000 if a pump truck is needed for any of the three operations.  (I should be able to avoid this by making sure that a regular truck can back directly up to the site.)

I am strongly leaning toward the formed and poured solution for pure cost reasons; this would give a total of about $14,000 which is still 35% over my budget.  Part of this can be explained by the addition of a “bump out” to install basement stairs.  Although I could use pre-fabricated concrete stairs (quoted at $1,800 delivered and installed) I could not use the prefab solution and still have the stairs be the width I wanted (48″, to handle large water storage tanks) or come out the distance that I need (72″) to keep the house within the appropriate envelope of the lot.  So some of that cost overage is compensated by the fact that I’ll be putting in wooden stairs instead.  (None of the comparable designs I used for budgeting had exterior basement-access stairs, so this was an oversight.)

A New Start

This blog has languished for some time while a number of shifts have happened in my life.  While I’ve learned many things in this time, I haven’t been producing much intellectual output aside from my work.  I wanted to change that, and as this timing coincides with receiving a building permit for a new home that I’m about to build, it seemed a great chance to combine the two threads.

So, while this post is a new start for the blog, it also represents a new start in the sense that economists would call “building starts” – a permit has been issued for #3 White Hawk Ln. (affectionately known as the Little Rental House), and I’m hoping to begin construction soon.  I expect to be blogging about the design, the process, and various other aspects.

The new house will be essentially one story, with two bedrooms and one full bath.  There is some additional loft space above that can be used for storage, office, etc., but other than the house is intended to be ADA accessible by design.  Beyond that, it will also have the highest insulation levels of any home yet built at White Hawk, in an attempt to reach “passive house” levels of efficiency.  (I won’t write that out in German because I think it’s a trademark if I do.)  I have a wide range of other “neat features” planned but I won’t spoil all the fun by writing about them in this first post.  I plan to be doing a lot of the construction myself to keep costs in check.

Obviously, I don’t have any interesting pictures to share, but I’m including a rendering of the house as seen from the west (looking in the windows into the kitchen, at the left, and the living room, at the right).  I have also uploaded the full plan set (large, 2.3M PDF) for people who might be interested in those details.

The current status is thus: I have the building permit in hand.  I am waiting for the surveyors to come out and mark for both the lot position and the house position.  I’ve started seeking quotes from contractors for excavation and foundation work, which I don’t feel qualified to do myself.  I’ve been learning about the differences between pre-fabricated Bilco basement entry steps and building the staircase myself; and I’m looking into how this impacts the choice of equipment that I can potentially put into service in the basement.

And I’ve already (based on the first quote) gone something like $13,000 over budget.  So… I’ve got to work on getting that down.  My estimate was based on the fact that the total cost for site prep and excavation for my current home was $5,300 (in 2007).  I expected this to go up, and resources like this suggest that maybe 50% increase was reasonable, so my budget was $8,000.   You can imagine my surprise when I got a quote for $21,000.  Of course, the quote isn’t quite comparable, because it includes work that on my current home was recorded under “utilities,” and which I hadn’t properly estimated in my initial budget.

I’ll keep you posted on how things look as I move along.

The Good, the Bad, and the Ugly: May 3

My neighbor Steve and I had a very fine weekend at Northland Sheep Dairy learning about horses and mules as draft animals from Donn Hewes’ Teamster School.  Some day, we think it would be amazing to have our own draft animals here on site… but for now, we still have a lot to learn. I was extremely excited about the possibility of learning to rebuild and repair old horse-drawn implements such as old McCormick Deering sickle bar mowers.

I’ll try to keep my notes on this weeks purchases concise. Good: Local cheese; used books; local port and brandy; car alignment check at a local service station.  (Although this could get better if my friend John becomes a neighbor and is able and willing to apply his mechanic skills to cars on-site.) Bad: Some garden implements from Agway, needed because old ones broke (plastic sucks).  Gas for car. Ugly: Greek mavrodaphne wine – this was something I tried years ago and wanted to sample again.  However, I will soon be bottling some homemade wine from my own Concord grapevines – which (you’ll have to trust me on this) is much better than you’d think based on Concord’s reputation. Also, wings and drinks at The Haunt’s karaoke night (again). Ambiguous: Going out to eat to meet with people.  These were three local, non-chain establishments: Viva Cantina, Hawi Ethiopian Restaurant, and the Rogues’ Harbor Inn.  In all cases, I’m sure many of the ingredients were non-local; Rogues’ Harbor probably did the best as my sandwich included local (free range, hormone free, antibiotic free) chicken, locally baked bread, local cheese, and beer from on-site, and all 5 beers in the sampler were also made on site.  Balance that against the fact that it’s the furthest of the three from my home.

It seems that now might be a good time to look in on some of the other purchases that have happened this month “in the background” – things like automatic payments for services or such things that don’t show up as receipts in my wallet.

Good: Trees from Musser Forests – they are relatively close, and once planted one hopes that the trees become a local and self-sustaining resource.  CO2 offsets from the Finger Lakes Climate Fund.  A donation to one of my Alma Maters – no goods received, the donation will do work locally where it is received. Service contract costs for my domestic hot water system.

Bad: Water filter service contract from Aquasana – this seemed like an economical way to get filtered water, but it seems unfortunate to be shipping filters across the country.  However, I only need a new one every 6mo or so, which is better than when I was using a Britta filter. Phone bills – no obvious alternative to a big national corporation for a true (works when the power goes out) land-line phone.

Ugly: Netflix subscription – this is split between me and a friend; neither of us have (or really want) cable, and both of us have relatively esoteric movie tastes (things like old episodes of Doctor Who, obscure political documentaries, and Bollywood comedies).  And, because much of what I’m actually interested in isn’t available “on demand,” I actually continue to have them ship me DVDs.  There are certainly other, more local forms of entertainment, but considering the relatively light weight of DVDs in the mail, I suspect this isn’t an environmental catastrophe either.  Electric bills – would be nice to buy a Solarcity Powerwall, but not in the cards right now, and otherwise relying on our lovely NYSEG for power.  However, by buying wind credits I can home that some of my power is coming from Black Oak Wind Farm.

The Good, the Bad, and the Ugly: Apr 26

Around the neighborhood, this has been the weekend of visitors, chickens, and trees.  A new family considering moving in to our village came to visit us from the west coast, and we had a pleasant flurry of get-togethers1 so they could meet many of us in person.  Meanwhile, our coop co-op was gifted with 13 chickens that a neighbor’s relative was giving away, and at the same time a different neighbor got a mini-coop (not a mini-cooper) with 3 chickens. On top of that, a third neighbor got his first nursery shipment of the year (a miniature Valencia Orange) and I began digging planting holes for this year’s coppice trees (swamp white oaks and river birch from Musser Forests).

Good: Milk.  Beer: At The Haunt’s Karaoke Night – Ommegang Rare Vos, and possibly Bass, although who can tell where the heck this is made now that it’s owned by a multinational.  (I mean, Bass is possibly good.  Bass was definitely consumed.  I might have embarrassed myself on stage, but not because I had too much beer to remember the evening.) Lunch: At Viva Cantina – they source many things locally, although I cannot say with any certainty where all the ingredients in my lunch came from.

Bad: Car Tires. Actually, I was having some trouble deciding which category to put this in, and “Bad” seemed lonely. There’s no question that my car dependence itself is in the “bad” category. But as tires go, I was extremely pleased with the fact that Yokohama Tires has a “Sustainability” link at the top of their web site, and seems to be doing real measurable things in terms of GHG emissions and reduction of landfill-bound materials.  I also made the phone calls needed to determine that the actual tires I was buying were made in Salem, VA. Electronic Parts. I bought a power supply for the new LED path lighting I installed from DigiKey. I couldn’t come up with any good way to get something highly efficient to run these highly efficient lights2, other than buying it new by mail order. Technically, I could have built it myself, but I would still be ordering the parts from who knows where… and this is at least UL listed! Still, if TSHTF in the next 5 years (typical LED lifespan: 50000 hours) it’s nice to know I could.  But I’d probably have more to worry about than path lighting at that point.

Ugly: Breakfast. I needed something in walking distance of the tire store that was open at 8am, and although there are local options 15-20 minutes away, Panera was 3 minutes away, so convenience got the better of me. I guess they do employ people locally to bake for them, but it’s not like Dolce Delight. Dinner. Wings at The Haunt are probably not sourced from anyplace I would be proud of.

  1. A side note here: I made Maza (barley cakes) again, only this time I was able to use on-site sourced honey and regionally-produced sunflower oil.  However, I added non-local raisins to make them a bit fancier. ↩
  2. My LED lighting is consuming 1.75W total including the power supply. A quick bit of research concluded that it was cheaper – not counting LED lifespans – to run them full time than to put them on a mechanical timer, because most of the mechanical timers consume 2-3W by themselves.  Isn’t that crazy? ↩

The Good, the Bad, and the Ugly: Apr 19

My parents were visiting this week, helping out with their home that is being built in our village, and helping me out a lot along the way. (Thanks Mom & Dad for all the garden and building support!)  Their presence changed my shopping patterns in some interesting ways. For one thing, my mom decided that she needed to bring all the food for the week, somehow believing I had been existing purely on air and sunlight. (OK, who are we kidding, until this week it would have been air and snow.) She was shocked (“shocked, I tell you”) when she found she couldn’t fit it all in my fridge. Conversely, their presence got me started on some home-improvement projects I had been putting off, with attendant purchases.

Good:  I go to a local dentist.  We don’t have one on site (yet) but I think that’s good enough.  (Also good – just going for the cleaning and not having any cavities or other problems to complain of.)  On the grocery side I picked up some milk (inspired by the butter last week, I got this from Byrne Dairy, which has returnable/reusable glass bottles!).
Plantings.  I picked up planting potatoes and onions at our local Agway. Admittedly I’m not certain where they get these, but considering these will be truly growing In My Back Yard it’s hard to call this one bad.
Concrete blocks.  I picked up a few of these for a construction project, thinking that they were definitely going in the bad or ugly category.  It turns out that at least some cement is made regionally and it may be boat-shippable. Not sure where mine came from, but in the realm of how to get things here, this is at least plausible. (Not that extractive industries themselves are sustainable. Also, I feel guilty buying this from a big box store, but I was trying to match what was already installed.)
Bar drinks.  My “bars and restaurants” post was a result of Wednesday and Thursday night’s activities.  I try to get to karaoke with DJ Dale at The Haunt when I can, but this week we were stymied by a confusing calendar which showed both the karaoke (false) and a band playing (true).  We wound up at Felicia’s Atomic Lounge instead, a place that has a distinctly hip NYC feel but with a heavily locally-slanted bar menu.  I selected a cocktail featuring one of the two local gins, and got some things for the other folks (including the folks… my parents) that probably erred on the local side though I don’t have all the details.  On Thursday, I explored the opposite side of the STBC/GLBC equation from last week, and had a Right*O*Way*IPA at our local “Thirsty Thursday” networking event.

Bad: Bananas.  Source of potassium for parental units.  Not local, not likely to ever be.  At least they were organic, and maybe they can be shipped by boat, which may be more sustainable.  Rice.  Still a staple grain in my diet.  This is Lundberg organic basmati from California; although this is domestic, it’s possible that the shipping across the US is worse for the environment than shipping by boat from India.  That’s a hard one to calculate.
Propane Refill.  After 18 months (548 days, if you want to get precise) I used up my first 40lb propane tank.  That’s 0.07lbs/day or if you convert to CO2 emissions, about 3oz per day.  (Although there’s a big difference between living and fossil carbon, considering I breathe out 2.3lb of CO2 each day, I think I’m not going to get too bent out of shape about 3oz to cook my food.)
Misc fasteners.  That’s what they call all those little nuts and bolts at your local (or national chain) hardware store. Regardless of where you shop, there’s a pretty good chance they get their inventory from the Hillman Group.  It could be worse: nearly 60% of what they sell is made in the U.S.  But… it’s a bit disturbing how dependent we can become on a single bottleneck like this one distributor.

Ugly: Toothpaste.  I can (and do) buy Tom’s of Maine, but it’s not at all clear to me that they’re “of Maine” or even “Tom’s” any more, since they’re owned by Colgate-Palmolive.  Interestingly, their web site doesn’t whisper a word of this vicious, nasty rumor… er, fact.  Still, I’d like to keep not having cavities when I show up at the dentist, so what to do?  Brush and floss as best as I can.
Cat Food.  I’m not entirely sure what to do about this.  If the furball would feed himself entirely off of the rodents In My Back Yard I’d be rather happy, but he seems quite certain that I own him 3 (or 4, or 5) square meals a day, and will take it out on me (or out of me, in flesh) if I don’t live up to his expectations.  And… whaddya know, he’s allergic to grain.  So unless I want to deal with cat dietary allergies (don’t make me elaborate) I wind up feeding him the fancy all-fish stuff made on the west coast.  Well, at least they sell it in local stores?
PVC plumbing parts.  There really should be a better alternative, but when people don’t remember that you have to leave faucets open in the winter so they don’t freeze, I don’t want to pay for replacing the parts with brass.  I still have to go to Agway and get a replacement for the 55-gallon drum (recycled, food grade, less than $20 last I checked) that burst open from the freezing water – and figure out if that fits in a Prius!

Also, two more reasons that I love our local Agway.  First, when my second propane tank appeared to be malfunctioning, they help test it, bleed air from it, and topped it off again for free.  Second, when the sprinkler head for one of my garden watering cans cracked, knowing that these aren’t sold as replacement parts, store manager Dan Lee found a spare one he had kept from a shipment that had a damaged can, and gave it to me for free.  In this day and age, who does that? Ithaca Agway does.

The Good, the Bad, and the Ugly: Apr 12

Having just returned from a trip, and expecting friends and family staying with me, I had some grocery shopping to do this week.  For this good/bad/ugly post I’ll focus on what I’ve bought since I returned to town, since I already posted about the travel.  I also want to try to condense this a bit since I know my posts tend to ramble.

Good: local bread, local hot dogs, local and regional cheese, regional butter, local mushrooms, local potatoes and rainbow carrots1, locally baked cookies.

Bad: Kalamata olives (unknown origin).  Lemon juice (Florida).  Coconut milk (unk.)2  Ginger (unk.)  – I’m not clear on whether this could grow locally.

Ugly: Domestic parmesan 3.  Tortilla chips 4.  Frozen peas5. Organic chicken thighs6.  Raisins (CA)7.  Organic onions and sweet potatoes (unk.)8.

There’s one other “bad” that deserves special mention: gasoline for the car.  Is there such a thing as a “local” gas station?  Somewhat surprisingly, the answer is a qualified yes: Mirabito.  Although they don’t refine their own fuel (their web site shows “materials safety data sheets” or MSDS from Citgo, Valero, and Sunoco) at least much of the profit is being recirculated regionally.  They’re also a strong promoter of alternative fuels (E85 and biodiesel, for example), and even I think those are a dubious sort of “alternative,” at least it shows some awareness that there is an issue.  My guilty (“ugly”) plea: that’s not where I normally buy gas!  I have been favoring Hess for years since I found out that they were a progressive company that was not doing things like fighting fuel economy standards for cars. Unfortunately, they’ve made a big move into fracking in the last couple of years and I should probably shift my business. So perhaps this is a good example of this blog getting me to re-evaluate my actions.

  1. Sorry, not sure which farm. ↩
  2. If someone can figure out how to grow olives, lemons, or coconuts in NY, they’re either a miracle worker or a global-warming survivor.  I should talk about this more at some point. ↩
  3. Probably from Wisconsin.  This gets into the big hairy question of why we can’t make our own cheese on site – the illegal status of unpasteurized milk – which should be a blog post in its own right. ↩
  4. We grow enough corn locally that it seems ridiculous to buy national-brand chips, but I’m not aware of any local alternatives.  I guess you need economies of scale to sell a pound of chips for $4. ↩
  5. Called “Woodstock,” but distributed from RI and declared “product of USA.”  I guess that’s better than world peas.  We grew a lot of beans last year but not much in the way of peas. ↩
  6. Bought for my friends.  We have good local chicken farmers but they mostly sell whole chickens which makes it harder to grab one for a quick home-cooked meal.  For myself I mostly eat vegetarian. ↩
  7. It seems like we ought to be able to find local raisins.  Our attempts to make our own were frustrating, because it takes an unbelievable amount of dehydrator time to get raisins from fresh grapes. ↩
  8. Would normally grow these, but ran out of stock. ↩