Image Credit: Energy Vanguard
Image Credit: Energy Vanguard This rendering shows a home that's a good representation of a Pretty Good House. It's under construction in Atlanta, Georgia now and should be finished in summer 2012.
Image Credit: Energy Vanguard The designer of this home neglected to consider the water coming off of the roof right above that window. A Pretty Good House will rely more on design for water management so that the flashing details aren't quite so important as they would be here.
Image Credit: Energy Vanguard
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Let’s get back to the Pretty Good House concept now. Last month I wrote part 1, called Is the Pretty Good House the Next Big Thing?
There I discussed mainly the design, building envelope, and heating and cooling systems. Here I’ll take it further and look at water (management, conservation, and heating), performance, verification of the builder’s work, commissioning, and homeowner education.
The essential elements — Part 2
To continue with our discussion of the essentials, let’s take a look at some of the other main areas of building a Pretty Good House.
Water
The Pretty Good House needs to get the details right for three aspects of water.
Management. This is a given right? Getting the flashing details correct, installing an effective drainage plane, and keeping water away from the foundation is something that should happen on every house. Some problems are best avoided with good design (like not putting a window where water pours off of a roof, as shown in the photo below). Some need careful attention during construction (like installing the kickout flashing above that window that IS installed under a roof).
Conservation. We use a lot of water in the U.S. According to Data360, we’re #1 in the world in per capita water consumption. Since 1992, we’ve done a lot better at putting in water-conserving fixtures in homes, but there’s still room for improvement. The two biggest opportunities I see for most homes are hot water distribution and landscaping. For the former, we need better design and perhaps demand-type recirculating systems. Rainwater catchment and using drought-tolerant plants and less lawn are the way to go to reduce landscaping water.
Heating. The choice of a water heater is a complex issue. Sometimes a standard water heater is fine. Sometimes an expensive but more efficient heat-pump water heater makes sense, especially when powered by photovoltaics. In fact, that combination could be better than a solar thermal water heater. Whatever water heater you choose, just make sure it’s safe and the fuel makes sense in your area.
There’s plenty of opportunity even without discussing how we heat the water, however. We waste a lot of the energy of heated water by stranding it in uninsulated pipes in distribution systems that are too big and spread out in many homes. The solutions:
- Design to have a centrally-located water heater or smaller distribution system.
- Insulate all hot water pipes.
- Use a water heater with heat traps (to prevent thermosyphoning).
- Install a demand-type recirculating pump (not continuous).
Performance
A Pretty Good House should be a high-performance home, keeping the occupants comfortable and healthy, their energy bills low, and the house intact. When the building envelope and mechanical systems are done right, when the design minimizes future problems, and when understand how to operate it, a Pretty Good House is a pretty good place to live.
Do we need to quantify the performance and set thresholds? I think so. Looking at the HERS Index is a good place to start when modeling the house, but I like energy intensity as well. To throw out an arbitrary number — Hey, that’s what everyone does! — let’s say a Pretty Good House should have a HERS Index of 70 or lower. I’ve looked at a lot of rating files from different builders, and I think this won’t stretch them past their elastic limit, especially given where the energy codes are taking us. (See Martin Holladay’s overview of the 2012 IECC.)
Using energy intensity, I’d say we should aim for 5 kilowatt-hours per square foot of conditioned floor area or lower. For those of you in cold climates with lots of heating degree days, you can normalize to that factor as well, but I don’t have a good feel for what the numbers should be there.
In addition to setting targets, though, I think we need to have some followup to see how well the house actually performs. Does the house actually perform over the first year as well as the model predicted? Were the occupants comfortable? See below for more.
Verification
A Pretty Good House can’t be pretty good just because the builder says it is. It might turn out to be pretty good, but one of the best things about the Energy Star new homes program is that it requires third-party verification. A home energy rater gets the plans and specs in advance and completes the projected rating. Then they go out and do the pre-drywall inspection. At the end, they do the final inspection and update the HERS rating file.
That’s a pretty good way to ensure that the house gets built right.
Commissioning and followup
One thing that doesn’t happen much with residential construction is commissioning and followup. Once the house is complete but before it’s occupied, it should go through a complete commissioning process. This is common for commercial buildings, and is a pretty good idea for residential, too. I wrote a little about commissioning a new home last year but would like to see a more robust procedure. The idea here is to check out all the systems and make sure they’re performing as they should be.
Followup should be part of the process, too. When the home is a year old, let’s get out the energy bills and interview the occupants. Let’s look at the envelope and the HVAC systems. What’s working well? What’s not working as it should?
Homeowner education
Finally, occupant behavior turns out to be a pretty big factor. Sometimes things don’t work well simply because the occupants don’t know how to operate the house properly. A good, detailed homeowner’s manual can help solve some of the problems, but how about an orientation session, too? Give the new owners some hands-on training in how to live in their new home.
And how about the idea that Sam Rashkin promotes — the 60 year home warranty, as offered by Toyota Homes in Japan? Read more about this and his other ideas in his book, Retooling the US Housing Industry.
What’s next?
This has been a great exercise in thinking about how we can improve homes. Those of us who work in the field need to keep rethinking how we do things and striving for continual improvement. The energy efficiency and green building programs have taken us a long way, but the reason we’re having this discussion now is that there’s a lot of frustration with where many of them are headed now.
So, let’s keep asking questions. Here are a few more for you:
- Should a Pretty Good House be green?
- Should it be affordable?
- Should it be solar-ready?
I look forward to your comments.
Allison Bailes of Decatur, Georgia, is a RESNET-accredited energy consultant, trainer, and the author of the Energy Vanguard blog.
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13 Comments
A PGH should be versatile and attainable as well as sustainable
I would say that affordability and versatility ought to come before solar-ready or "green" whatever that even means anymore. If the average person, builder, or designer can't produce the home on a variety of lots, i.e., irregardless of passive solar siting, there's no point in prepping it for solar. Solar is getting much cheaper anyway and just as people do today, they will find ways to incorporate it whether their house is prepped or not. Affordability and therefore attainability is paramount. Most people cannot spend lots of money whether its up front or throughout the life of the home. The home should also be designed to last more than 20 years. The PGH should be something the average person can understand, afford, and appreciate with minimal or reasonable trade offs, e.g., no basement, smaller scale, simpler form, etc.
Pretty Good House is pretty good
Allison, you just posted an interesting list though some of it seems to point to added costs. I know you mean well, but to me low cost incentives verses high cost disincentives is a go green simple workable plan. Some of your listed ideas high costs might equal high use of the planet of nature not protection of the planet.
Some added ideas;
Increase the cost of municipal centralized water and fossil energy
Eliminate monthly minimum utility charges thus encouraging reduced consumption to zero monthly whenever possible.
Publish free home designs that use net zero water and energy.
Open source design software for PGH
Small homes
Less homes
Less people
Less or no net energy use
Less municipal sewer and water not more
Etc
I look forward to the discussion though
PGH discussion
Great article. It's good to see the PGH topic getting such recognition. It started up here in Maine where the Passive House benchmarks sometimes don't make sense with certain deminishing returns. I believe the idea was spawned that homes could be brought to say R-30 - R40 in walls and be pretty good, but not certifiable. Most people that want a comfortable and efficient house with lower heating costs don't necissarily care about certifiying their house to either Passive House or LEED programs. I think that the general consensus has been that PGH is near all these things, but stopping with things that make sense and not throwing caution to the wind to "getting certified." I'm not sure about a HERS rating benchmark for PGH, but in my opinion it's a whole lot closer to the HERS 10 - 20 range and not the HERS 60 - 70. One idea I like about the PGH at this point is that there aren't strick guidlines and no PGH software. I also like the idea of a PGH being nearly Net Zero. Not necissary Net Zero, but pretty close. That's the kind of PGH I'd like to live in.
Look forward to seeing you up here at Maine Green Building.
costs
All the contractors love tossing around "getting commissioning inspections, getting HERs ratings, getting blower door tests", but I being a homeowner have seen this while building my VERY good house, that these all cost money. Perhaps trying harder to make it affordable for a home owner would be a good idea. How about most publishing of techniques to attain these goals - pictures, descriptions, code compliance methods.... I asked the Passive haus people how much for passive haus consultants to certify my house, and it was 18000 $. Sorry - If I can maintain the concepts, the I do not need to spend the 18k$ for certification. Sorry , I do not see the $$ in certification if there is no compensation...And as for confirmation of the build, I am building it, so I can say how I built it..
Thanks for the great comments!
Brian, aj, Jason, and Mark: Thanks for the great comments. It's clear that what one person considers a pretty good house may not be good enough for another or too expensive for a third. I agree that affordability is important because if someone has a lot of money, they shouldn't settle for just a Pretty Good House. They should build a great house. But it all depends on what your reference point is. Are you comparing the PGH to a code-built house or a Passive House?
Mark, since your remarks referred to making it affordable for the homeowners, don't forget to factor in the operating costs. I'm not saying that $18k in certification fees will be cost-effective, but spending extra in the up-front costs can certainly be affordable for the homeowner because they pay the extra cost a little bit each month, not all at once.
Also, you said, "And as for confirmation of the build, I am building it, so I can say how I built it." If you're reading and commenting here at GBA, you're probably one of the rare builders who can do that, and if your buyers know and trust your work, that's probably fine. The value of third-party verification, program certification, and HERS ratings, though, is that they give homeowners a way to gauge how well a builder did when they don't know and trust them.
A PGH might also be one that already exists. The sheer fact that
so much discussion revolves around new construction is unfortunate and frustrating. Finding ways for homeowners to affordably transform an existing house into a PGH is where the real skill comes into play. Homeowners need to be able to spend money that they recoup relatively quickly if not immediately in the form of reduced energy costs and increased property values. This idea that one should have to pay up front in order to achieve long term efficiency and sustainability, while logical, just isn't going to fly for much longer. The reference points need to be realistic. A PGH is the one you can afford now and if you haven't recouped whatever premium you pay for improvements within the first 5, there's very little incentive to pay the premium in the first place. So, A PGH is one that gets to the root of the issue which for most sits in their wallet with a tertiary benefit of reduced environmental impact. Often doing things better simply requires forethought and experience rather than any actual added expense. Doing things better or differently doesn't necessarily mean, and often doesn't mean, spending more money. Its about selecting the right course of action up front, not paying a premium. Idealistic perhaps but also brutally honest.
Sprawling?
Are transportation cost factored into the Pretty Good House? Obviously if one builds
out on the edge of sprawl. completely auto dependent, the energy use over time
will be enormous.
question re: PV and hpdhw use
Allison, you mention the use of a heat pump water heater with PV panels for use in a warmer CZ like this one. The idea is appealing but I wonder if it makes as much sense for a family of two. Wouldn't the low use (especially during the peak solar hours) cut down on the value of the PV installation? Or is your notion that a sufficiently oversized tank would compensate and provide some "pretty good" hot water?
Thanks for following up on the PGH with another nod to those of us in the South. I'm convinced the PGH approach is more suitable for someone like me (when I build or reno next year) than going the way of something like LEED. Not at all interested in PassiveHouse, not at least until they can figure out what they mean by their own definitions.
Response to brian m
Yes, absolutely existing homes can be pretty good, too, and there's a lot of work going on there. Since we all finance most of the big stuff we buy, including energy retrofits, the metric to look at is cash flow, not payback. When you say "if you haven't recouped whatever premium you pay for improvements within the first 5," you seem to be looking at payback, which is irrelevant when financing. If I'm paying $50 extra on my mortgage and saving $50 on my energy bills, the 'payback' is immediate. With an Energy Efficient Mortgage, you can do that.
Response to bryan shephard
I've been spreading the word about peak oil since the late '90s, and you're absolutely right about transportation costs. The "drive-till-you-qualify" housing market is coming to an end now with fuel prices that are going to continue the upward trend we've seen for the past 7 years. If you want to feel terrible about this, just go read Jim Kunstler's book, The Long Emergency, or watch the film, The End of Suburbia.
HPWH & Southern PGH - response to JoeW
Yes, if your water usage is low, then expensive water heating options of any type may not make sense. The two links I gave in that section take you to two recent articles by Martin Holladay, which cover the technology pretty well. In an earlier article of his, All About Water Heaters, he wrote about point of use water heaters that can make sense for low use homes.
Glad you like the PGA approach and my take it on it for warmer climes. This isn't a program with any rules, though. It's just a bunch of people talking about building homes in a way that makes the most sense. Some people do still want the ENERGY STAR, LEED, or Passive House certification or for the house to be Net Zero or Zero Peak in its energy performance, but a significant number of people seem to be looking for something else, too, and I believe the PGH concept is a good exercise.
Energy costs are still low on the totem pole
Allison, Jim Kunstler must not live in the suburbs. If he did he would know that the expense front and center that is getting too high for suburbanites is property tax. For example, all my NJ suburb friends are starting to retire. None of them ever watch the price of gasoline or their electric bill. I am in their homes and when they wake up, all the lights go on till they go to bed. They drive by stations I stop at for gas that are ten cents a gallon less so they can go to the name brand station that they think has the look and the safer workers and on and on (lifestyle thing, impressing others thing).
But property taxes starting to close in on $20-30,000 annually have their attention! High Property taxes are going to shift many a baby boomer to anywhere that they can half their current bill. I know this because it is the latest topic of interest with many if not all my retiring mates.
Get ahold of Kunstler and have him look into my post. Energy costs are low on the totem pole for what we used to call the upper middle class. Oh and even one notch higher if not the highest for this group is two to three several hundred thousand dollar kids college expenses.
Every $10-30,000 check one writes makes the $200-800 energy bills vanish from the conscience.
Pretty Good House
Once upon a time there was a carpenter in Maine........
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