Image Credit: Latin American Technical Education Foundation
More Musings of an Energy Nerd
Green building websites can be confusing. One site might tell you that a green home should include spray foam insulation, a tankless water heater, and a geothermal heating system. After you’ve absorbed this advice, you visit another website, where you learn that spray foam is a dangerous petrochemical, tankless water heaters are overpriced gadgets, and “geothermal” systems aren’t really geothermal.
Eventually someone tells you that you can usually trust advice from Green Building Advisor. After reading a few GBA articles, you start to feel more comfortable. But it only takes a few clicks to end up deep in a thicket, even here at GBA. In no time at all, you are stumbling again.
One GBA article explains that a good way to ventilate your house is with a central-fan-integrated supply ventilation system. Hunh?
Another article advises you to aim for 1.5 ach50. What’s that?
Still another article talks about a type of insulation that is air-impermeable but vapor-permeable. At this point, you’re probably tempted to go back to the website that told you to buy a tankless water heater. At least that advice was easy to understand.
Don’t give up just yet
But still, you keep on studying. This type of reading is painful, like learning ancient Greek, but you know that there’s a prize at the end of the tunnel: someday, you’ll finally understand Homer’s wine-dark sea — or at least be able to talk to your builder intelligently.
So you practice pronouncing “polyisocyanurate,” and then you go to your local lumberyard and order some from the guy behind the counter. He answers, “Poly what? Never heard of it.” (This actually happened to me a few years ago.) At that point, you don’t trust any information found on the web, and you’re probably…
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31 Comments
Excellent
I think someone finally spelled out the PrettyGoodHouse.
Nice Job
Concise overview of where to start. I always like to say that green building is all about the process - materials are secondary.
You did a great job of avoiding your cold climate bias with one minor exception - your suggestion to minimize windows on the north side of the house. In hot climates, I believe that north windows are a good thing - natural light and minimal heat gain.
Response to Carl Seville
Carl,
Thanks for the feedback. I have edited my advice on north-facing windows in light of your comments. I always appreciate hearing from Southern experts like you.
City of Vancouver Design Guide
The city of Vancouver has published a passive design guide that is good starting point for beginners. It has information in there that I have not seen elsewhere. While the guide is geared to Vancouver, most of the design principles apply to all.
http://vancouver.ca/files/cov/passive-home-design.pdf
Great tips
Thank you, Martin. As someone who is in the process of bidding a new "green" home, I really appreciate this distilled version of what to do on this type of project to minimize the misadventures.
What i like the most of this
What i like the most of this article is your "entre en matiere " .... hahaha
u have a way to setup the article ... hahaha
nice one again :)
and i do enjoy your "north" bias !!!
Siting and beyond the build
Another really good article Martin. My biggest objection is that it just covers one phase of a multi-phase project. I'd like to see more discussion of the importance of picking a good site, both for solar and environmental issues, but also for longevity of the project, which might mean a trip to the municipality planner's office to see what the long term development plans are for that area.
I'd also like to see discussion of what comes next. After you find your builder who is wonderful at designing a tight, well insulated, low energy using house, how do you pick materials for various components and elements? There are standards for everything, sure, in many cases multiple standards. Sometimes they overlap, sometimes they conflict. Some manufacturers don't meet standards, or only meet some of them, and yet others don't participate even though they probably exceed standards (point in case, I was just looking at the kcma.org website, and poggenpohl cabinets are not listed as being rated, some of the more expensive cabinets on the market. Doors are an example of multiple standards, many doors are rated for either insulation value, hurricane rating or security abilities, but not many seem to be rated in all). Figuring out which standards are important for each component of a home is simply overwhelming, let alone resolving conflcts and all the other issues.
Finally, some tips for post-build maintenance. How do you make sure that you keep your house running at a low energy use level.
Response to Paul W
Paul,
You're right -- this 1,800-word article doesn't cover every aspect of residential construction.
Your suggested topics -- choosing a good building site, material selection, and maintaining a home to assure energy efficiency -- are all good ideas for upcoming articles.
In the meantime, at least two of the topics -- choosing a good building site and material selection -- are covered in the GBA Encyclopedia.
Here are a few articles on site selection:
Siting with the Sun
Location Efficiency Trumps Home Energy Efficiency
Location Efficiency
Reduce the Need for Driving
The GBA Encyclopedia has information on materials selection in a great many articles, including the articles on foundations, walls, windows, roofing, siding, insulation, and plumbing.
Great elevator speech
Thanks Martin for this one pager. I'll be pointing many newbie to this page so they understand the concept behind how to plan a better house...
Thanks for the good advice.
Climate change is now. This site's noble effort could be a big step back from the brink if we have enough participation.
Insulation and air sealing is clearly a major key to the success, but,
With all this talk of spray foam insulation inside the walls of homes, exposing homeowners to the off gases we really need some discussion of Toxicology of these exposures over time in very tight homes. Isocyanates for instance are a known as a 'bad actor in human exposure' in the field and should not be taken lightly, just to name one. When I see walls and ceilings sprayed full and covered in drywall, and it called 'Green', I get very worried for the occupants. EPA is taking a second look now as they should.
The initial reports on some of the compounds are very troubling and need to be discussed, and more research done before we have such widespread use. This will be very difficult if not impossible to mitigate not to mention the long term exposure health effects in 'super tight' houses.
Thanks for a Great Site.
YKIEM. SOLAR GEOTHERMAL INSTANT HOT WATER
You keep it easy enough Martin
thank you again
interesting that there are so many different word phrases playing on the marketing of all the things
that you addressed
I would like to identify
that if we have a tax credit with geothermal using the term for Earth Heat geo thermal and deep ygeothermal only but for masses of folks retrofitting to New...its all geothermal
I have had a paradigm shift in discussing any projects like these with deregulated applications of energy
it's a better utility bill first
then a better building
Best air Distribution of heat with cooling and
100 percent heat recover to domestic making of instant or regular hot water
whenever possible in the air conditioning mode if air conditioning is used
n making 2700 square feet into 3700 was with only a half inch of spray on foam to improve the tightness and all the rest fiberglass bats even though I specified cellulose I can't argue with the zone 6 $130 a month budget on the all electric home...
Using a 5ton geothermal ground loop on a four ton total compressor system that has dual
one and a half plus two and a half times and then a third stage of all four tons
in domestic 100% instant and loop pumps off in recovery
HW heating in air conditioning mode
Could you repeat that?
In English this time?
I think it's like a Beatles record:
the meaning reveals itself when it's read backwards.
Cutting a way through the thicket photo above.
I find the title photograph amusing ...
Why doesn't the guy just walk around or through the wimpy little branches?
I know that I am often guilty of "overkill" thinking and design....
Maybe that's what attracted me to Passivhaus :-)
Response to John Brooks
John,
Extending the metaphor: sometimes, when one's progress is impeded by dense vocabulary and complicated technical concepts, it makes sense to slow down and study -- to understand one's surroundings thoroughly, until a way forward becomes clear.
For beginners, however, this approach can take a long time. So sometimes a machete is useful, because beginners don't always have the time necessary to understand where they are and find a path forward.
Excellent Article and Advice
Martin, the article and advice are excellent...
I only find the photograph amusing.
Another very informative article
Thank you for another very informative article Martin.
As a future high performance home owner I have learned much from all of the articles that I have read on the Green Building Advisor site and the Building Science Corporation site has been extremely helpful as well.
The only thing that confused me was the 'Adhered "manufactured stone" veneer over OSB wall sheathing" red flag. After more thought I came to the conclusion that "adhered" is the key word here in that adhering it directly to the wall was the problem. Based on what I have learned over at BSC, it should be fine if it is installed over a 3/8 inch drainage mat over a water resistive barrier.
Your attic comments kicked of another area of concern that I still need to learn about and that is attic access. I have to learn how to make sure that it is well sealed and insulated.
Sadly, I don't think there is anyway to make my house and lifestyle truly green. I want a small house but the wife wants a large one and her vote is larger than mine. Her horses basically defeat any attempt at a green lifestyle although there are a couple of benefits. The barn's roof will make an excellent spot for PV panels and the processed horse food will continue to allow me to grow a very lush vegetable garden.
Response to Tom Peterson
Tom,
The horses fit well into a green lifestyle -- especially if you get rid of your car.
A wall incorporating adhered manufactured stone over OSB contains so many pitfalls, it's hard to know where to start. First, there is the problem of taking concrete and using it to make small concrete pancakes that are supposed to look like stones from a distance. I mean, really.
Then there is the problem of OSB sheathing, which turns into oatmeal very quickly if it stays wet for a few months.
Then there is the problem that the OSB is very difficult to inspect once you have anything adhered to it. (At least with vinyl siding, you can unzip a few courses and take a look at the sheathing.)
Then there is the problem that very few installers know how to flash a wall, and the fact that most U.S. windows dribble water into the wall assembly from the lower two corners of the windows. Where is that water going?
So, if you swap the OSB for rigid foam -- and you include impeccable flashing -- and you include a drainage gap with openings at the bottom to release liquid water, and openings at the top to allow the escape of ventilation air -- and if you use real stones instead of concrete pancakes -- you might end up with a green wall assembly.
But really, Tom -- that's a lot of things that you have to make sure are done properly if you don't want the wall to fail.
Wow
Martin, thank you for the detailed response!
I must be delusional because I keep thinking that by now I should know a fair amount about building science based on all of the books and articles that I have read. Hopefully what I don't know doesn't do my house in. I'm confident that I will not find experienced tradesmen that have an appropriate understanding of building science nor of a house as a system building approach.
Based on your response, I will conclude that placing stone or brick on an OSB wall would not be conducive to a house with a long life either. A goal in the back of my mind is that I would like the owner in a century from now to reflect back at how well the house was built a century earlier.
Is it unreasonable to assume that the water risks would be negligible if the stone or brick work was at the north entry to the house which was covered by a (eight foot deep) porch? Our house will be built in western Wisconsin.
Response to Tom Peterson
Tom,
You are right: If you protect stone veneer with an 8-foot-deep porch, you don't have to worry about water entry issues (assuming, of course, that the roofer who roofs the porch knows how to flash the top of the porch roof, where the porch roof meets the wall -- a type of flashing that can be tricky if the wall includes a rainscreen gap).
However, you are stuck with an aesthetic problem: I can't imagine that you want a house that includes one type of siding over most of the house -- perhaps fiber-cement, to mimic clapboard -- and then another type of siding at the entry door -- perhaps stone veneer, to mimic an old stone house.
If you want your house to look like a stone house, it makes sense (aesthetically) for the entire house to look like a stone house. Otherwise, it's just a jumble, with glued-on siding.
The worst example of glued-on siding I ever saw was a house with two dormers; the dormer cheeks had fake stone veneer. The builder didn't even realize that a stone house can't have stone dormers. I mean, really -- where are the support walls for these fake dormer cheeks?
Great interview Questions!
Martin, Fantastic advice without all the jargon that kills newbies. I love your Builder/Architect/Designer questions. Can you expand on that for a future post? I'll be sure to tell my prospects to read this before interviewing me! Best, Matt Risinger Austin, TX
Response to Matt Risinger
Matt,
I'm glad that you liked my article.
Feel free to expand on my list of questions for builders and designers in one of your blogs if you like. Of course, it would be nice if you gave me some credit for starting the ball rolling... and maybe included a link.
Have you ever
Great article Martin.
Another question worth asking the builder is have you ever tracked the energy consumption of a building you have built? Do you know how many therms, gallons, or watts it takes to heat and cool your homes, and have you ever confirmed it after you built. So many new homes tested have have excessive fan and pump energy regardless of where the distribution is located.
It's hard for builders or their HVAC installers to get better if they don't understand what they are up to. The same could be asked of the energy engineers/ designers, have you ever checked how much energy one of your designs consume? in my region I have never seen a mechanical engineer check their design for actual energy consumption and as a result their is a big gap between what homes need and what's being specified. If it's possible for a builder to learn what an ACH50 is than it should be possible for a mechanical contractor to learn what static pressure is. At a minimum they will need to understand that to install a good ventilation system.
Response to Gavin Healy
Gavin,
Great questions -- great suggestions. Thanks.
English Solar GeoThermal Instant HotWater
Martin ! Thank you again.
Having a couple of questions though:
how small is a "smaller home" and
how much is recommended spent on "engineer" of equipment selection?
and how much for the blower door testing?
Since GeoThermal is really any Earth-Heat below grade transferred, and the ground loop of closed-loop a GeoThermal project IS directly related to having to know how to engineer an understanding of Heat Loads and Cooling heat gains to the loop (sizing), what is saved in upfront testing and engineering by simply demanding a loop-performance contract?
Such a contract that is in writing for such as in 50-degree ground, 'minimum 34 degree loop fluid incoming to GT Unit inlet in an 'average' cold winter, at 3gpm/compressor-ton (~ 2.7 per rated AHRI box ton- "size" ) i.e) like I guarantee in writing in zones5 to 6 about 6500 to 6800 degree day areas.
Lowest first cost GeoTermal with all relative components of including a water tank and On-Demand HotWater instant heating with a forced air unit (also integrating reasonable small radiant heating from one same unit) all if applicable tax credits are applied for now are not as "very" expensive as one would compare to systems requiring two units to do what others can do super-efficiently with one GeoThermal Unit as a System. - I have several reasons to believe (installing since 1980).
Another question is since V-Star compressors of IQ/Variable drives are only offerred in wide application ranges, as 2.1/2 and 4.1/2 and 6+ Compressor-Tons: How "engineering" wide are the margins of application(s) as to the old considerations of single speed equipment divided in half ton incremental selection 1/2 to 5 compressor-tons, relative to balance points being 10 degrees at one home and 5 degrees at another with LOAD-MATCHING equipment?
Monitoring seems simpler since 2007 since systems can have 7 to 9 sensor readouts and logging of all sorts of things for varifying loop and runtimes and more, so what about the history being able to really track simple low cost pre-building design builds vs. ?
$1000-3000 in additiopnal fees to date that could go towards reviewing and purchasing what already works so well yielding 5500 sq ft homes HVAC HW families of 6 and 7 @ 13,000 kwh (HVACHW metered) to 3200 sq ft 2 story over uninsulated basements using only 8,000 kwh for all HW and Heat and Cooling without ERV's etc. (?) -I do not mind harsh correctively strict comments or Q's , but I am just considering a leaflet especially about what I have tracked since 1983 very closely, and metered, since there is such a large number of great installs to compare to.
Response to Jon Pierce
Jon,
You asked four questions. I'll do my best to answer them.
Q. "How small is a smaller home?"
A. In 2010, the average size of a new single-family home in the U.S. was 2,169 square feet. So any new home that is 2,000 square feet or smaller is smaller than average.
Q. "What is saved in upfront testing and engineering by simply demanding a loop-performance contract?"
A. I'm not sure how many ground-source heat pump contractors offer loop-performance contracts. It's possible that insisting on such a contract might increase the cost of the system. I can't imagine that insisting on such a contract would lower the cost of the system.
Q. "How engineering wide are the margins of application(s) as to the old considerations of single speed equipment divided in half ton incremental selection 1/2 to 5 compressor-tons, relative to balance points being 10 degrees at one home and 5 degrees at another with LOAD-MATCHING equipment?"
A. Please re-phrase the question in conventional English.
Q. "What about the history being able to really track simple low cost pre-building design builds vs. ?"
A. I don't know, Jon. What about it?
200 miles from the Freudian Slip?
Martin,
It sounds like the Energy Nerd sees Canada's perm rate as low - like a poly - but we like to think our border is open enough to breathe!
A great article by the way.
Regards,
Greg Labbe
Response to Greg Labbe
Greg,
Thanks -- the slip has been fixed. (I type the word "barrier" 24 times a day, and sometimes my fingers type automatically, as soon as I press "b".)
Rephrased: Saving on performance guarrantees bests
A. Please re-phrase the question in conventional English:
A)JP)
If one takes a lot of time and second and third visits desiging with (I have 'em) pet-balance points and loops only ending up at under Energy Star minimal 32f Entering GTHtP's
then
why not just size to a guaranteed 34f or more Ground Loop in contracts, to SAVE MONEY (causing less carbon, ultimately) after recovering in a year or three such an upsell, yielding greatest ROI's afterwards? (like better insulation , but stopping at diminishing returns)
Why not -when practical, avoid incremental selection as towards presumptions of one customer wanting "our" balance points with supplemental heat vs. a customer who frequently might want to leave supplemental heat off?
-
Since for three decades 3-Staging with Dual Compressors: , Can be mostly avoided with a Variable GT now available;
and in small homes
- it is the instant hot water of 30,000 btuh that may be more important with GT HVAC-Reclaim in cooling to the HW tank:100%, loop pumps/well pump off for that 20 minutes recovery.
(a little larger ground loop, much larger $ ROI'sin years to follow) .
Q. "What about the history being able to really track simple low cost pre-building design builds vs. ?"
A. I don't know, Jon. What about it?
A)JP)
Why not have that Q of yours in another post for others to list the many ways for over a decade practical tracking has been done? and especially with log file keeping and sensors OEM installed since 2007 residentially to cover those other bloges of comparrisons needed.
Almost every one of my installations have meters on the equipment since 1993.
We can see Earth-Heat of any transfer, is really just GEO-Thermal and I thiink if 76% or so is 100% sustainable-renewable as it is, why not compel the action of bests with more questions in posts about what ALL of the GeoThermal or now Airsource and Hot Water on demand can inclusive compare to? historically documented- and by so many in just this 'hot bed state' of mine as well.
thanks for this
I was just poking around for a little light reading to send a few potential clients. This will do the trick quite nicely.
Response to Robert Swinburne
Robert,
I'm glad that my 2013 article is still valuable.
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