Just had a convo with a cold climate builder who said he has had concerns about the viability of the continuity of the air/vapour barrier created by using high-density foam in frame walls where budget dictates non-kiln-dried framing materials. Once the foam has set, and the wood starts to dry out, he has seen the studs twist and cup and significant cracks develop at the junction between the studs and the foam, and in some cases throughout the foam itself.
Although he didn’t tell me if he’d done a before/after blower door test to see what the delta, his concern was enough to make him change products. He now uses high density foam on all non-framed walls where there is no issue with movement or shrinkage and the more flexible low density foam on framed walls. He’s willing to take the hit on the lower insulation value and the additional vapour barrier requirement.
I hadn’t bumped into this issue before and wonder if there are more people who have experienced this problem, and if so, is there any documentation, and if not, do you think there should be?
edit to original post:
…apart from installation issues, I mean. Have asked a few questions of one Net Zero builder who is using high-density foam and he pointed to installation QA/QC problems with +2″ layers being sprayed, or layers are being sprayed without enough setting time between them if pulling and cracking are issues. He noted one incidence where a crap installation at the rim joists resulted in shrinkage and pulling that left gaps of 1 to 1.5 inches!
He didn’t see much of an issue with air barrier being compromised, because spray foam would be in contact with sheathing and that is stable. I have a few phone calls with other Net Zero/Low Energy builders this week that are unrelated to this topic, but I know they have experience with high density foam, so I’ll ask some more questions and report back on what I find.
NREL has this cool database (that needs populating!!).
It’s called the Technology Performance Exchange. You sign in as a user or a contributor, and you have access to performance data for 17 different types of technologies, from lamp ballasts to inverters, with more categories to come.
If you’re a user, you get to search through and compare energy performance data on up to 4 different products in the category, allowing you to evaluate energy and cost savings in energy simulations. Manufacturers, third party verifiers and ‘contributing evaluators’ are allowed to populate the database.
It’s a little spotty now, in terms of data available in all categories, but my quick wheel through it showed up a very well-populated PV category: 10,780 entries. I was able to narrow the search results by system or module, then by module efficiency, rated power, cell material, total # of cells, nominal operating temp and three different performance coefficients.
Other categories, like ‘boilers’ have lots of placeholder entries (ie, brand, product line and model numbers), but have yet to be fully populated with performance data.
This is a big project, and will be über-useful when more completely populated. Spread the word!
Deep Energy Retrofits , Energy Efficient Stuff , Low Energy Housing
Invited to present at WREN (World Renewable Energy Network) conference
The WREN Conference invitation came because I was invited to write a chapter in a book on Sustainable Buildings back in 2012. The book (Sustainability, Energy and Architecture: Case Studies in Realizing Green Buildings) was published last year (http://bit.ly/OXVl0k). The chapter I wrote was ‘Deep Green and Comfortable’, focussing on energy savings to be had by carrying out deep energy retrofits on existing houses.
The paper I’m writing for the conference expands somewhat on that idea, and looks at the missing part in many discussions that I’ve had in the field, with clients, renovators, lenders and other stakeholders: proving the value of deep energy retrofits. Not just for the current homeowner, but for future homeowners and for the municipality/community.
The idea came out of one particularly frustrating discussion with a potential contractor for one of my renovation clients. Note that this was a contractor who was bidding on a job that had already been specified. The client wanted to stay in the 100 year old house (location was spectacular, structure was sound, a phased deep energy retrofit was completely reasonable option). We were recapping the details of phase 1, when the contractor put down his pen and calmly told (my) client that renovating was not the right option. That the cost was likely to be more than 30% of the appraised value of the house, and therefore not a good economic decision.
Then he continued, telling (my) client that their best bet was to go out to the suburbs and buy/build new.
This, I thought, was not cool. The client’s preference — to stay in the house, and the strategy we had landed on — to phase the retrofit over 5 years, was clearly articulated, with modelled energy reductions, projected fuel costs (they were on oil, we were looking at a heat pump after major envelope work) and rough order costings showing payback and ROI. Apparently that didn’t make much of a dint in the contractor’s view, even though he had been briefed on the project and asked to review the design program and ask me any questions before the meeting.
I wondered where he pulled the 30% figure from, politely. It was a ‘rule of thumb’, he told me. I didn’t ask where his thumb had been, but I did ask him to back up the rule of thumb with some concrete information, which never came — neither did the quote.
So then I started thinking about the inherent value of established neighbourhoods with infrastructure vs the cost of greenfield development, and then I started mashing that together with the value of the resources tied up in an existing house, and the cost of retrofit vs. the cost of new construction and I got all jumped up about research and proving the case for deep energy retrofits.
For your entertainment, I’ll be blogging bits and pieces on this over the next few months…WREN conference is in August.
Was rummaging around in a bunch of market research when I came across this item, from April 2013, which makes me shed many tears. Here’s the headline (go read the article if you want to cry, too):
Shelton Group Study Shows Decline in Energy-Efficient Product Purchases and Home Improvements.
I’m not weeping in angst because energy-saving habits have declined in the last three years. I’m weeping in frustration that the extent of what counts as ‘energy efficiency’ is so focused on minimal impact issues like replacing light bulbs and purchasing high-efficiency appliances, unplugging chargers and un-used appliances. Let’s look at the impact those ‘energy efficiency measures’ have on a relatively standard issue household.
I like the idea of LEDs and high-efficiency appliances and shutting off stuff you’re not using. Of course I do!!!!! So I’ve posted a bunch of info about energy efficient lighting options in the last few weeks. But those are band-aid solutions to real energy savings. It doesn’t change the amount of energy used in the house in a significant manner. It doesn’t change the financial load for the homeowner or renter. The telling part of the article is this statement: “and more than 40 percent of those who’ve actually done something are frustrated because they aren’t seeing the reduction they expected on their utility bills.”
No kidding.
In Canada, electronics and lighting account for 4 percent of overall household energy use. Appliances account for about 14 percent. Space and water heating account for 80 percent of the overall energy use. Eight-Oh. Four-fifths. Mostly All.
In the US, with a mixed bag of climate zones and space conditioning needs, appliances and lighting account for anywhere from 20 to 30 percent of the overall energy use. Space heating and cooling, and water heating accounts for 70 to 80 percent of the overall energy use. Still Mostly All, if you ask me.
What stands in the way of significant reductions in energy used for space conditioning and hot water usage? Like 50 to 90 percent reductions.
Off the top of my head…
- Not a silver bullet option offered at a big-box store
- Not easily packaged in a direct install program
- More expensive than a few cups of coffee
Simplistic, I know. The primary stumbling blocks are always cost and complexity. Low cost, simple measures are thought to be easier to accomplish. But are they? What if we took another look at measures that take the whole house into consideration and put big savings in small affordable phases? I’ll give some examples of what we’ve been looking at with our clients in the next few blog entries.
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