Heya! I've been lurking for a while on the various formats that came together for the HEP Forum. Haven't posted/contributed for a while due to crazy busy schedule (that's good, right!?!)

I'm working on a series of blog articles on Exterior Insulation & Deep Energy Retrofits, specifically in cold climates.

Just to give you some background, I've worked with clients to design and carry out DERs, specified some others, and am now working on a demonstration project for NZE renovations, and I sit on two technical working groups in Canada focussed on retrofits, NZE and exterior insulation optimization.

The articles will start with the projects that I'm involved with, but I want to broaden the scope by getting more information out there on who's doing what, how cost-effective different approaches are, if costs and approaches vary regionally, and how do we improve performance and cost effectiveness. In addition, there will be articles on tackling the actual details: roof overhangs, connection to existing house, door/window openings, moisture management, etc.

If you have worked, or are working, on Deep Energy Retrofits with exterior insulation, please give me a shout so we can set up an interview time. Or you can drop a line here.

If you've got any questions or concerns you want to see addressed in the blog articles, jump into the discussion here.

I'll post the articles in HEP Forum as I publish them.


ps you can find me at Bfreehomes and Blue House Energy

Tags: DERs, NZE, climate, cold, deep, energy, exterior, insulation, retrofits

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I help with 1908 32 unit apt building with 3 layers of brick walls and a steam heating system.    Changed the one bed room to 3 bedrooms, made windows smaller glued and used concrete screws to fasten 1/2 structural insulated panels 3.5' to all walls  up to soffit trim.   Used a light weight concrete board/1.5" foam over the stone foundation.  I put in air type heat pumps with air handlers 800 sf/ton  some had lifts of 45 feet.  The city was a complete pain.  Then the history of building - style got to be a big thing stopped work for years.  

Building America has funded quite a bit of work in Deep Energy Retrofits, including in cold climates. Quick way to look up reports is in the Building America Solution Center, click "Library" on the left nav bar, then type in your search term. I typed in "Deep Energy Retrofits" and got 26 reports. Check it out: https://basc.pnnl.gov/library?search_api_views_fulltext=deep+energy...

Good luck!

Thanks Eric, yes, great resource. I'mlooking for unpublished stuff that we can add to the pot.

Hi Shawna, 

I work as an auditor and energy advisor for the Community Energy Challenge (CEC) in Bellingham, WA. The CEC is an efficiency program under the Opportunity Council and affiliated with the Building Performance Center.

For the past two years, I have been managing a "Toward Net Zero Energy" pilot project focusing on DERs in the Pacific Northwest. This pilot has facilitated 3 retrofit projects here in Bellingham, all incorporating multiple measures including beyond-code insulation details. These projects represent a variety of DER approaches: one was completed from the building exterior employing exterior cork insulation; another from the building interior employing a double stud wall, new air and vapor smart layer, and densepack cellulose and rock wool batts; and a third which is interesting mostly because it represents how a comprehensive "retrofit" can sometimes become more of a "rebuild." 

I haven't completed a full analysis of costs and hours on these projects, but I'm happy to share some details and unofficial outcomes. 

Thanks Lee! Sounds like an interesting pilot. Cork insulation is a new one for me.

I recently worked on a DER of a 63,000 SF Army Barracks in Northern California that used exterior insulation. We've achieved significant heating reductions.

Hey Shawna,

We've done one exterior insulation DER. The energy results are frankly disappointing, it's using over 1/3 more per square foot than a much shallower retrofit we did. Here are the case studies:



IMHO exterior insulation for retrofits doesn't make much sense, but it is good to run a load calc to find out. Your climate may be cold enough or the home type may make sense. Generally I'd put more money in attic and basement air sealing and buying higher end HVAC to electrify the house.

You can see from the 1918 home that it worked out well. That home uses less energy than 93% of Ohio homes in the DOE Building Performance Database. And it's 100 years old next year.

Jon Harrod of Snug Planet has come to a similar conclusion about DERs, BTW. Also, of the 1000 Home Challenge only 30 have certified. The 70% bar is likely too high. 

We should be talking A LOT about electrification. It usually drops site usage 30-60%. With renewable power all we have to account for is 3-10% line losses, so site energy is not a bad proxy for reality.

Don't know if that helps you, but fingers crossed it spurs conversation.

PS You can watch live energy use of the TREE House here: http://egauge13275.egaug.es/

Nate, I gotta say one disappointing exterior insulation DER is not a very strong data point.

There is no single way of approaching a DER, and not every approach will work in all climate zones or even with all housing types.There is no silver bullet solution. But an exterior insulation package is one way, and I'm doing a deep dive.

The problem is this: there is very little in terms of available data. NRCan estimates that only 4% of all EnerGuide for Existing Houses upgrades have included an exterior insulation package. Now it's important to point out that the ERS database is skewed by the fact that in Ontario, and other parts of the country, the EnerGuide program was, for several years, tied to stupidly designed rebate packages that turned the 'whole house energy efficiency' goal into a furnace swap-out program. 

Here's part of my experience, backed up by some recent research done by Gary Proskiw in Winnipeg, MB:

An exterior insulation job is not going to give you great returns ***unless*** the house is a good candidate for cladding replacement. And then, as Gary's study shows, the cost of R15 exterior is less than 10% of the total job cost. The opportunity to create a well-sealed, insulated exterior air barrier that ties in at foundation and roof solves all sorts of problems. Creates a few too, but those are not insurmountable: details for overhangs, details for tie-ins at foundations.

If we can do away with the cost of stripping the existing siding and do a 'build over' envelope, a la energiesprong (Netherlands), we get rid of a large chunk of the cost of a cladding replacement, and can put that back into a better solution that includes better insulation, air sealing, new windows and modular HVAC. (Side note: NRCan's PEER program saw an air leakage reduction from 7.5 to 1 ACH@50Pa on their gen.1 version, with an additional R24-ish, I think, don't have the info in front of my right now.)

I've got lots of fishing lines out there on this one, lots of interest, some experience and case studies, and some healthy skepticism. Will be sharing what I learn as it comes into reasonable shape.

One data point is all I've got! =) But mixed with another project that's much less deep using much less energy, and things get more interesting.

If siding is being replaced, I think there's an argument to be made. It's good to dig into these things. 

One thing I'd be curious about, is what do you to with a brick building? 

PS We modeled exo-insulation on my house, it saved $250/year. About 250-300 therms.

George Brown College has done some excellent research on outboard insulation on brick buildings. I know the folks in the program, just have to reach out to them to get the info (it's published somewhere, but their site is a difficult one to navigate).

See what cheap gas does to your ROI? ;-)

That's the fuel price bias that you need to acknowledge.

Try expensive electricity or oil as your fuel source. Return gets way better.

"That's the fuel price bias that you need to acknowledge."

"Try expensive electricity or oil as your fuel source. Return gets way better."

You say we have fuel bias, then immediately show your own? 

Shawna, our projects have 50 to 250 year paybacks. Our fuel bias isn't about payback, it's about sustainability and long term customer financial risk. It is also about not allocating client resources on very expensive items of dubious benefit. It is about solving THEIR problems, for THEIR budget.

Exo is simply not feasible to sell to consumers, not at a scale that supports driving market transformation we desperately need. What you are doing actually HARMS that goal. It'll scare people away.

What we are currently doing is a huge lift that others don't seem able to duplicate. We've done exo, and it's value is tiny and very specific. You think I'm wrong? Go out and sell 10 projects without any free money, prove me wrong.

We've done it twice. Once was an experiment, the other was because they got free foam board. They were both hard and unprofitable, and energy savings was unimpressive relative to our other projects. We can save lots of energy without this.

Even if you can deploy once or twice without free stuff, I bet you can't figure out a way to scale. WE HAVE TO DO MILLIONS OF HOUSES, NOT THIRTY! Even if you figure out a way to sell this, getting it done properly is very risky, expensive, and of extremely dubious benefit. 

ROI for energy efficiency is a bald faced lie used to falsely motivate people to act. It sets up false expectations and puts pressure on design to exclude necessary items because they "don't cost justify."

We must move away from including this design perverting narrative. What's ROI on your kids not getting asthma? 

Here's an idea - design to what the homeowner and the house need. Make houses great, and don't let the pursuit of perfection be the enemy of great. Make the clients really happy so you get great reviews, track your outcomes so you know what is possible, put client interests ahead of your romantic notions, 

and provide a path other's can sell. If you don't have all those things, you aren't helping. 

Move people to electricity. Move them to renewables.  Let that be your basis for design. 

Hold up there, Tedd.

We're on the same team.

And we're singing from the same hymn book.

Best option for the client. That's the title, right?

Move people off fossil fuels and onto renewables, Right?

Tracking and monitoring to actually SEE how we're improving performance. Right?

I use the term ROI because it's better than simply payback or TCR. If we had decent metrics and calculators for Non Energy Benefits, I'd use that in an instant.

And I'm trying to push the ROI period out past 15 years in the projects I'm involved with, so we can look at the bigger picture and do right by our clients.

I'd like to see the documentation that you're basing your outright dismissal of exo on. I say that without prejudice. I want all sides of the discussion on this.

And I'll state again: I'm not suggesting that exo is the ONE AND ONLY SOLUTION that you must use. I'm researching it as a valid option for the industry to use for a decent portion of the millions of houses that we can retrofit vs. replace.

Please, it's all part of the path. You, me, Nate, the rest of the industry, we don't know it all. I have the chance to do a deep dive into this particular approach across several markets. Let's see what you and other industry players have to say who are NOT using 'free' money to carry out exo, find out what the gaps in their analysis are (ie - did you track that performance?) and have some more informed discussion about it it's viability as an option for DERs.


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