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1 Answer

Vapor Barrier when using Excel II as Air Barrier

We're retrofitting a bungalow in Toronto, we're using Excel II as an air barrier. We want a green product for a vapor barrier. What's the best product? Would it make sense to use a Blueskin VP as a house wrap?

Asked By Thomas Kaempfen | May 27 17
3 Answers

Insulation and R-values

I live in Edmonton, Alberta. I am remodeling a home and trying to figure out the R-value I want in the walls and attic. I have seen recommendations in building codes and on several websites.

I am trying to figure out the difference in efficiency and cost/savings of different R-values. Any charts that explain this would be helpful.

Please let me know if you know where these charts can be found.


Asked By User-6846735 | May 17 17
27 Answers

Fujitsu Heat Pumps cause weird sound in breaker box and exhaust fan


Weird issue I'm experiencing and this obviously isn't an electrical forum but I wondered if there was enough mini split installations here that someone else may have experienced this...

The weather is turning warmer in Zone 4A so I am turning out my Fujitsu mini split heat pump A/C for the first time since our house has been under construction, and I noticed a weird sound coming from my whispergreen bath fan. It is hard to describe, but it is like an electrical hum similar to a flourescent light ballast. The sound gets louder when you actually turn the fan on.

Asked By Clay Whitenack | Apr 17 17
13 Answers

Retrofit single ductless minisplit to cool entire upstairs

Hello, I'm a huge fan of this website, but I finally joined so that I could ask this specific question:

My wife and I own a 2000 sq-ft colonial built in 1962 in the Metro Detroit area (climate zone 5), with only baseboard heating--no central air. The first floor can be kept comfortable with a single wall-mounted AC unit and some fans to help circulate, but the upstairs is a bigger challenge. We've had several options quoted to provide some form of AC, but we're leaning strongly towards a ductless minisplit system.

Asked By Nathan Efrusy | May 9 17
12 Answers

How to prevent leakage through the range hood?

We are building a net zero house and are concerned that leakage thorough the range hood will be a major loss of conditioned air or gain of unconditioned air. Is there a device to install where the duct exits the house that will close tightly when the hood is not in use?

Asked By Courtney McCracken | Mar 6 17
3 Answers

Closed-cell spray foam and XPS: green or not?

I've posted several times on my pretty badly compromised attic. We live in a 50s ranch outside Chicago with a ceiling that has been butchered by can lights and an AC handler & ductwork. I feel the only reasonable solution is to move the conditioned envelope to the roof. I've debated and debated and debated this because the solutions are expensive, a pain to implement, and now it appears environmentally questionable.

Asked By Brian Gray | May 7 17
4 Answers

Attic air sealing with tape?

I have a 1926 Cape in Seattle, WA (zone 4C) and the attic is in desperate need of insulation and air sealing (at least the half that I can reach). The ceiling and walls below are plaster and lathe and the insulation shows little darkening from the ceiling, just from the penetrations. The walls in the upstairs are drywall.

Asked By Kathryn Oseen-Senda | May 6 17
15 Answers

Cape Cod attic — cellulose machine

My finished attic in my cape cod has terrible temperature regulation up here in central Maine. So far I've put 1 inch foam between the floor joists sealed the gap with foam. I've also spent days air ceiling the upper attic. Next step is for me to dense pack the sloped ceiling, which is made up of 2x8 rafters. I'll be using accuvent cathedral ceiling extensions to provide ventilation. The sloped ceiling is about 5.5 feet long so I'll be connecting two of the vents together and stapling at either side. The house is about 34 feet long and I have slopes on either side.

Asked By SciFiJock | Apr 25 17
4 Answers

Rockwool from international suppliers (China)

It seems that a simple internet search turns up hundreds of sources of rockwool from China. This seems like a product which is dominated by a few (1?) suppliers here in North America. With some sleuthing, it seems like something that could be had for a lot less money per inch... I understand the possible downsides of unknown suppliers, but this seems like a widely used product outside of the NA market.

I also remember horror stories about Chinese drywall and laminate flooring. I am only considering this for subslab and exterior foundation insulation.

Asked By Ethan T | May 3 17
5 Answers


This product seems to have superior qualities to ICF (in terms of embodied energy, blow outs, and material stability). I do not see much discussion of it here on GBA. My concrete guy says just pour the foundation and footing walls and forget about ICF (or, I assume, Nexcem, though I haven't mentioned this specifically). When all you have is a hammer, everything looks like a nail...

Asked By Ethan T ; Climate Zone 5A ; ~6000HDD | May 3 17
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