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3 Answers

ERV and humidity

This is more for my own curiosity.

I've read that ERV's are generally suggested for warm humid climates and I've also read they can cause humidity levels to rise within a home. My understanding is that with an ERV some moisture is transferred from the stream that contains higher levels of moisture to the stream that contains less. Does the system medium look to balance the amount of humidity between both streams?

Example, Stream A is at 40% RH , Stream B is at 20% RH, ~10% is transferred from A to B where both end up at ~30% RH)

Asked By Chris M | Aug 25 16
0 Answers

How to grout concrete block wall?

My foundation stem wall for a raised-floor house is four courses high, made of 8x8x16 concrete blocks with #4 vertical rebars every 4 feet and a #5 rebar in the bond beam top course. I've installed grout stop over the unreinforced vertical cells. After two days of searching, I haven't found any step-by-step instructions on how to grout the reinforced cores and the bond beam, but I have gleaned a few tips to supplement what seems fairly obvious about the procedure. Does the following overlook anything important?

Asked By Jeff Cooper | Aug 27 16
7 Answers

DIY heat recovery and ventilation question

Ok..so it's been a while. We completely destroyed and then rebuilt our 1800s house and aside from some trim and exterior improvements...we have been comfortably living in it now for over a year with many thanks from this site. We used the cut and cobble insulation system combined with blow in with a mooney wall to keep our house very energy efficient. Even in the deep cold of winter our heat bills are below 100 bucks in a 1400 square foot house built over 135 years ago.

Asked By Geoffrey Cook | Aug 24 16
1 Answer

New PHIUS Standard & Small Homes

Is it true that the new PHIUS standard utilizing WUFI, has a bias towards small houses (under 1,000 sqft)?

Running the software calcs shows that the same small home, with the same R-Values, will FAIL to make the PH Standard while increasing the square footage and keeping all other variables the same, will PASS the PH Standard. Even when the R-Values were increased on the small house, it still failed to make the PH standard.

So it seems that the software has some type of "bias" built in for smaller homes?

Could it be a glitch, since the software is so new or is it something else?

Asked By Peter L | Aug 27 16
1 Answer

Can you use rigid insulation only? Exterior wall in zone 1

We are enclosing a screened porch, reinforcing exterior walls on a 1969 trailer and then we plan on putting up rigid insulation over plywood sheathing and existing aluminum

Asked By Jennifer Earp | Aug 27 16
2 Answers

Condensation on soffits after painting

I have a split-level house that has an second-floor overhang with soffits where the a/c ducts terminate to supply the 2nd floor with a/c and heat. We repainted the exterior of the house a week ago and now exterior condensation is forming on the soffits directly below the a/c vents. I've lived in the house for 10 years and we never had any issue like this that I'm aware of. This condensation keeps the paint from drying/curing. What should I do?

Asked By Buzz Mershon | Aug 27 16
4 Answers

Options to make space for exterior insulation

This is my first post so thanks in advance for any input. I’m finalizing the plans for our new home with in Kentucky, and I’m talking through the option of adding 2” of Roxul Comfortboard on the outside of ZIP wall sheathing with the builder. He has never done this before, and one of the objections he is raising is that it would require making the foundation/basement walls 2” thicker to make room for this since we are already planning on a brick cladding.

Asked By Brad White | Aug 26 16
9 Answers

Insulating a finished garage with unvented cathedral ceiling

Hello -

I am hoping for any input/advice about insulating my garage, which I'm in the process of finishing. The details are:

This is a 20 x 20 garage, uninsulated concrete slab floor with an epoxy finish on it. Unvented roof which will have drywall up to the peak. The walls are ordinary 2x4, the ceiling is 2x6. The garage has several windows, all double-page argon/low-E and a insulated garage door that seals surprisingly well (but it's still a garage door).

This is in Denver, CO zone 5.

Asked By Dave H | Aug 9 16
2 Answers

“Smooth” flex duct

I understand that flex duct is bad in most situations--it decreases blower efficiency and just generally impedes air flow. That said, for a longish (25ft) run of 6" duct, I wonder if it wouldn't be okay to use one of the 'smooth wall' plastic ducts on the market (see http://www.flexaust.com/product/grass-collection-vacuum-hose/) for a good example of what I'm looking at. This would be in a relatively low-pressure type of situation (Minotair hybrid HVAC system installation).

Asked By Jonathan Nagar | Aug 26 16
6 Answers

Following up on the musty smell in our crawl space

Editor's note: This is a follow-up to a previous thread on GBA. The previous thread was Why do I have a musty mildew type smell in my conditioned crawl space?

Asked By Linda Larochelle | Aug 26 16
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