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15 Answers

How much are mini-splits really affected by altitude?

Hello -

I'm sizing a heat pump mini-split for my 20x20 garage, which has been pretty well air sealed and insulated with closed cell foam. I've had a series of installers out and the recommendations were all over the place, ranging from 12k to 18k BTU, and from $3k to $12k.

Two of the companies actually bothered to do a load calculation, and I tried it online as well - but those numbers had a broad range, too.

In General questions | Asked By Dave H | Sep 22 16

2 Answers

Use poly with Roxul (on ceiling)?

Hello,
I am zone 4A, about 40 miles south of St Louis, Missouri. I am gutting my 1937 bungalow. It has two attic bedrooms (so it is a 1.5 story home), and it has an unvented attic. I want to leave it unvented, because of the multiple dormers. Eventually, the roof will be insulated with closed cell foam, but that will be a long ways off. I am not gutting the upstairs for quite a while. I have gutted the first floor and insulated the walls with Roxul R15 rock wool. I just ordered Roxul R30 to put in the first floor ceilings.

In General questions | Asked By Lonnie Sullivan | Sep 26 16

17 Answers

Quest for EPS

Finding extremely limited offering of eps rigid insulation in my region (upstate ny, north of Utica).
In my manufacturer search I found a product made by Cellofoam called Polyshield. They describe it as a sheathing product and it's eps with polymeric facers on both sides added for strength.
Is anyone familiar with this product?

In Green products and materials | Asked By Daniel F. Vellone | Sep 20 16

1 Answer

Video that aired on PBS: best practices for flange at bottom of window?

Hello,

This is a video (link below) from the MN Building Performance Association, which aired as a half-hour special on PBS here in late 2015, I believe.
I am wondering if I'm misunderstanding something about proper flashing at the flange at the bottom of the new window that's being installed here. About six and a half minutes into this video, the installation gets going. The installer flashes properly before install, which I believe was the point of the new install, but then also tapes over the bottom flange. Is this correct?

In General questions | Asked By Minneapolis Disaster, 6B | Sep 26 16

7 Answers

Supplier for small registers and boots for ducted minisplit?

Hi all,

I have a completed manual J, S, D, & T. Now I have to find the different parts an pieces.

Because of the small loads in the house, the ducts and fittings are smaller than what I see in stock at the local big box suppliers. For example, I need 4x4 and 4x6 duct boots and register grilles. Where can I find those size fittings?

In Green products and materials | Asked By Clay Whitenack | Sep 26 16

5 Answers

Insulating underneath wood shingles underneath asphalt shingles

Hello!

I've done my research and read quite a few relevant posts and articles here, but I couldn't find an exact match for my situation.

Legend has it that my home was built in 1876 in Philadelphia and moved here to Harrisburg via barge sometime after that. I'm in Climate Zone 5.

My wife and I are looking to build an insulated cathedral ceiling. Yes, I've read the wonderful GBA article :)

In GBA Pro help | Asked By Drew Buglione | Sep 20 16

0 Answers

I'll be speaking at the EEBA conference tomorrow

GBA readers in Texas may be interested in attending the annual conference of the Energy and Environmental Building Association (EEBA), which starts tomorrow in Frisco, Texas. I'll be giving a presentation there tomorrow morning on cathedral ceilings.

EEBA is a great group -- they have been promoting energy-efficient construction practices since the 1980s. I hope to see some GBA readers there.

For more information, check out the conference web site.

In General questions | Asked By Martin Holladay, GBA Advisor | Sep 26 16

4 Answers

Sanity check on energy efficient window pricing

I'm pricing out energy efficient windows, and am wondering if the quotes that I'm receiving are typical. I'm looking at white, triple glazed, low-e, argon or krypton filled fiberglass new-construction casements with no grids. I've received quotes from two Canadian manufacturers that are both $47/ sq. ft, uninstalled. Does that seem in-line with other people's experience buying windows?

I'm aware that vinyl windows would be cheaper, and that double pane windows probably have better ROI. Having a firmer idea of pricing will help with that math for my house.

--John

In Green products and materials | Asked By John Ranson | Sep 22 16

9 Answers

Condensation on plexiglass?

Hi,

In fall-winter-spring, I have lots of condensation on my double-pane windows. After reading multiple sources on the Internet stating that condensation does not form on acrylic, I fastened a plexiglass sheet on a window to test. I lowered the double-cell cellular shades for the night.

This morning, I realized that the test failed - there was fogging on the bottom part (but no droplets). I guess I read the wrong sources or I did something wrong.

Which one is it?

Thanks for your help!

In General questions | Asked By Marc Delisle | Sep 25 16

3 Answers

Could a heat pump unit be used to heat a crawl space that is closed in?

I'm thinking about having a heat pump system added to my mobile home. The home is about 1500 sq. ft., with a crawl space about 3 1/2 ft from slab to bottom of the mobile home.
This would help heat the floor above and allow me from leaving my home unoccupied for a time during the winter and only have the heaters keep temps around 56.
Well above 35 degrees.

Could this be done?

In General questions | Asked By Leonard Klinger | Sep 25 16

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