Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

The usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration:
Under the box labeled "More explanation," look for the words "File attachments."
Click that, and you should be able to attach a photo.

Thanks for joining the conversation!


0 Answers

Freeze risk for a heat pump water heater in an unconditioned garage

I have an unconditioned garage with a gas water heater in climate zone 5B. The garage is unconditioned, but insulated (R-15 whole wall, no slab edge or sub-slab insulation), and obviously has some exposed plumbing in it. Right now, the temperature in the garage doesn't get low enough to present a freeze risk, probably aided by the water heater's standing pilot light and hot metal flue. But if I replace it with a heat pump water heater, the unit's going to be continuously cooling the room, right?

Asked By Nathaniel G | Jan 31 15
1 Answer

Closed cell or open cell foam for rim joist in Climate zone 5A

I realize closed cell foam would provide a better R value, but which density of foam would the preferred choice to prevent condensation on the rim joist itself in our mixed climate zone?

Asked By Gary Brod | Jan 31 15
6 Answers

Radiant floor vs. minisplits?

I have a 800 sq. ft. home in Asheville, NC, and am looking to put on a 550 sq. ft. addition. I have been looking into all options of radiant floor heat vs mini splits for our heating and get stuck between preference and practicality. I am adding three floors with each floor being about 190 sq. ft.

Asked By Clayton Hufford | Jan 29 15
0 Answers

Does code require fireproof caulk around electrical boxes & light switches?

We had a blower door test on our house following a major renovation (ACH50 = 4.56 on a 1920s Bungalow, Zone 2A). Several leaks identified, along with my plan to airseal them:

1) Electrical boxes & light switches (photo attached) - Caulk the gap between the electrical box & drywall, add a foam gasket behind trim plate, caulk plate to wall (on inside) & install child safety plugs in unused outlets

2) Base of interior door jams (photo attached) - Caulk

3) Exterior door weatherstripping (copper) - Bend back the copper for a more rigid fit

Asked By Robert Hallenbeck | Jan 31 15
15 Answers

HRV as sole means of controlling interior humidity - fail!

I've got one year of data in my new house, and I'm not pleased with the HRV's ability to lower interior relative humidity. I'm hoping folks with more experience can clarify which is more flawed: my mechanicals or my expectations.

Asked By Andy Chappell-Dick | Jan 4 15
1 Answer

Is power washing a 20 year old cypress siding house with a vinegar & water solution effective?

I am looking for ecological solutions to power wash the cypress siding on my 20 year old house. Using vinegar was suggested to me ~ has anyone had success with using vinegar, or can anyone suggest other ecological solutions?

Asked By Shannon Dancy | Jan 29 15
2 Answers

Placement and selection of the elusive barrier.

Asking for opinions. I'm in zone 7/8. My plan is for a one story earth bermed home set about 3 feet below grade, bermed to varying heights of 3 to 6 feet. Typical treated lumber wall but with 12" double stud walls with dense pack cellulose and 2 inch xps exterior with taped seams.The exterior would then be wrapped with heavy poly as per the PWF specs. My question is " Can I continue the poly sheet protecting the foundation up to cover the entire exterior wall as an air, water, vapor barrier. I would have no barrier on the interior wall since the idea is to dry the walls to the inside.

Asked By Thomas Hoffmann | Jan 31 15
7 Answers

Code Required - Electric Resistance Heater

Zone 4 - My building code department is requiring a heat source in all the bedrooms even though I am building a super air tight, super insulated home (way above code). I have a ductless mini split in the adjacent room and I leave my doors open but the building dept still wants to see a "heating source" in that room.

Makes no sense to install another minisplit unit in a small room so I want to get past code inspection by installing an electrical resistance heater. What is a good brand/type to install? Can I just install one of those wall mounted fireplace units that put out resistant heat?

Asked By Peter L | Jan 31 15
7 Answers

Euro style inswing windows & lessons learned

This is kind of an interior design question, but I am wondering what people's experience has been with these inswing windows? Specifically in living rooms and bedrooms wherein the inswing of the window can cause problems with furniture placement.

I am tempted to place windows at 36" high in living room/bedroom areas simply due to ease of furniture placement. If it's that high (and wider to compensate), it won't ever hit the back of a sofa or end table or whatever. Ditto for bedroom furniture such as a nightstand, desk, or dresser.

Any lessons learned would be appreciated.

Asked By Lisa O'Donnell | Jan 5 14
4 Answers

Heat pump water heater for radiant floor heat?

I have a 190 sq ft basement pad for an addition that I would like to put in floor heat. Have been looking at various top of the line gas water heaters, but am curious about heat pump water heaters. Several good ones on the market specifically GE GeoSpring™ and Stiebel Eltron Accelera® 300.
Because of slow recover seems an 80 gallon tank would be best but just can't find much info on whether one of these would be good for radiant floor heat and my domestic water. I live in Asheville, NC a zone 3 climate zone, so winter do get below 20 F in Jan and Feb.

Any thoughts or experience here?

Asked By Clayton Hufford | Jan 31 15
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!