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7 Answers

Small super insulated house - grid tied or off grid?

Where is the $$ line today between grid tied and off grid? I’m talking to a retired nurse with a limited budget who wants to build an 800 SF, super insulated net zero home on a lot (in NH) which requires a long driveway (and therefore an expensive connection to the grid) . She will have low electrical plug loads. Does the Tesla Powerwall battery influence the decision?

Asked By Bob Irving | May 16 15
0 Answers

What new idea would you like to see pursued?

ORNL is running a competition for new ideas for building energy efficiency technologies. You can submit an idea or read and vote or comment on ideas that have been submitted. You have through the end of May to submit new ideas.


The leading idea right now is vacuum insulated panels that are plumbed to a central vacuum pump rather than being permanently sealed. Do you have a better idea than that?

Guidelines for ideas to submit, from their FAQ:
Innovative technical design ideas that are not yet prototyped

Asked By Charlie Sullivan | May 19 15
1 Answer

How do I remove hydrostatic water pressure?

We purchased a home in central Missouri recently and we see evidence of slab/footing movement. The home is built halfway down a hill. It has a walkout basement with a large patio off the walkout. The downhill side of the walkout has risen about an inch. There is a perimeter drain along the front and down the downhill side until the foundation wall begins the step down toward the patio, so it covers the front and half of one side. If I extend the drain to the patio will that help with the water pressure? I need to mention that the soil is clay.

Asked By John Beavers | May 19 15
14 Answers

Minisplit heat pump sizing issue

Hi All,

I am hoping someone can point me in the right direction.
We are thinking to add mini split ductless heat pumps to our existing 1550 sf raised ranch in Manchester NH. The house has good insulation for the age with R50 in the attic and 15 year old windows. It has 2x4 walls so not sure about R-value there. Currently have hot water baseboard heating system with 25 year old oil fired boiler and our oil consumption averages about 450 gal / year.

Asked By Alex Frost | May 13 15
6 Answers

CARB2 Kitchen Cabinets - Formaldehyde

Hi all, Last year we did a kitchen remodel (in California) and my cabinets are CARB2 compliant. I know this because I had some of the plywood independently tested. Post remodel we did an air test (sealed off from the rest of the home) and I'm getting a 150ppb reading for Formaldehyde. I'm dumbfounded by how this happening. Is it possible for CARB compliant cabinets to off gas this much Formaldehyde. Any ideas what else could be driving this? Thanks!

Asked By Mike Miller | May 17 15
1 Answer

How to finish basement window

My windows have a frame with recessed sides and top. How do i finish, with drywall or wood?

Asked By John Kroeker | May 19 15
3 Answers

We live in an 1895-converted carriage house with an cold damp basement

We live in an 1895-converted carriage house with an cold damp basement made of field stone. We removed mold in the fall and now have the experience of a basement with an average temp of 36 degrees this past winter. SPF was suggested.

We understand EPA is in the midst of looking at long-term outgassing (suggested in a 2011 GBA article), but does not have any answer yet. There was a comment that some chemicals currently used MIGHT be banned in the future....but what facts can a homewowner use to determine whether or not SPF is safe long-term at this time?

Asked By Sandra Thomas | May 18 15
2 Answers

The "Perfect Wall" for Conversion Van in Warm/Humid Weather

After thinking about the "Perfect Wall" for an upcoming Van Conversion project, my goal is to use non-toxic, organic and sustainable materials. The base of the van is metal. As for layers I've considered the following starting from metal (inner layer) to floor (outer layer).

1. Lizard Skin Sound Control (Sound/Radiant Barrier)
2. Lizard Ceramic Insulation and/or PermaLoft Wool (Insulation)
3. Recycled Polyethylene (Moisture Barrier)

Asked By Sydney Jamila | May 18 15
3 Answers

How apply wallboard to sloping foil-faced polyiso?

In a Green Building Advisor discussion titled "Proper wall to attach rigid foam to the inside of the wall?" on Nov 17, 2014 asking about applying drywall on the interior side installed foil faced polyisocyanurate Martin Holladay responded:

Asked By Anthony Vogel | May 19 15
16 Answers

Budget concern: Better to buy the R-10 windows with less-great walls?

A budget crunch forces some tough decisions. Most of the bidders prefer using 2x6s instead of the double stud wall, and using American R-2.5 to 3 windows over the European R-10 ones. My general knowledge is that heat always moves to warm up what is cold, therefore keeping our R-10 windows in the design seems like the place to spend our money. This would mean backing down to an overall R-22 wall (2x6s 24" oc, exterior 1.5" Zip System and another 1" of rigid insulation, well sealed batt or rock wool in the cavity).

Asked By Will Gerstmyer | May 13 15
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