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17 Answers

Radiant hydronic heating, embedded in slab, or over slab?

This is perhaps a very stupid question with an obvious answer, but..

Are there any numbers of how much more efficient is it to embed pipes for hydronic radiant heating in the slab, vs laying them ON the slab?

Also, as a rule of thumb, doing it in slab should be less expensive?

In Energy efficiency and durability | Asked By davor radman | Jan 27 17
20 Answers

Best cold climate exterior insulation assembly

Hello GBAers,

Long time reader, first time poster here. I have huge gratitude for this resource, and I've finally become a member.

We started on a PassiveHouse retro-fit journey quite a while ago, and we really need to finish- I'm gearing up to do that now.

Our architect spec'd 6" of polyiso on the exterior, fastened with 1x4 battens to which siding will be fastened, and which will also serve as a ventilated rain screen.

In Green building techniques | Asked By Gerald Pehl | Feb 9 17
5 Answers

Flash & batt insulation in Climate Zone 5

I would like to insulate a 2x6 wall cavity with a combination of either EPS or XPS and Roxul Mineral Wool - Can someone please let me know what thickness of FOAM would provide the best R-Value?

Mark Kozlowski
Nelson, BC

In Energy efficiency and durability | Asked By Mark Kozlowski | Feb 16 17
4 Answers

Open-cell spray foam wall insulation

Hi there,

I was doing consulting on a heating system in a new home this morning and brought up insulation as a subject of the heat loss calculation.
It was mentioned that they are going to be spraying open cell six inches thick in the wall bays. The house has 2 inches of styrofoam for the stucco on the outside. Next they have areas where there is a layer of tar paper or some wrap and then wood. Other areas the brick structure was retained.

In Green building techniques | Asked By Moe Hirsch | Feb 15 17
3 Answers

Super slim LED option

I have been looking at replacing my canned lights in the ceiling and considering two options. Unfortunately, cove lights, pendant lights or other options are not popular with my spouse.

In Energy efficiency and durability | Asked By Stan Weinstein | Feb 14 17
5 Answers

What are my options for fastening R-40+ rigid insulation on exposed rafters?

I have 2x10 rafters which I would like to leave exposed. My idea is to put T&G 1x's above the rafters.
On top of the T&G I plan on stacking rigid insulation (R-40 min.)
My question is regarding screwing OSB on top of the rigid foam all the way through to the rafters. Other than using 8", 10", 12" long screws (depending on the type of rigid foam) is there a different way to fasten this together?

In Green building techniques | Asked By Dave-OH | Feb 15 17
8 Answers

Radon fan location: outside via drain tile?

Per the oft cited recommendation, we installed a passive radon pipe in our home during construction. It's piped off the foundation Form-A-Drain and incorporates a top of the house area with electrical circuit and enclosure for the radon fan. We are now at the point where it probably makes sense to install that fan. In fact the fan is here ready to be plumbed in. (I have good reason to believe the passive radon pipe vent works, at least to some degree; certain times of the year you can see frozen water vapor near its output.)

In General questions | Asked By Andrew Bater | Feb 14 17
8 Answers

Insulation contractor recommends open-cell foam for cathedral ceiling

Hi - we are building a new home where the great room section has a cathedral ceiling with dormers on each side. We are planning on spray foaming the underside side of the roof deck, and the insulation contractor is suggesting open cell foam because if the roof ever leaked with closed cell foam, it would go undetected and the roof would rot. We are in climate zone 4A and we used ZIP roof sheathing with shingles applied directly to the ZIP. I would appreciate any input on this.


In Green building techniques | Asked By Brad White | Feb 9 17
6 Answers

Whole house dehumidifier - where to install?

I am currently building a 2 story, 5400 sq ft home in Alabama where humidity is often high. We will install a whole house dehumidifier ("WHD") as part of the HVAC system. We will have 3 HVAC units (2 and 3 ton down, 2 ton up with variable speed air handlers and 2 stage compressors). The installer is proposing to install one WHD (for entire house) on the larger of the downstairs unit which is also the unit that will control the kitchen and great room areas. The master bedroom/bath and another downstairs bedroom/bath will be on the other HVAC unit (no dehumidifier).

In Mechanicals | Asked By Richard Marks | Feb 14 17
1 Answer

Can anyone comment on the performance of the Rehau 4700 Geneo insulated uPVC window and door extrusions?

Can anyone comment on the performance of the Rehau 4700 Geneo insulated uPVC window and door extrusions that are manufactured by Wasco Windows in Wisconsin? They are apparently PassivHaus Certified. Are also triple glazed.

I am planning on building a Certified PassivHaus as well as Net Zero. Also want to use Quadblock ICF for the construction of the envelope.
Part of the design will have a full basement and two doors connecting to the garage. House is located in Ontario , Canada.
Any comments?
Thanks, Andy

In PassivHaus | Asked By Andreas Voura | Feb 15 17
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