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6 Answers

Passivhaus total energy usage standard

One of the Passivhaus standards is that total energy usage including appliances cannot exceed 11.1 kwh per sq. ft. per year. If I have a 2800 square foot house, then if my total kwh usage is under 31,080 (11.1 x 2800) that is pretty good right?

Seems like that's a pretty low bar. Or am I misinterpreting?


In PassivHaus | Asked By Jimmy Nguyen | May 11 17
17 Answers

Georgia Power's PV policy

We are under Georgia Power which does not allow net metering. Instead, I think we currently get reimbursed 4.2 cents/kwh for what our PV system produces, which is about 1/3 of what GA Power charges us for their power. Complicating matters is that during the summer, when our west-facing array is producing significant output, we are on GA Power's "Nights & Weekends" program which charges 20 cents/kwh on afternoons and 5 cents/kwh at all other times.

In Mechanicals | Asked By charles CAMPBELL | May 12 17
10 Answers

Deep blown in cellulose for attic - questions

I have a few questions regarding deep (beyond R60) blown in cellulose for an attic. Cellulose is relatively cheap and I'd like to maximise my attic insulation without causing any other issues:

1. Several manufacturers of cellulose insulation have depth/R-value charts that stop at R60. Is there any practical reason for this, or is it just because most people don't bother going above R60?

2. Does compression above a certain depth negatively affect the performance of the insulation in any way? I.E. does your R-value/$ go down appreciably beyond a certain depth?

In Energy efficiency and durability | Asked By Lance Peters | Apr 24 17
15 Answers

Final design: Roof, walls, and floor

So getting final details of a new build in Zone 6 (Osaca, ON) Hopefully pretty good house , that will be Net-Zero.
Any comments or suggestions before I finalize this? Thanks !!!

Roof setup:
Standing seam metal roof
Blueskin self-adhered membrane
5/8 plywood
2” air gap
attic truss with raised heal
24” minimum blown in cellulose
1/2” drywall
latex paint

Wall setup Outside to Inside:
Vinyl Board and Batten Siding
1x4 furring strips mounted horizontal 12” OC
2 layers of 2” Silverboard EPS taped seams
Blueskin VP100 ,maybe something else?

In Green building techniques | Asked By Dave B | Apr 4 17
54 Answers

Another crawl space in the Northwest

Hello all, I have a 1150 sq ft rambler house in Fall City, Washington (near Seattle), zone marine 4c. I am currently in the process of redoing the crawl space. I have pulled the damaged and rodent infested insulation down, and removed the town vapor barrier. It seems I had some rodents that were digging past the foundation and getting into the crawlspace, ruining everything.

In Energy efficiency and durability | Asked By David Meyer | Nov 28 16
10 Answers

Foundation waterproofing retrofit

Howdy. I know questions come up like this all the time but I've been reading a thousand pages on the subject and would appreciate some sanity-checking on my plan.

We bought a house last year that's roughly two years old. I'm no expert, but I think it would be considered a mid-level build; it certainly isn't a green/leed-level design.

We have a poured concrete foundation with a crawlspace. Heavy clay backfill. I've noticed some water intrusion into the crawlspace around some of the pipe penetrations; not a ton of water, but some.

In General questions | Asked By Maurice A | May 13 17
2 Answers

Rheem heat pump water heater ducting

I'm in climate zone 4C, 22°F design temp, 4500 HDD, high radon potential (conditioned crawl not allowed). My heating season is basically mid-Nov through end of April. Cooling from mid-June to mid-September.
Energy Star is rewarding the use of an HPWH and the local utility is offering a $500 rebate for such (free money).
Does it make more sense to
1) Install the WH in the garage, which gives up the cooling in the summer and the COP in the winter (it will use more resistance heat in the winter);
2) Duct it to the attic or crawl space all the time;

In Energy efficiency and durability | Asked By Mark Walker | May 13 17
8 Answers

Would a rainscreen be required?


I would like to install 1.5" of mineral wool on the exterior before finishing with vinyl. I am pretty sure vinyl siding can be installed on foam insulation up to 2" without a rainscreen suggested but the mineral wool is less dense and I worry it wont hold the vinyl the same.
Are there any best practices when installing vinyl over mineral wool?
Thanks in advance

In General questions | Asked By Jeremy Archer | May 3 17
18 Answers

Is a single head minisplit practical?

This is a mostly accurate plan of dear, old Mom's house.
2265 ft²; zone 4 marine; target ACH50 = 1.5; 5000 HDD; 22°F design temp;
2x6 walls w/2 stud corners, 24" o.c., 1½" horizontal cross-hatched walls (similar to "Mooney"), 7" of dense pack cellulose; front wall faces north; awesome PV potential on south facing roof.

In Mechanicals | Asked By Mark Walker | Apr 27 17
2 Answers

Furnace cold air return requirement with HRV

New build in Ontario with Zehnder ComfoAir 550 HRV (home run system - not tied into furnace)

Does the furnace need traditional cold air returns in various rooms or can we just draw air back into the furnace directly from the basement (where the furnace is located)

The HRV is already moving air so not sure of the purpose of the cold air returns in this setup


In Building Code Questions | Asked By Steve Babcock | May 12 17
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