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4 Answers

High-efficiency furnace modes

This might not be the best forum for this question but here it goes…..I just got a high efficiency dual stage furnace installed (LENNOX EL296E Series Dual-Stage 96% Efficient Gas Furnace). I don’t think the blower is variable but comes with a consistent torque motor. It also came with a Nest thermostat. My questions is how does the system know what stage the furnace should run in and what speed the blower should be at? Does the furnace make this determination or is the Nest thermostat telling it what mode to operate in?

In General questions | Asked By Bryan56 | Jul 19 17
3 Answers

1926 Tudor basement finishing project


Our house is a 1926 Tudor located in Minneapolis. I am in the process of finishing the basement. Planned insulation is 2" rigid (polyiso or XPS) with 2x4 stud wall. I am only air sealing the rim joist due to the fact my floor joist are half buried in concrete.

In Green building techniques | Asked By Joe Sweeney | Jul 18 17
6 Answers

Two minisplits in one room

I just had my mini split system installed. I got multiple opinions from the installation contractor regarding the number of indoor units in one room. There is the setup:

In Energy efficiency and durability | Asked By Bryan56 | Jun 27 17
32 Answers

Minisplit sizing and number of minisplit heads for this apartment?

Hello Martin and Dana,

We continue to progress on our project and are about to have the rough electrical started. As a refresher, this is the 700 sq. ft. apartment inside a post-frame construction shop building in climate zone 3.( My last dilemma I needed help with was a question about insulation between studs along with exterior insulation)

I am talking with an HVAC contractor who specializes in Mitsubishi products. I realize you get 20 questions per week exactly like what I am about to ask, and I appreciate the patient help.

In GBA Pro help | Asked By John Peeper | Jul 13 17
19 Answers

Need ventilation suggestions for remodeled office - it's too tight!

Hi all -

I've successfully converted my residential 20x20 garage into a beautiful office and photo/video studio. It's beautiful and I'm very happy except for one thing: lot's of off-gassing, VOCs, and chemical smell. I've had the windows open for most of the last year and still if I close them, the odors build up over a few hours. Air testing shows high levels of VOCs, and detectable formaldehyde - likely from the spray foam or polyspartic floor covering but hard to say.

In General questions | Asked By Dave H | Jul 17 17
7 Answers

Mini split options under $1500?

I'm building a small guest which is ~450 square feet. I want to put a mini split in there but do not want to spend $3000 plus.

I see Pioneer brand mini splits on Amazon for around $700. I realize these probably aren't the quality of the more expensive units HVAC companies sell you but has anyone installed one of these before? They have amazing reviews online.

Alternatively, can anyone recommend another unit that I could get for under $1500 (including installation cost from professional)?


In Energy efficiency and durability | Asked By Rocky12 | Jul 17 17
2 Answers

6" wide aluminum insect screen

Anybody have a good resource with fast shipping? I'm looking at having to cut it into 6" strips from a 24" wide roll unless someone saves me!

In Green products and materials | Asked By Inger Peters | Jul 19 17
6 Answers

Best insulation and sealing for a tucked-under-garage ceiling?

We are purchasing a circa 1966 Cape in the Philadelphia are with the garage tucked under the master and guest bedrooms and two baths. The garage ceiling is currently covered with Homasote, but there are small areas where we can see an underlying plaster ceiling with missing chunks. The joists are 2x10s and there appears to be some fiberglass insulation batts in place.The HVAC ducts run below the joists and are mostly covered in Homasote, but several feet of ducts near the overhead door opening are exposed and uninsulated, but with remnants of asbestos.

In GBA Pro help | Asked By Geoffrey Simon | Jul 17 17
3 Answers


I thought I had a GC/Framer lined up to build a 16" double stud wall but they have backed off. I found a builder willing to get <3ACH, code in NYS is 3 ACH@50, but not double stud, only 2x6 and he wants to use spray foam. Being PHPP only list kBTU/(ft²yr), how do we convert that to MAX BTU/Hr?

Is this the correct conversion for average BTU/Hr?

([PHPP kBTU/(ft²yr)] * 1000 * [square ft]) / 365 days / 24 Hr = average BTU/Hr

In PassivHaus | Asked By Jeff Ziegler | Jul 19 17
3 Answers

Specifying or noting "Mooney" x-hatching on ext. walls

The contractor who is building the dried-in shell for my house gave me the green light to add the "Mooney"-like cross-hatching to the exterior walls. The building department wants to see the x-hatch on the plans that I submit.
I'm showing the ext. walls 1½" thicker but I don't know the right ways to note the x-hatching.
Could someone attach a couple examples or describe the appropriate note?
Does someone have a detail drawing they have used before?

In Plans Review | Asked By Mark Walker | Jul 18 17
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