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

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

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

If you want to post a question, 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!

13 Answers

Difficulty finding a modulating multi-zone air-source heat pump

I need to finalize the equipment selection for my current build. My engineer along with Mitsubishi spec'd a City Multi (VRF) PUMY outdoor unit with multiple indoor units. Unfortunately, this outdoor unit does not have hyper-heat, which means that in order to meet the 99% heating requirements, it will be grossly oversized for cooling. While the compressor can operate down to low-20% of rated capacity, that is still much higher than an MXZ minimum operation for the same sized unit.

Asked By Jonathan Lawrence CZ 4A New Jersey | May 21 18
1 Answer

Egress Question


This is a dumb egress question. If a small 12'x16' cabin was built (one room + one bathroom), would any of the windows need to meet egress? There will be an exterior door obviously. If there are no walls inside, would the exterior door count as a means of egress?


Asked By John Brown | May 25 18
8 Answers

Insulating Wall Between two Different Slab Elevations

I have a basement with 2 different slab elevations with 2' differential between the two. There will be a stair with 3 risers connecting them. I am insulating the basement from the inside. We are getting ready to pour the slab next week and in preparation I have placed 4" of EPS on top of the sub-slab stone. I am trying to decide how to best insulate the concrete wall between the 2 elevations where the stair will be.

Asked By Jonathan Lawrence CZ 4A New Jersey | May 24 18
4 Answers

Purchasing/DIY single mini-split

We have a poorly insulated, 260sqft finished bonus room above our garage. I just removed a 23yo TWO TON AC unit (!). There is baseboard electric heating.

What is the best way to purchase a single minisplit for this space and hire an hourly HVAC installer (eg, someone moonlighting by the hour)?

Asked By Emerson | May 25 18
8 Answers

Should I insulate and/or heat my unfinished basement?

I have a 100 year old house in Georgia with an unfinished basement. We have no intentions of finishing the basement but we do want to use it for storage and a place for our dogs to sleep when we are at work. The floor is a concrete slab with a vapor barrier under the slab. The foundation walls are mostly above grade and are a mix of brick piers with brick and cmu infill. There are currently no water issues. The walls have several foundation vents that we close in winter.

Asked By J Greene | May 24 18
6 Answers

1 1/2 story farmhouse in British Columbia

Hi, I'm looking for some thoughts on our current design for our 2000 sqft home.

Asked By Michael Blake | May 22 18
1 Answer

How do we hire a green building advisor on an hourly basis?

Does greenbuildingadvisor maintain a directory of recommended consultants?

Asked By Joe Martin | May 24 18
4 Answers

Vaulted / Cathedral Ceiling -- Unvented

Hi, I'm in the process of building a cabin near Saskatoon, Saskatchewan, Canada. I can't tell for sure since the climate zone map is for the US only, but I'm guessing this would be equivalent to Zone 6B or 7B.

Asked By User-7075735 | May 23 18
3 Answers

Ducted/concealed mini-split without supply or return plenums - straight out the wall?

I'm planning to install a "ducted"/concealed Daikin LV unit on the second story of my house. I haven't been able to find any definitive answers on plenum requirements, or lack there of.

the plan includes hanging the unit from unistrut in the hallway, observing all of the required tolerances for access and space around the unit. A sofit will then be built around the unit.

Asked By neockder | May 23 18
7 Answers

Ecodrain Drain Water Heat Recovery

I first learned about Drain Water Heat Recovery pipes here on GBA and wanted to give back a very small token of appreciation in a short review.

I recently ordered and installed Ecodrain's V1000 and have been quite impressed with it. It's near the top of the CSA B55.1 list for highest efficiency and the price is quite reasonable:
3-inch diameter models:

VT1000-3-36 .......... $469
VT1000-3-48 .......... $524--my model
VT1000-3-60 .......... $564
VT1000-3-72 .......... $614

4-inch diameter models:

VT1000-4-36 .......... $549
VT1000-4-48 .......... $644

Asked By pat beurskens | May 22 18
Register for a free account and join the conversation

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