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!


1 Answer

Mitsubishi hyperheat multi-splits and modulation

I'm thinking about having an MXZ-4C36NAHZ installed. The indoor units would be one (1) MVZ-A18AA7 ducted air handler and and two (2) MSZ-FH09NA wall units.

The 4C36NAHZ submittals say it can modulate down to 6,000 btu cooling and 7,200 btu heating.

I cannot find the minimum operating capacity of the MVZ-A18AA7, but the similar PVA-A18AA7 can modulate down to 7,000 btu cooling. The MSZ-FH09NA units can modulate down to 1,600 btu cooling.

Asked By Aun Safe | May 25 18
0 Answers

Best Value Mini-Split for Cooling, Some Heating?

Climate Zone 6A, Toronto Ontario

I was at my Mom's place over the weekend and we were discussing windows and air conditioners for her small house. Her house is a small 1970's backsplit layout, about 1500 sqft including the rear basement living area, all 2x4 construction. Right now all she has is a window mounted air conditioner that she places in the master bedroom which is on the upper level a the rear of the house. It does a poor job of cooling the house but does give her relief at night for sleeping.

Asked By Lance Peters | May 26 18
9 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
0 Answers

High-R Wall Design in a Wildfire Zone?

I am in the process of designing a high-R wall for my future home build in Nederland, Colorado. The property is located at 8600 ft. in climate zone 6/7 and in a high wildfire danger zone. My priorities are a tight building envelope with high-R walls and more environmentally friendly materials that also resist fire, but I'm also trying to get the most bang for the buck on those materials. I’ve read various articles on this site and others, and they’ve been very helpful, but I’d love some input on my design. Here’s what I’ve come up with:

Asked By Will Welch | May 25 18
5 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
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

Hello,

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?

Thanks.

Asked By John Brown | 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
Register for a free account and join the conversation


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