Community: Mechanicals

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!


4 Answers

Effects of 2" to 3" PVC dry drain pipes through crawl space

Good evening. I have a 2,600 SF home that has 900 SF crawl space under half of it. The builder placed all the overflow type drains (next to water heater/washer, next to my mechanicals, etc, to run to daylight into my far yard. These don't have water traps because they run to daylight I suppose and rarely if ever have drain water in them.

My house does not use A/C and in winter we currently use a large indoor wood burning stove and supplement cold rooms with electric oil radiant heaters, as-needed.

Asked By Andy Nels | Feb 11 16
7 Answers

GSHP and an endless pool

We have slowly been renovating our 115 year old, 2200 sq ft farm house over the past 12 years and live in northern Michigan (climate zone 6). This year we are replacing the 60 year old aluminum siding and roof and upgrading the walls to r30 and the roof to r60. We are also adding a 2425 gal endless pool/spa to the outdoor covered porch. I understand an outdoor pool in northern Michigan probably doesn't fall into the category of green building but it will definitely be fun!

Asked By Ryan Knight | Feb 9 16
3 Answers

Duct manifold for a stand-alone ERV

I'm trying to figure out the best way to install my ERV ductwork. I don't have a forced air system, so each supply or exhaust will have it's own duct. I have seen the typical trunk/branch method, but a manifold system seems easier. Does anyone have experience with building a manifold system for mechanical ventilation? I will have three exhaust ports and four fresh air ports. I've looked at the Zehnder systems and they look pretty slick, but I cannot afford the price. I am leaning toward Thermaflex ducts, which are high quality flexible ducts usually used in commercial applications. Thank you!

Asked By Adam Emter | Feb 9 16
5 Answers

Does anyone have experience with Zehnder ComfoFlex?

We are building a new house and in the final stages of design. The design includes an HRV and Zehnder ComfoTube looked great until I discovered that it is not UL listed. So, I'm curious if anyone can provide feedback on ComfoFlex. There isn't much on the intertubes...

Asked By Trevor Fontaine | Feb 9 16
7 Answers

Using a second water heater as an indirect fired tank?

I have two water heaters. A 50 gallon HTP Phoenix Light Duty propane water heater, and a 50 gallon electric resistance water heater. The two heaters are plumbed in series, electric water heater first, then propane. To make a long story short, some things didn't work out as originally planned, and now I'm paying an extra $15-20/month (and wasting source energy) because I'm heating up a bunch of water with electric resistance right next to a high efficiency propane water heater.

I'd like to stop doing that. I have a couple of extra constraints:

Asked By Tim C | Feb 8 16
7 Answers

Air exchange / ventilation / dehumidifier options for a sealed, 640 s.f. structure

I am building a 640 s.f. structure and insulating i twith closed cell spray foam. Heat is provided by a fireplace with an outside air supply and baseboard heat.

I need an energy-efficient air conditioning / ventilation / dehmidifier / air exchange solution, mainly to keep it dry, but also to keep it cool.

It is located in a typical, four season climate where we get hot, humid summers and cold, snowy winters.

Asked By Nathan Hiscock | Feb 8 16
5 Answers

Infrared panel heat: any reviews?

I am heating my zone 6 2300sf house with minisplits and a propane fireplace. The bathrooms, however are more isolated in the floor plan. I had been considering supplemental infloor electric radiant or kickspace heaters until I discovered ceiling- or wall-mounted infrared heating panels. The smallest 250w glass or steel units look like they easily heat 50sf rooms. Some are even available as a mirror. It looks like an efficient way to occasionally heat rooms that have air pulled into the HRV. Are there any good independent reviews out there on the concept?

Asked By Edward Mallett | Feb 8 16
16 Answers

Geothermal and SDHV in new ICF home

We are in the process of building a new home in Climate Zone 5. It is an ICF [insulated concrete form] construction from basement foundation to gable.

I am intending to use a SDHV [small duct, high velocity] system for forced air and heating in conjunction with a closed loop ground source heat pump.

What I am trying to understand is the impact to efficiency caused by my desire for SDHV on the heat pump options side of life.

Asked By Esteban Carlos | Feb 4 16
0 Answers

Proper DHP sizing

So, I ran a Manual J calculation for a number of Portland, OR apartment units I'm renovating (2bdrm/1ba, ~750sqft each). All fall in the 12.5k-13.5kbtu range for heat load; closer to 9-11.5k for cooling loads depending on orientation. When I click over to the Manual S sizing calculator, it mentions Emergency loads of 10k minimum - 18k maximum. I'm not sure what exactly this means, and how it should affect sizing choice. Calc outputs are attached for reference.

Asked By jonathan nagar | Feb 8 16
3 Answers

They didn't completely hook the cold air return on my furnace. Is that OK? What could happen?

can just using indoor instead of fresh outside air cause any problems?

Asked By Roger Blankenship II | Feb 1 16
Register for a free account and join the conversation


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