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2 Answers

Best practices for HRV on a budget

I am building a simple but efficient home in climate zone C4. It will be a 3 bedroom, 2000 sq ft home. with us living mostly in the upper half. I was originally planning on putting one or two panasonic spot ERVs in but am know thinking it might be better for overall air quality, efficiency, and spreading the heat from my two headed mini-split, to put a fully ducted HRV unit in. I have been looking at the Fantec FLEX100H, and the Lifebreath RNC 95. Money is a huge issue but the price difference between two panasonics and one of these units is not much.

In Energy efficiency and durability | Asked By Kail Zuschlag | Nov 29 15
2 Answers

Adding foam board to ceiling rafters?


The rafters in my ceiling are only 2 x 6. Is it acceptable to lay polyiso sheets across the top of the rafters, or should I be concerned about the foam acting as a second vapor barrier? The fiberglass batts have a kraft liner facing the sheet rock.

If the answer to the above is yes, can I place the foam in between the rafters against the sheet rock under the fiberglass batts?


In Green building techniques | Asked By Donald Mendell | Nov 29 15
1 Answer

Recommendations for a small HRV

Hi everyone
I'm looking to buy an HRV for our small (1000 sqft) ranch home.

I already installed all the dedicated ductwork last year and had been using a home-made HRV that worked very well, but I don't have the time to keep tinkering with it to get it to work just right. The cabinet was made of plywood and I kept having problems with the air streams crossing and causing condensation and mold in the cabinet.
Anyway as a result I'm going to hook up a new HRV to my ductwork.

I'd like a small unit - I will be installing it in a closet
Quiet would be good
Also with ports on top

In Mechanicals | Asked By Carlo Giombi | Oct 12 15
0 Answers

Questions about insulating 1947 concrete block home in Florida

We purchased a house in Orlando that we plan using as a rental. It is a one story block home, about 850 square feet. As with most houses built here during that time period it had no insulation with the exception of some blown in cellulose in the attic. We have gutted the house and found that originally there was no furring strips and drywall on the inside of the exterior walls, they have been painted and wall papered a couple of times then someone furred them out and put up wood paneling.

In General questions | Asked By Nathan Vaughn | Nov 29 15
0 Answers

Source for Rock Wool batts in Albany NY area

I am interested in using Roxul or other rock wool peoduct in bith batt form and board form for my build in Saratoga County NY, near Albany. Is there anyone here that can recommend either or both a source and an installer in this area?

In Green products and materials | Asked By Joe Suhrada | Nov 29 15
1 Answer

Where to put Smart Vapor Retarder?

We are remodeling the second floor of our 1956 Cape in Williamsburg VA, climate zone 4. I need advice about where to incorporate the MemBrain smart vapor retarder in the roof and wall insulation stack up.

Roof stackup: Asphalt shingles- Durabuild synthetic underlayment-1x8 plank roof decking- approximately 1.5 inch airspace (ProVent running soffit to ridge vet)- 3.5 inches of Roxul R15 between the 2x6 rafters- 5.5 inches of Roxul R23 between 2x6 “mooney wall” furring running perpendicular to the rafters- sheetrock.

In Energy efficiency and durability | Asked By Chris Kolloff | Nov 29 15
2 Answers

To vent or not to vent?

First, I apologize for a question asked many times on here. After just asking about access to an unvented attic, I started to question the whole unvented idea. I live in zone 3, plan to use Zip R (R-6.6) with cellulose inside 2x6 walls.

I originally planned on unvented with 5 inch nailbase with around 3 inches of OC spray foam in the bottom of roof.

I've read every article I can find on the subject on here and other sites. If my ducts and air handler will not be in the attic, would it be better to go unvented? I know with unvented you gain a lot of volume of air to condition.

In General questions | Asked By Eric | Nov 28 15
0 Answers

detail on garage wall abutment to exterior block wall

Hi there - been using this site for about a year. Just performed an energy retrofit where I ripped out the ceiling in the garage Redid the ducting system, fixed a lot of electrical that was wired incorrectly or unsafe, airsealed, put ithen put in two layers of 1/2" polyisocyanurate, covered with 1/2" drywall.

If you follow this link: http://www.greenbuildingadvisor.com/cad/detail/air-barrier-garage-band-j...

that is exactly the configuration i built to (I did not use furring strips like the detail calls out though).

In Green building techniques | Asked By daniel slaman | Nov 29 15
2 Answers

Locating manifold of a radiant floor heating system

Recently acquired a Condo that has propane fired radiant floor heating system. The house inspection showed it to be working. Recently as the cold weather begins in earnest the system cannot keep up... had a local reputable company diagnose the problem which they determined is caused by air in the system. They were able to remove some of the air at the boiler. As they drained water from the system it was very brown. In any case, the heating improved in some of the rooms as measured at the floor with an infrared thermometer. But not all. The thermostat was replaced with a programable model.

In Mechanicals | Asked By Carroll Ayer | Nov 28 15
14 Answers

Can PEX pipe be reused after a fitting is removed?

I've had 3 plastic on brass pex swivel connections fail. Each time I noticed water, reached up to check the connections only to have the nuts shatter in my hand. The first two times I used push connect fittings to replace the swivel fittings, connecting to the supply after the fitting was attached to the sink. After another failure yesterday on Thanksgiving I've decided to replace all the plastic on brass with all brass swivel fittings. I hack-sawed the pillow-top of the crimp connection then used a hair dryer to heat the pex, pulled out the brass shank and slid off the clamp.

In GBA Pro help | Asked By K C | Nov 27 15
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