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4 Answers

ERV and humidity


I moved into a new house in Asheville, NC about a year ago. The house is very well sealed and has a Venmar Kubix ERV. In the summer, though, it tends to get really humid inside the house (anywhere from 55% to 75%). Is this normal in houses with ERVs? Is there an adjustment I can make on the ERV to fix this? I'm new to the ERV concept and need some help! Thanks in advance!


In General questions | Asked By Mickey Belcher | Jul 19 14
4 Answers

Spray foam

I have a weirdly designed house.

The attic in the lean-to addition has 2x6 joists (actual 2x6 - old wood). The joists sit directly on top of the wall framing for the ouside wall, and extend outward from there. They're notched to sit flat on the outside wall header. - there's less room for insulation there, as teh joists are no longer the full six inches.

There was never any room for both insulation and ventilation, so we have a 'hot roof'. It was created using three sheets of XPS foam sandwhiched together, and sealed with copious amounts of canned sprayfoam.

In Green building techniques | Asked By Anders Ufland | Jul 15 14
6 Answers

Are uPVC windows a good or bad idea at 7000' elevation and high solar insolation?

I am considering the purchase of Intus eForte windows for a new house. The windows would have be transported over several mountain passes up to 11,000 ft and then be installed at 7000 ft. This would require pressure relief valves that would vent the argon gas. Does this degrade the performance of the PH certifide window and would it become uncertifided?

In Energy efficiency and durability | Asked By Chuck Jensen | Jul 17 14
6 Answers

Building a durable deck

I'm looking at building a small free standing deck, perhaps 200 square feet or so. It'll be pretty low to the ground, less than 30 inches for sure. It seems to be widespread practice now to put rubber flashing on top of the beams, joists, and on joist ends, to protect the tops and hanger joint from water.

In Energy efficiency and durability | Asked By Nick Welch | Jul 17 14
4 Answers

Double stud wall -- mid-wall insulation = EPS or mineral wool?

I plan on a double stud wall with both walls framed 24" OC and aligned, and OSB sheathing on the outer face of the inner wall as the primary air barrier.

For essentially identical material cost I can use either mineral wool bats or EPS in the mid-wall cavity. The construction sequence would be slightly different as the EPS would be installed on the inside of the outer wall before the inner wall was erected while the mineral wool would be installed after the inner wall was up, through the openings in the outer wall.

In Energy efficiency and durability | Asked By Jerry Liebler | Jul 17 14
4 Answers

When installing an HRV for indoor air quality, is an independent duct system better than a "simple" installation?

I'm installing an HRV in my new house to improve air quality and mitigate outgassing of pressed wood cabinets, carpet, etc. (Climate zone 5a, so mixed humid conditions; hot summers, chilly winters but not too cold)

Initially, I was going to install a simple exhaust-only system with Panasonic bath fans, but then I came across a study that suggested that exhaust-only systems aren't as helpful for indoor air quality as an ERV (or an HRV):

Ventilation System Effectiveness and Tested Indoor Air Quality Impacts
Building America Report - 1309, March 2013
Armin Rudd and Daniel Bergey

In General questions | Asked By Patrick Cantwell | Jul 17 14
3 Answers

Exterior construction/insulation for a new home

I am about to start building a 3000 sqft, 1 1/2 story home in zone 3A W/H (central Alabama).
The house will have a standing seam metal roof and a drilled pier foundation with open crawl space. Air handlers and ductwork will be above the first floor ceiling, on the back side of the second floor knee wall.

My current construction/insulation plans are:
- Roof: Metal roof / Ice & water shield membrane/ 7/16 OSB/ Closed cell SPF sprayed 5" thick between 2 x 6 rafters

In General questions | Asked By Thierry Swinson | Jul 18 14
2 Answers

Insulation recommendations for a brick & block addition?

Hello GBA,

In Energy efficiency and durability | Asked By Brian Gray | Jul 18 14
8 Answers

Interior air sealing tape

Hello, I'm in the USA and currently constructing a two story addition. I have 14 windows and 2 doors already installed and I'm looking for the best way to air seal them on the interior. What interior air sealing tapes are available that would be used to air seal the rough opening gap on the windows? I've done a lot of searching and can't seem to find many options. Any help would be greatly appreciated. Thanks

In Energy efficiency and durability | Asked By SCOTT KOONS | Jul 16 14
11 Answers

Can a Trombe wall be used in reverse?

New construction, Panama City, Fl, 5,000-square-foot container (18) home facing south on piers. Will have 8' x 40' porch on west and east sides connecting to 8' x 80' porch on south side. Think U shape.

Due to high thermal conductivity of the metal, I was wondering if I could use a Trombe wall in reverse, pulling air from under home and venting it out at top of wall exteriorly. My thought is to remove convected heat transfer between the container walls so less insulation would be needed.

In Energy efficiency and durability | Asked By Les Amoss | Jul 16 14
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