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1 Answer

Interior vapor barrier

We had one room remodeled. One west wall (upstairs),one north and south wall now has outside insulation, fiberglass interior, poly sheet vapor barrier, and dry wall. Now I am wondering if we need to remove it. It is only in one bedroom, but I read your article and now I am concerned. Please give your thoughts. Thanks.

In General questions | Asked By Phette Place | Jul 29 16
11 Answers

ERV + dehumidifier ducting in a minisplit house

I'm working on a 2400sf house (CZ4, but very nearly 3) where the owners have selected minisplits - one ductless 1st floor, one ducted w/ very short runs for each of 2nd & 3rd. So there will be no major duct lines throughout the house for heatning and AC. They've also chosen to go the ERV and Dehumidifier route, this being the humid southeast.

In Mechanicals | Asked By Chris B | Jul 28 16
5 Answers

Separation of concrete slab and foundation

We removed carpeting in a condo that we own. We noticed by the sliding glass doors a crack in the slab. The slab has a layer of rigid insulation on the perimeter which seems to have seperated from the cinder block foundation. The cinder block wall does not appear to be bowing looking at it from the outside. Is this a big concern or is there a way to fix the problem without ripping everything up?

In General questions | Asked By Joel Silverman | Jul 29 16
4 Answers

Zone 6 Dew point

2"x6" wall
Roxul Comfort Batt R 23 in cavity
OSB Exterior
R-Tech 1/2" R 1.93 foil facer facing OSB, poly facer facing out, tape all seams
Owens Corning Fomular 150 2" R 10

In your opinion is this an acceptable wall structure for Zone 6, or do you need to add an interior or exterior vapor retarder. The R-Tech product has a water vapor transmission <1 (perms) and Absorption <1 (% vol)

In General questions | Asked By David Dunn | Jul 29 16
14 Answers

Open-cell foam contacting a water heater flue

I have open cell foam being put into my attic. My hot water heater is in the garage below, but where the flue goes through the rafters, is it OK for the open cell foam to contact around the flue? If not, how much of a gap is left around it? I guess they would have to just cut that gap after foaming since the foam isnt going to just cooperate....

In General questions | Asked By John Sexton | Jul 27 16
3 Answers

ERV as a bathroom vent fan?

My wife and I are purchasing a new house. House is in NJ and was built in 1987. Stick framing, average to slightly above average construction quality, average energy efficiency as far as we can tell.

For whatever reason, none of the bathrooms have vent fans. Putting fans in is likely to be one of the first projects I do.

Simple question - is an ERV appropriate to use as bathroom ventilation in a not-so-tight house? Our priorities are as follows:

#1 remove moisture to reduce mirror steaming and mold potential
#2 energy efficiency in terms of not wasting heated/cooled air

In Mechanicals | Asked By Matt Culik | Jul 28 16
5 Answers

Reducing humidity without AC

I live in NJ. Typical summer weather here is highs in the mid-80s/low-90s, lows in the 70s, and very humid.

Our house has a "natural" overnight temperature of about 73. What I mean by this is that if I set the AC to 74 before we go to bed, it cycles on/off until about 3AM, at which point everything has cooled off enough outside that no more AC is required to hold 74.

While this is nice from an electricity use perspective, no AC means the interior air gets stuffy and the humidity starts to creep up.

What is the most energy efficient way to address this?

In Mechanicals | Asked By Matt Culik | Jul 28 16
8 Answers

Blown-in insulation for existing walls

My circa 1900 house in West Virginia (Zone 5) has hardwood paneling throughout the interior and wood siding on the exterior with no insulation in-between the actual 2x4 walls. I'm pondering either blow-in cellulose or open cell spray polyurethane foam applied through holes in the siding. (Should I consider other options?) Both open-cell SPF and cellulose show an R-value of 3.2 to 3.8/inch. I understand the cellulose will settle over time leaving some gap at the top and foam will not. I like the idea of an air barrier provided by SPF between the leaky wood interior and exterior surfaces.

In Green products and materials | Asked By Andy Kerr | Jul 25 16
3 Answers

Aeroseal duct sealant

Hello. My heating and air tech recommended aeroseal to repair leaking duct-work in our walls. We are going to replace duct-work in our attic but looking to this product so we don't have to tear out walls. Does anyone have any experience with this product? It says that is is low voc and a non-volatile vinyl acetate. I realize that sealing small holes is good for using less electricity and producing less dust which in turn produces better air quality but if aeroseal off gasses and eventually degrades overtime then am I just breathing in a different type of pollutant?

In Green products and materials | Asked By Lori Wilson | Jul 27 16
10 Answers

Choose Slightly Higher HSPF or save $ upfront as payoff is ~7 years.

I'm looking to buy a mini-split for my business office. Seems simple enough but I have 3 basic choices.
15 SEER 9 HSPF at base price for either 115v/230v, simple inverter
21.5 SEER 9.8 HSPF(IV) bp+$300 for 230v, upgraded inverter
21.5 SEER 11.2 HSPF(IV) bp+$320 for 115v, upgraded inverter
I've no problem installing 230v vs 115v and it's only 5' from the panel.

First, is it even worth paying the $300+ for about a $40/year savings? 9 vs 9.8 or 11.2,

In GBA Pro help | Asked By Karl Koning | Jul 27 16
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