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25 Answers

Transoms and Ductless Minisplits


I am trying to heat and cool my second floor with one 12,000 btu ductless minisplit. I have heard that this is possible if I keep the bedroom doors open during the day to facilitate circulation of the hot or cool air.

However, does it get uncomfortable quickly in the night when the doors are closed. If so, I was thinking of putting in operable transoms over the doors. The only problem is they are kind of expensive (~$275 from Attached is my floor plan. I will be putting ceiling fans in each bedroom so maybe the transoms would be overkill?

Asked By Jimmy Nguyen | Mar 10 16
44 Answers

Inexpensive exterior insulation stand-off — Critiques?

I am trying to come up with some inexpensive, and sensible details to accommodate a 6" layer of exterior Roxul Comfortboard IS comprised of two layers of 3", 2' x 4' batts. See attached PDF for details. My concern is that with such a substantial thickness of Comfortboard, the potential for faster "sag" through this, or durability issues during seismic events is problematic. On many of our projects, we have screwed our vertical cedar 1x3 rain screen material directly through a single, thinner layer of the Comfortboard directly into the framing.

Asked By Burke Stoller | Apr 19 16
7 Answers

Moisture control dilemma: DIY walk-in cooler

I'm helping a great non-profit ( create an 8'X8' DIY walk-in cooler in an unconditioned warehouse. Plans include: 2x6 construction, R23 Roxul insul, wrapping the exterior of cube in Grace Ice and Water Shield, and a really nice, donated commercial refrigerator door. Interior is FRP (fiberglass reinforced panels) glued to 1/2" OSB. Temperature of 35-40 deg F will be managed with a 12K BTU window a/c controlled by a "CoolBot".


Asked By Karl Kaminski | Apr 26 16
1 Answer

Double walls, dense packing, and bendy sheathing

Many articles on double stud walls suggest fiberboard or gypsum as the exterior sheathing to prevent winter moisture issues. Given that thick walls require higher cellulose density, what tricks are there to keep the sheathing from bulging?


Zone 5, Rochester NY

Asked By John Ranson | Apr 25 16
5 Answers

Preparing for future solar panels

Building a new home and want to install solar panels at some point in the future. They won't be in the budget initially, when the house is built, but I want to prepare for them and make sure I don't miss something during the construction process that I will have to redo.

The panels will not go on the roof, they will go out in the yard or on an outbuilding or pergola, so I don't have to worry about running wires from the roof to the basement. However, do I need a particular type of breaker panel? Do I need to spec certain equipment?

Asked By Clay Whitenack | Apr 25 16
7 Answers

Is thermal bridging through a solid wood door a big deal?

We are going to be renovating our 1888 home to "pretty good" standards. I wasn't planning on doing anything to the original solid wood front door besides refinishing, squaring up and rehanging (but I'll pay attention to air sealing as much as possible - we are striving for <1.0 ACH). I am not so concerned about the energy losses caused by the thermal bridge but am a little concerned about creating a condition that causes the door to deteriorate (due to moisture or other reasons).

What, if anything, could happen to the door?

Asked By Alok Khuntia | Apr 20 16
15 Answers

Run furnace blower or HRV?

We are building a home is southeastern Michigan. It will have 3 110cfm bath fans (one in basement bathroom) and one 80 cfm bath fan (toilet room) and a 400 cfm hood range. I am concerned about air quality, as we a building a very tight house. Our HVAC contractor has said that he can simply program the furnace to run the blower every 1/2 hour to bring in more air which would be filtered. I believe he will also have a scuttle installed on the furnace. What are your thoughts? Most of the HVAC professionals I have talked to say that HRV systems don't work that well anyways. Thank you!

Asked By Carolyn Farrow | Apr 20 16
2 Answers

Okay to dry out cellulose wet for 10 days to use in an attic?

My insulation sprayed damp cellulose into the wall cavities, scooped up the waste, and put it in about a dozen plastic trash bags so I could dry it out and use it in my attic. (I know many installers put the waste back in the machine, but he was wary of doing so because of stray nails that could damage his machine, even though I had a clean job site.)

Asked By Michael Bluejay | Apr 21 16
7 Answers

Open-cell spray foam in historic retrofit

Hi, we are going to be renovating/adding to an 1888 Victorian to achieve "pretty good" near net-zero standards in the Chicago area. We are currently debating the type of spray foam to use in the existing structure (open cell vs closed cell). We will be using dense-packed cellulose with staggered stud walls in the addition.

Asked By Alok Khuntia | Apr 18 16
4 Answers

Economical way to insulate small attic

I have a small 8x12 entryway attached to the front of my house. The attic space above it is accessible from the second floor. I want to use it as conditioned storage space.

Asked By Brian C | Apr 12 16
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