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6 Answers

Cathedral ceiling fans and energy efficiency

Hi all,

I just moved in to a house with cathedral ceilings and a wood burning stove (insert) and trying to figure out how important a ceiling fan is. People say it will circulate heat down in the winter (if in reverse) but do folks have a sense of how substantial energy savings might be in gross ballpark percentage terms? Also, is it a benefit in the summer with central air and if so how much? Does the air movement get all the way down to cool in a meaningful way? Do you have to hang it low? Or can it be right at the top. I appreciate any wisdom any of you have to offer.


In Energy efficiency and durability | Asked By Roger Reynolds | Dec 8 14
10 Answers

I'm overthinking windows again... SHGC question

So I think we're close to choosing a local window producer to furnish our windows. Richlin 500 casements offer U values as low as 0.13, very good air seal numbers, are built down the road from us with a short lead time and an economy price. The only downfall that I'm aware of is that they insist on LoE272 glazing for their triple panes. This gives them a dismal 0.22 SHGC. Since I have 36SF of summer shaded, winter exposed, south facing window, I was thinking of going with a different window on the south side.

In PassivHaus | Asked By Ryan Griffin | Dec 4 14
3 Answers

Insulating a floor above a garage

So this is happening more and more in my office now where we are designing townhomes with a garage below the living space and now that we are building these units in a cold climate I am beginning to have greater issues with it due to the plumbing that needs to run through the floor cavity that is above the garage.

In Green building techniques | Asked By Joshua Lloyd | Dec 9 14
6 Answers

Rigid insulation on exterior walls with high interior humidity

I built an addition on my house that includes a solar thermal array on the roof that heats an endless pool in the addition. The existing house is brick, so when i poured the foundation (foam blocks), i included a 4" brickledge. i have not finished the exterior yet, and am rethinking my options. I am in zone 6b. The construction is 1/2" sheetrock over conventional (not staggered) 2x6 studs with faced fiberglass bats in the stud cavities. exterior sheathing is 7/16" osb. finally, tyvek house wrap.

In Green building techniques | Asked By norm rostocki | May 25 12
1 Answer

ERV or regular bath fan?

I am currently doing a 420sqft extension on the back of my house that includes a bathroom. All of the outside walls have been sealed on the inside with spray foamed at all of the seams, and the outside has been wrapped in Tyvek and 1/2 foam before vinyl siding. All of the drywall in the extension will be sealed with gaskets per ADA. The whole house including the extension is insulated with Roxul mineral wool. The original part of the house is not sealed per ADA, but is wrapped in Tyvek paper and .5 foam - I believe the seams are untaped. The house is heated and cooled with mini splits.

In Energy efficiency and durability | Asked By Kevin Schramm | Dec 8 14
1 Answer

New Home Build


I'm a long time reader. I've learned a great deal from reading these forums. We're building a new home real soon. Hopefully, we will be in this home a long time, and energy efficiency is important to me. I'm sure I'll have many more questions, but I'd appreciate any advice on the following to start.

Our home is 2,500 sf. It's basically a rectangular, two-story, shape. We are zone 4a.

In Energy efficiency and durability | Asked By C. Maglio | Dec 8 14
9 Answers

Ceiling air / vapor barrier... Is this a bad idea?

I'm still struggling with my ceiling air / vapor seal challenge. I'm adding R50 cellulose above my upstairs ceiling. I'm also trying to get the house air and vapor tight. In Minneapolis it's always either way too dry in winter or too humid in the summer.

In Green building techniques | Asked By Ryan Griffin | Dec 4 14
6 Answers

I can't find out how amps are converted to volts

As I said in an earlier thread I am making a solar powered usb charger. My solar panels have more than enough amps for the charge but the volts are behind at 7.71 and needs to be at 12. So my question is this: How are amps converted and how many amps WILL BE converted to supply the needed 4.3 volts more?
This is by far my favorite solar site.

In General questions | Asked By Shaye Miller | Dec 6 14
9 Answers

Noise from PEX/PVC drain pipes

We are at the stage of starting the framing for the new construction home in Pittsburgh. It is also a Passive House duplex. Our architect specified cast iron for domestic water drainage pipes (from shower and toilet, etc.), mostly on the account that these result in most quiet interior. For delivery of the water within the house, PEX is planned. Then we heard that iron pipes are more susceptible to clogging. Is some compromise, where pipes close to dining/living room are cast iron, and PEX elsewhere an OK option?

In General questions | Asked By Lucyna de Barbaro | Dec 6 14
7 Answers

Proper installation of 2 adjacent outdoor mini-split units?

We just finished a major renovation project that included sprayfoaming, all new windows, and one new Fujitsu Halcyon mini-split on each of the three levels. The temps are now dropping here in Maine, so we're finally getting a chance to experience the heating capabilities after a ton of research I did on this site and others (we do have backup electric heated floors and a propane fireplace ducted to the lower and upper levels as supplemental heat sources for brutally cold times).

In GBA Pro help | Asked By Phil Knutel | Dec 6 14
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