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15 Answers

Geothermal vs. air-source heat pump

I have researching and getting quotes on hvac for a while now.. It is getting to crunch time.
Well insulated, tight house.

All three quotes include:
3 units, 3 air handlers, each zoned 3 times. Rigid Trunks and short flex runs.

option A. Carrier 18seer 25vna08... 5 stage. ( I don't like the potential harmonics problems of their greenspeed)

option B. Lennox x25 top of their line variable.

option c. Waterfurnace 7 series geothermal units. horizontally drilled ground loop.

Asked By Dean Sandbo | Jun 22 16
8 Answers

Making the best of a misplaced vapor barrier

The project: an aluminum-bodied step van to be converted to a low-energy tinyhouse. It will move around once in a while, and needs to handle a range of climates.

The materials:
- heavy aluminum skin, built fairly air-tight (much tighter than corrugated RV siding)
- 4" thick fiber/paper-faced polyiso
- plywood interior panels, most likely
- a 100W heater/vapor generator that runs on potatoes and wine
- additionally heated by a woodstove when it's feasible, catalytic propane when it's not. I'm also looking into air-air heat exchangers.

Asked By Geva edhrven | Jun 13 16
16 Answers

R-values of ceiling and walls

Zone 5a (on the border of zone 4)
Existing uninsulated concrete slab.
No basement. 2x4 frame.
A bunch of newbie questions.

http://www.homepower.com/insulation-zones
Why is the insulation recommendation for an attic so much higher than for an cathedral ceiling?
Both are the shell of the building but the attic has an ceiling under it that at least adds some insulation value. I would expect the recommendations to be closer or even reversed.

Many sites stress the importance of a high R-value to save energy.

Asked By Tony Tibbar | Jun 3 16
3 Answers

Unvented cathedral ceiling — insulating from above

I am re-doing my family room roof, which is a cathedral ceiling.

Since the roof is being re-shingled, I thought it a good time to remove the sheathing and lay down some closed cell foam. I have some unopened from a previous project

Everything I've read about unvented Cathedral ceilings talk about them drying from the inside. Obviously this can't happen if I'm spray in the closed cell foam onto the dry wall ceiling from above

The ceiling is 8" from drywall to plywood

Asked By Paul Buchkowski | Jun 25 16
1 Answer

Is there a way to install the vents for an attic fan, even though we have siding on the house?

Two years ago my parents had their house sided. The house had an attic fan with all the proper vents .they always use the the fa as you described it. It's great. However and this is a biggie, the siding company closed in the ventilation for the fan. They tried to contact the siding company, but the seemed to drop off the planet. Is there anything that can be done to use the fan again?????? Please help!!! Thank you.

Asked By Gretchen Obst | Jun 25 16
9 Answers

Room on second floor of house that cannot be cooled with AC.

We have a 40 year old house with a 7 year old central air unit. The duct work makes it difficult for the AC to keep the upstairs as cool as desired on extremely warm days (92+). We have dual zone thermostats so we just use the upstairs unit for AC, which helps. We recently replaced the windows and have insulated the attic, so overall the system is adequate. We do, however, have one room that consistently runs 8-10 degrees warmer than the rest of the second floor. Cool air is coming through the register.

Asked By Tim Duffy | Jun 25 16
9 Answers

Insulation options?

Zone 3 remodel (gutted)

Please help decide how to finish off the insulation on the inside.

from the outside
zip r6 sheathing
1" xps
block wall

essentially r11 on the outside of the block.

I have started to put 1" xps on the interior of the block wall and 1" furring strips... I am realizing that this is taking up 2" of space... and I have the ability instead (and probably a lot easier) to just frame a 2x4 wall on the inside instead.

I am spray foaming the roof deck with 8" of open cell.

Asked By Dean Sandbo | Jun 22 16
2 Answers

Crawl space drainage

The best I can tell there is a spring (seep) under my house.

This is not an uncommon is our area. Most everybody has a spring or seep in their yard or around the foundation or both.

Asked By Eric Dolly | Jun 23 16
11 Answers

Sizing a whole-house fan for a larger house?

Hi All,

Considering a whole house fan for our soon-to-be-built "Pretty Good House" in Central KY, zone 4A.

The house is on the larger size, and the calculations for the type of WHF I need are off the charts in terms of what is available in the marketplace (I assume), what I have attic venting for, etc.

So, keeping in mind that the fans in the marketplace are about, say, one third or one half the size it needs to be sized correctly, is there still a benefit to including one in our build?

Asked By Clay Whitenack | Jun 21 16
2 Answers

Vapor barrier yes/no?

I am looking to insulate a new, unvented,sealed, cathedral ceiling assembly on 2 x 10 joists. I plan on shooting 3 inches of closed cell urethane foam (r18 to r20 value) directly under the plywood or aspenite roof deck, after which, I will fill the balance of the rafters with 6 inches of Roxul batt (r22 value). I will also apply ice and water shield atop the plywood roof deck, then strap it, then lay down my metal roofing. My question is, do I need to apply or should I need to apply, a vapor barrier underneath the batt before installing my ceiling gypse?

Asked By Jean Blain | Jun 22 16
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