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4 Answers

GSHP comparison calculator?

I'm looking for an online tool where I can plug in some basic figures such as EER and COP and compare cost/benefit of two ground source heat pumps. Any ideas? Thanks

In General questions | Asked By C. Maglio | Mar 28 15
0 Answers

New hybrid termite emerges in Florida

Read an article about scientists at the University of Florida discovering a new termite which is a hybrid species formed from the Asian termite and the Formosan subterranean termite. These two non-native species are now mating and have created a "super" termite which grows faster, eats more wood and can handle colder climates.

Not good news since termites already damage 600,000 homes per year in the US and we spend $5 BILLION on damage repair and treatments.

In Energy efficiency and durability | Asked By Peter L | Mar 29 15
2 Answers

How to insulate a condo concrete floor?

My daughter bought a condo in a highrise concrete structure. This past winter the floors have been cold even though the floor is the ceiling of a heated garage (55F) below. The shower floor next to an outer wall was 37F, outside temp was 12F. How can we insulate the shower and bathroom floor? The floor is ceramic tile.
We may even consider insulating the entire condo.

In Energy efficiency and durability | Asked By NORM DITTER | Mar 29 15
11 Answers

Insulating scissor truss

Hi, I am building my first house, what a project that has turned out to be but that's for another day. Anyways, our great room has scissor trusses for a nice pitched ceiling. I would like to have at least 24" of insulation to keep things nice and toasty in the winter. There is a 4' overhang outside on either end. I nailed a 24" high plywood leaving a vent space above where the red is on the layout. My question is what material and how to go about it. To use the high density cellulose is has to be contained by some mesh? Any input appreciated.

In Energy efficiency and durability | Asked By Tom Smith | Jul 19 14
3 Answers

JM Spider overhead

I was planning on using JM Spider on the underside of my structural roof deck. (There is a layer of peel and stick and 5.5" of polyiso foam board above the deck so no worries about vapor permeable insulation inside). The installer is having problems with getting the Spider to stick overhead. The installer says JM changed the fiber recently and they are having difficulties with some wall installations too. While they are working with JM, I was wondering:

Has anyone here had JM Spider installed overhead recently?

In General questions | Asked By Eric West | Mar 27 15
1 Answer

XPS as interior insulation on a plank wall

Architect's plan calls for 2" of "rigid" on interior side of a plank wall in Williamstown Ma (zone 5). Even if we tape the seams and air seal as best as possible, I am still concerned that moist air will get to the back of the planks and create moisture issues. The exterior is not being touched and I assume that there is no kind of air space between the planks and the siding. The space will be air conditioned in the summers and the 2" of xps (class II vapor retarder) gives me some drying capacity to the inside. Is that enough? How risky is the assembly?

In Energy efficiency and durability | Asked By Joseph Carry | Mar 27 15
8 Answers

Porch posts

We are building a wrap around porch that extends 6'. Since we know, because of code we have to use 6x6 for the posts for the deck, I have question about the posts that supper the roof.

One way is to use the same 6x6 and extend it from footer to header. We think that since these posts will be 6' apart going around the porch it might seem a bit too bulky.

Does code allow you to replace 6x6 posts with a PVC reinforced porch posts (they are turned and look like traditional porch posts)? Or do we have to stick with 6x6 lumber?

In Building Code Questions | Asked By Matt Cibula | Mar 25 15
9 Answers

Dryer vent in air-tight Passive House

I am building a house in the Seattle area to Passive House standards. After spending countless hours sealing every crack, seam and penetration to achieve under 0.6 ACH, creating a 4 inch diameter hole in my air barrier pains me. I've looked into condensing dryers that are used in some European Passive Houses, but they seam to take much longer to dry and use lots of water. Since I will be installing a vented dryer (unless someone can come up with another solution), are there ways to make the dryer wall vent more air-tight when the dryer is not in use?

In PassivHaus | Asked By Gerald Blycker | Nov 21 14
3 Answers

Manual J - Calcs - Mini Splits

Zone 4B - 3,300 sqft - 2 story - R10/R25/R60 with R8 windows - open floor plan design

The calcs came in at 3.25 tons heating/cooling. Two ductless minis per floor:
3 - 9,000 Btu Mitsubishi Hyper Heat Pumps - 26 SEER - 10.5 HSPF
1 - 12,000 Btu Mitsubishi Hyper Heat Pump - 26 SEER 10.5 HSPF

$12,000 installed (P&L) for all units - 10 year warranty

In Mechanicals | Asked By Peter L | Mar 26 15
7 Answers

Evaluating feasibility of solar panels in site rated at 895 (or 65% TSRF)

Just got a quote from solar panel install company and thinking I may skip solar and redirect funds to doing more insulation work on the house. But before I do that, I wanted to run some thoughts by here.

1. I am calculating that per kW I will be at $4.25 installed (I am in Boston area). Considering article I just saw today on GBA pegging average installed price $0.80 less per kW I am discouraged.

In Energy efficiency and durability | Asked By Apollo S | Mar 25 15
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