Community: Energy efficiency and durability

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17 Answers

Hi. I am back and forth on whether I should use XPS (blue board) or EPS for the insulation underneath my slab. I understand the qualities of each regarding water absorption and drying out, but would it (XPS particularly) affect the long term performance to the point where the slab is compromised? I also understand the pollution associated with XPS manufacturing. I have the option of purchasing 6" (house in very cold climate) of EPS (R-24) or 4" of XPS (R-20). The EPS is less expensive per inch, however, I need to pay for shipping which jacks up the price.

Asked By Matthew Michaud | May 2 14
2 Answers

Most of the blower door tests that are mentioned on GBA give numbers under 3 or 2 or 1 ACH50. I'm guessing that none of these homes have a traditional fireplace. How much does a traditional fireplace with standard chimney damper contribute to air exchange numbers? What are some recommendations for improving a house with fireplace and chimney?

Asked By Derek Roff | Sep 1 14
4 Answers

Hi,
I am currently redoing the exterior of my house with a new vinyl siding and changing all windows. My house was built in the mid 80's and have 2x6 studs with Batt Insulation and mostly without a vapor barrier... but the insulation is not great, especially the air goes through the house.
My question is what is the best insulation for me to put outside the house underneath the vinyl siding. My windows will allow me to go up to 1 inches of exterior insulation.
So XPS with Typar? Polyisocyanurate (IKO Ener Air )? Others?

Asked By Jason Haché | Aug 29 14
4 Answers

I am replacing my existing siding and I am doing the following -stud - 5/8" plywood - 1-1/2" of Polyisol, 3/8" rain screen, WRB, fiber cement siding. The house is in the San Francisco bay area on a hill with a stepped foundation.

Asked By Randy Mason | Aug 30 14
1 Answer

I live in the San Francisco bay area and am going to use 1-1/2" rigid foam board and a rain screen on the exterior of my house. I have read numerous articles in regards to using insect screen at the tops and bottoms of the rainscreen wall, however no specific details about the type of insect screen is ever mentioned.

There are numerous types of insect screens (Aluminum, Fiberglass Bronze, galvanized, etc.) available.

Asked By Randy Mason | Aug 30 14
5 Answers

I am in zone 5A and I have a problem of excess humidity in my ICF home with no abnormal sources of moisture (5 occupants of a 2150 sft home with a full basement). This results in condensation on the wall of windows facing a pond on the north.

Since a dehumidifier will also dump heat into the home helping my all-electric furnace heat the home, I am wondering if it would cheaper to run the dehumidifier than to use an ERV to lessen the humidity in the home. I realize in the latter case, there's some loss of sensible heat that the electric furnace would then have to compensate for.

TIA.

Asked By Venkat Y | Aug 29 14
1 Answer

So based on everything thing I am reading should we be using R3 R4 or R5 for each inch of Polyiso since it decreases in performance as it gets colder. I seem to be seeing some variation in Answers. I am in zone 5 and was planning on putting 5 inches of Polyiso.(thinking that was R 30 Roughly but if is is only R 15 when coldest that is a problem) Now it seems like I would be better served with three inches of polyiso with EPS on top. I have access to 1.5 or 2.75 inch EPS. Would I still be OK with 3 inches of polyiso and 2.75 inch of EPS on top?

Asked By terry grube | Aug 29 14
Answers

Hi Folks,

I am advising on a home renovation in Sudbury, MA. It has become obvious that the structure -- about 20 years old -- was built without thought to airsealing. The resulting home performance problems are likely predictable to GBA readers.

Now, the owners are turning a 3-season sun room into a 4-season room and need help figuring out how to best heat and cool the new space. This project also presents an opportunity to address other related issues.

Asked By c talwalkar | Aug 30 14
3 Answers

My new house is designed to limit penetrations through the building envelope to as few as possible. Nevertheless, sillcocks, outside electrical receptacles, outside lights, HRV intake/ exhaust, etc. need to be sealed.
Are there methods or products that are more effective than others? How about ease of installation? I've seen photos of tape covering holes and that seems like a pretty clunky solution. I'm probably going to either do much of the airsealing myself, or at least supervise it.
Thanks for any advice.

Asked By stephen sheehy | Aug 29 14
1 Answer

I understand from prior posts there are concerns with the flash foam and fiberglass insulation in terms of moisture vapor.

Would the use of proper barriers and Roxul instead of fiberglass help to abate that concern?

Asked By George Levicki | Aug 29 14
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