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24 Answers

Reflectix still claiming R4.2 for its bubble wrap - my HVAC guy is hooked

After reading up a bit on this site, I am worried that my HVAC person is installing the wrong product on the metal ductwork that he is now hooking up. As I understand it, Reflectix bubble wrap might have some benefit in a very hot unconditioned attic where the ducts are carrying cold air. But in my case, the opposite is true: the ducts are carrying hot air only and they are located in a cozy spray foamed attic. Mold formation is not an issue here (the basement is a different story, alas).

Asked By rich cowen | Mar 25 12
11 Answers

What size heat pump for a very small house?

I am getting different opinions on the correct sizing of a ductless mini split air-source heat pump. the mitsubishi rep recommends an 18,000 btu unit but the daiken rep thinks we can use a 12,000 btu unit. thoughts? it's for a 610 sq' house with 8' ceilings, r38 walls and r60 ceiling in -32 design temp. we will use electric baseboard heat for back-up. thanks!

Asked By erik olofsson | Jan 11 13
4 Answers

Please demystify cellulose grades and quality

Please demystify cellulose grades and quality ... why use one cellulose brand over another?

I need the best for dense packing, new construction dry material install and I want it clean of sulphates.

Otherwise why would I buy one brand over another. I see the following things talked about in the product descriptions:

concentration of boric acid
pure vs artificial boric acid
clean source of raw materials (paper vs cardboard)
insulation value based on fiberization and source of the cellulose
color and texture
dust content
particulate size

Asked By Oak Orchard | Mar 14 13
1 Answer

What is the most cost effective way to retrofit insulation?

I have a home built in 1996, 3800sf with a pool that has utilities running almost $700 in the summer. I live in climate zone 3A. There are two a/c units with gas heat which are not efficient at all based on the yellow energy guide sticker. There are two gas water heaters. Both the a/c and water heaters are located in the attic. The tops of the ceiling joists are not covered by insulation and there is no radiant barrier. The second floor has some walls that border attic space (like a knee wall, but for the an 9ft wall). Several rooms also has cathedral ceilings.

Asked By joseph cochran | Mar 15 13
4 Answers

A basement for my double wall dream house

I've really struggled to find a solution to all the issues of putting an economical basement under a house built to the "pretty good house" insulation plan (r60 ceiling,r40 walls,r20 basement r10 sub slab). The ceiling is easy, cellulose is cheap and energy heal trusses routine. For the walls two common choices double stud or exterior foam.

Asked By Jerry Liebler | Mar 13 13
1 Answer

Window insulation

I live on New York's Upper West Side on a low floor. Our building is offering a bulk rate on window replacement through Skyline, either Skyline Series 100 Aluminum Double Hung Windows or Marvin Clad Ultimate Double Hung Windows.

Question - which is best for SOUND insulation? Is it worthwhile inquiring about triple glazing? Many thanks.

Asked By WM hunt | Mar 14 13
1 Answer

Retrofit cathedral ceiling insulation details

Hello, I am working on a project that involves removing old batt insulation and some reframing of a 2x6 cathedral ceiling with skylights. I have read about both the vented and unvented cathedral ceiling s approaches and I understand the merit of both approaches. The ceiling I am working on has both soffit venting and continuous ridge venting and most of the rafter bays have uninterrupted communication between the soffit and ridge venting, but not all of them. Some of the communication channels are blocked by skylight framing so they either have a soffit vent or ridge vent but not both.

Asked By Cameron Clark | Mar 14 13
9 Answers

R. Carter Scott's Latest Methods

In these days of cheaper and cheaper PV, huge arrays make more and more economic sense:

18KW ! Wow. Does anyone agree with me that this is a stronger trend than Passivhaus requirements for new construction?

One design decision I would question is the propane water heater. Propane may soon become more expensive than electric resistance water heating. If a commercially proven inexpensive air-to-water split heat pump water heater were available, I'm sure they would have gone with it.

Asked By Kevin Dickson, MSME | Mar 11 13
9 Answers

How to Hang Airtight Drywall

I was watching the GBA/FHB video "How to Hang Airtight Drywall on Ceilings"...
and boy howdy .. they sure used a lot of "gooey stuff"...
I understand how the adhesive on the rafters may add to racking strength and may help avoid fastener pops.
However, I don't understand how the adhesive (on EVERY rafter) contributes to the air barrier???
It seems to me that they are putting a lot of gooey stuff in places where it is not necessary (as part of an air barrier)...

Asked By John Brooks | Nov 15 12
7 Answers

Stress question

I want to use a 2x4 wall as my load bearing wall (parallel to the ridge line) supporting trusses. Because I'm using cantilevered truss s to cover front and back porches I have unusually long truss s (56') and am building where the code requires design for 75#/sq ft snow load , I'm investigating loading and stress. The load bearing wall is the inner of a double stud wall and is sheathed on it's outer face with 1/2" plywood sealed as my primary air barrier. If I frame the wall 16" OC it can easily support the snow load + dead loads.

Asked By Jerry Liebler | Mar 7 13
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