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4 Answers

Do heat pumps and super insulation complement or compete with each other?

After reading the article on "how much insulation is too much", I found Marc Rosenbaum's stats on 11 cold climate house configurations interesting. He points out that the difference in energy savings is very small between a minimally insulated and poorly air sealed house and a super insulated and very tight air sealed house. This is because he starts with an 2.5 cop heat pump and a heat pump domestic water heater. He sets the miscellaneous loads (appliances and lighting) at 4800 kwh year. The domestic hot water at 1850 kwh year, and the only variable is space heat.

Asked By ven sonata | May 29 16
33 Answers

Improvement on the Lstiburek Ideal Double Stud?

Hi all. Please see the attached PDF of a variation on Joe Lstiburek's Ideal Double Stud Wall design (http://www.greenbuildingadvisor.com/articles/dept/building-science/lstib...).

I am trying to go for something a bit quicker and less labour intensive to build, but that is still very vapour open to the exterior (and occasionally interior) to overcome the usual double stud wall shortcomings.

Please fire away with critiques. The main problems I see are:

Asked By Burke Stoller | May 6 16
1 Answer

Insulating walk-out basement

I'm insulating a walk-out basement in a new construction. The house is of a double wall design, and will be filled with dense pack cellulose. I understand that for the foundation walls that I can not apply cellulose directly, however I had thought that if I apply a layer of closed-cell either sprayed or laid in in sheets then I should be able to fill the rest of the cavity with cellulose, assuming that there is no concrete exposed. My question is how many inches do I need to use to assure I have no problems with the cellulose?

Asked By Geoff Frood | May 29 16
35 Answers

Best exterior wall design within standard 2x8 dimensions

I have been reading several of the GBA posts and articles and I don’t seem to locate the answer to my question so I wanted to drop you a line by email.

I am located in Saskatchewan, Canada and currently have a house under construction that is well under way. That being said I won’t over complicate it with detail but the house is not a high efficiency design and I am not and don't pretend to be knowledgeable on a lot of points that are covered on GBA.

Hhowever, this is what i have

Construction detail:

Southeast corner of Saskatchewan, Canada 15 miles north of North Dakota

Asked By chad online:) | Feb 21 16
18 Answers

Has anyone ever kept sheathing warm and saved labor costs this way?

There are a handful of manufactures who make rigid insulation with OSB bonded to the surface (like a SIP with OSB on one face only. But SIPs are not the topic in this post). This assembly is commonly used for roofing but I was contemplating using it backwards as exterior wall sheathing. By backwards I mean fastening it onto the studs so the OSB is touching the studs and the foam is on the outside. By doing this, the osb is kept warm and that desirable thermal break is incorporated as well (after all thats generally the reason to put rigid on the outer face).

Asked By sean stewart | May 22 16
1 Answer

Northern bias

I grew up in Iowa, lived most of my life in New England, but now live in the hot humid south. I think you need to focus more on climates other than the cold north. Contributors like Curt Kinder were very useful to me a couple of years ago -- a person who had migrated similarly, but unlike me ( an amateur ) was a pro in his business -- HVAC. Suggest you do what you can to get hot and humid more often, and more important, encourage contributors like Curt Kinder, a person who writes well, and has real-world experience, to re-engage.

Asked By Michael M | May 28 16
18 Answers

PEX A vs. PEX B

I am obsessing over which pex to use for a whole house manifold installation. The choices are pex-a (uponor) vs pex b (viega).

Uponor seems easier to work with, less kinking, better flow etc.

What I am most concerned with is:

1.longevity (this is my forever house)
2. safety (leaching of chemicals into drinking water)

I am on a well.

Any input as to the longevity and safety of these two different types of pipes?

Dean

Asked By Dean Sandbo | May 26 16
11 Answers

Windows -- Pretty Good or better in Western Colorado

I am looking for windows for a Pretty Good house I am preparing to build in Carbondale, CO at an elevation of about 6,200 feet. Climate zone is 6B. We get lots of sun here and large diurnal temperature swings, year round. I don't know of any homes in town with air conditioning. I'm looking at Pretty Good insulation levels, R-5-10-20-40-60 and about 6 to 8% south facing glass with fairly low thermal mass -- partial tile floors and 5/8 drywall. Windows on the north and west will be limited. I've heard that 4% overall operable glass is a reasonable target.

Asked By Pat Kiernan | May 27 16
10 Answers

Sun Pump solar heat pump

Does anyone have experience with the Sun Pump solar heat pump, either with the product itself or dealing with the company? It's a relatively new company located in Vancouver BC.

Asked By Peter Schonherr | May 19 16
16 Answers

How to vent a flat roof

Designing a home in Santa Fe, NM. Roof will be TPO over open web trusses. Pitch is 1/4" / ft.
Parapets all around. Insulation will be blown-in cellulose. R value to be 50. How do I vent the roof cavity above the insulation? I could use mushroom caps. I've done the calculations and I need quite a few. How much air space is required above the insulation? 2", 3" or more? Also planning on installing a radiant barrier between the tops of the trusses and the sheathing. When I build crickets over the sheathing will I need to provide air ventilation for the cavity? Thanks!

Asked By jack robinson | May 14 16
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