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29 Answers
AFFORDABLE Low Energy

Forget about Spray Foam
Forget about Conditioned Attics
Forget about Vaulted Ceilings

Provide a Simple(and rigid) Air Control Layer
Add Ventilation
Add a Thermal Control Layer
Add Cladding Structure and Roof Structure
Add Replaceable windows and doors and Sacrificial Claddings

Cladding structure can be as simple as furring strips

In Energy efficiency and durability | Asked By John Brooks | Feb 5 10
10 Answers
Drying to interior and paint

Hello all,
I've been learning all the Building science I can lately, and of course, that leads to questions! Hope folks here can entertain a few.
Here is one question I'd love some feedback on.
Consider a New England home that is to get outsulation, or exterior foam insulation in retrofit, or new construction. Almost all outsulation details create a vapor impermeable surface, and thus the wall is then expected to be able to dry to the interior.
How many coats of paint can a gypsum board wall take before the perm rating gets so low as to be risky?

In General questions | Asked By Nathaniel | Feb 3 10
40 Answers
What is the best wall construction in North Carolina?

I have clients wanting to build a LEED (hopefully Silver) home in NC and I keep going around about the best wall system to use that is energy efficient, cost effective and structurally sound. We (builder, structural engineer and I) have decided on a 2x4, 24" O.C. staggered wall design that is off set 12" between studs and 2" front to back. Top/sill plates are 2x6's. 5/8" sheetrock on interior, 1/2" OSB exterior with a double layer of TYVEK DrainWrap taped and sealed then spider lath and stucco finish (looking for low maintenance finish).

In Green building techniques | Asked By Sophie Piesse | Jan 26 10
3 Answers
How to make my 1966 home more thermally efficient?

I am retired and faced with very large heating bills. The weather in NJ has been quite cold and snowy for us. Our home was contractor built
in 1966. 2x4 walls with 3" on insulation. The windows are wood but not as tight as today, but the stroms windows leak to a point that we get snow
between them and the window. The house is a colonial salt box, The front is one storey, two stories in the rear. There was no insulation in the frount. I have tried to put some over the years but not sure how much good it really does.

With limited funds what is your guess as to the place to start.

In Energy efficiency and durability | Asked By Tom Spang | Feb 8 10
6 Answers
Contrast plywood window RO extensions with other method?

Hello folks,
I wonder if I could get some discussion on the pros and cons of two window methods with outsulation.
I've seen the plywood RO extenders used.
Contrast that with:
(for a 2 in exterior detail) 1 layer of foam right to window RO, with the RO then surrounded with 1x 3+/- as an attachment surface for the window flange. Second inch of foam buts up to the wood around the RO.
Similar situation for thicker foam I suppose.
Thanks!
Nathaniel

In Green building techniques | Asked By Nathaniel | Feb 3 10
19 Answers
HERS ratings & kBtu/sf/yr

Is there a direct relationship between HERS ratings and actual energy use, such as kBtus/sf/yr? Energy Star is gaining traction and making incrememtal improvements to their standards. Stretch Codes in Massachussetts pretty much make Energy Star the default route to comply. So the HERS rating is gaining traction for consumers. Its based on a scale with "0" being a Zero Net Energy Home, and 100 being a code-based home from 2003 or some such year. But I wonder how the HERS rating is related to energy use per square foot per year.

In Energy efficiency and durability | Asked By Chris Vlcek | Jan 29 10
3 Answers
Any ideas on the best way to provide a thermal break when using steel studs?

The structure is in Charlotte, NC. The wall assembly is curently drawn as 4" metal studs with Icynene insulation, 7/16" OSB fastened directly to the studs, 2 layers of felt and siding.

In Energy efficiency and durability | Asked By Doug Mcspadden | Feb 7 10
4 Answers
Attic Air Sealing

Hello,

I was wondering if there was a way to easily air seal an entire attic?

The attic is vented and unfinished with fiberglass batt insulation. The insulation and air gaps are located beneath a wood plank floor that has been nailed down. If I wanted to air seal the traditional way I would have to pull up all of the floor boards, the insulation, and then find and seal all of the gaps. Is there an easier way to to air seal over the gaps, existing insulation and wood floor?

In General questions | Asked By Graham Mink | Feb 6 10
17 Answers
Sizing exhaust only ventilation?

I am roughing in plumbing and electric and need to add ducts if we choose to use an HRV which is what I had originally planned. The house we are building has radiant floor heat in the basement and an outside air supplied sealed fireplace on the first floor so no ducts yet. Some other costs have exceeded estimates and I am thinking of using an exhaust only system to ventilate the house (Northern Michigan approx. 8000 HDD, R-40 walls, R-60 roof, hopefully fairly tight, about 2400 sf).

In Mechanicals | Asked By Donald Lintner | Feb 1 10
3 Answers
Discussion topic : Why we should consider simplicity during the design phase.

I came across a posting from Robert Bean's Healthy Heating site. I took a HRAI course that he taught on Radiant Hydronic when I started thinking about how I'd heat my house. The points he makes are somewhat aimed at hydronics designers but can apply to the whole house as a system too I believe.

In Energy efficiency and durability | Asked By Andrew henry | Feb 5 10
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