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27 Answers

Which system to install: a conventional ducted heat pump or 7 minisplits?

I'm building a 3300 sqft house with blower door test around 1 ach, R31 walls, and a R 60 vented attic in eastern PA (Zone 5). I'm considering using the minisplits from Fujitsu.

My one quote for the conventional system came in for a 3-ton system after he put the house through his software and the other quote was for 7 Fujitsu 9RLS minisplits. It might be overkill with that number of units. I will be ventilating the house with a ultimateAir ERV.

In GBA Pro help | Asked By john bell | Jul 29 12
16 Answers

The most Underappreciated Building Assemby

A Recent FHB Lstiburek Article
( free at BSC site)
A good article.
And a very interesting clue to affordable/buildable high performance....
Lstiburek: "A vented attic, where insulation is placed on an air-sealed attic floor, is one of the most underappreciated building assemblies that we have in the history of building science."
I think the Vented Attic HAS been neglected by most.(but not all)

In Energy efficiency and durability | Asked By John Brooks | Jul 24 11
8 Answers

Need help with spray-foam insulation

We are building the house, and I was going to put spray-foam insulation on external walls 2x4 covering 3" with foam. But my builder advises against it, saying that there are potential mold issue. we leave close to Detroit (as weather goes).

Thank you in advance for your help.

In Energy efficiency and durability | Asked By Alex P | Aug 15 12
22 Answers

Extension jambs for in-swing doors on double wall construction?

Our home has double 2x4 walls, 10" thick rough frame. Windows were easy to find, they can be hung on the outer frame (we went with Serious 725 series). But we'd like the doors to open inward and are having trouble finding doors with such deep extension jambs. Any ideas out there? We are in central New Hampshire.

In General questions | Asked By janet bergman wilkinson | Aug 9 12
1 Answer

Flash and batt for attic floor

I live in zone 7, old construction. Currently the attic i floor is insulated with fiberglass batts, obviously creating lots of problems with heat loss and ice forming on the roof under certain conditions. The roof itself isn't insulated, so it's a ventilated attic.

In Energy efficiency and durability | Asked By Oleg Anikin | Aug 16 12
1 Answer

Seal Flex Duct Connections With Fire Block Spray Foam?

Is it acceptable to seal flex duct connections (at supply plenum, ceiling boot, where main supply lines branch into multiple lines) using a can of fire blocking spray foam? Thank You.

In Energy efficiency and durability | Asked By Randy Ransom | Aug 15 12
28 Answers

Cities are not green

How can the "experts" continue to say living in high density is the "green" way versus living in towns? I just attended a town meeting. Our town is staying under budget. Our town taxes in total average one half to one quarter that of cities.

Cities, not towns are going bankrupt or raising their taxes some as much as 78%!

In General questions | Asked By aj builder, Upstate NY Zone 6a | Jul 11 12
3 Answers

Cool roofs and solar PV panels

Does anyone know of studies on the effect of PV panels on the rooftop solar heat gain calculation? I imagine there's some shading, some absorption and emittance from the dark colored panels, and overall a small effect due to surface area, but haven't seen any studies...

In Energy efficiency and durability | Asked By Brenden McEneaney | Aug 7 12
7 Answers

Can I spray foam the inside skirting of my house?

I am trying to keep my water tanks from freezing - my water tanks are under the house. Would the house shift from this? The house is sitting on wood pads.

In General questions | Asked By mike spence | Aug 13 12
6 Answers

Marc Rosenbaum will teach an online course on NZE homes

Beginning October 1, 2012, energy expert and engineer Marc Rosenbaum will be teaching a 10-week online course on how to design and build net-zero-energy homes.

Marc Rosenbaum is the real deal: an expert who knows what he is talking about. If you're interested in the topic, you couldn't find a better teacher.

Sponsored by the Northeast Sustainable Energy Association (NESEA), the course costs $895 (or $795 if you register early). For more information, see Zero Net Energy Homes.

In Energy efficiency and durability | Asked By Martin Holladay | Aug 9 12
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