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10 Answers

How efficient are recirculating kitchen range hoods with carbon filters at removing air pollutants from cooking?

I looked at a few of these filters for the recirculating range hoods and they didn't look all that impressive, but maybe I am looking at the wrong hoods. If passive houses are using recirculating hoods how well are the hoods actually working. Clearly there is a tradeoff for energy efficiency and range hood function. Is there any specific data on this? Are there certain types of carbon filters that work better than others? I am not talking about removing moisture or CO from gas ranges but more grease and other pollutants produced when cooking with electric ranges and ovens.

In Mechanicals | Asked By Dillon Vautrin | Dec 16 15
3 Answers

Building wrap: under the exterior foam, or over?

I am building a one story, unvented crawl space, vented attic 1350sqf home in zone 7, Northern MN. Basically going REMOTE. My carpenter and I were looking at the REMOTE manual today, and we noticed Tyvek building wrap was put on the sheathing before the foam was installed. I will have 3 1/2 inches of foam, 2" resting on top and even with the outside edge of my 2 1/2 inch ICF's, (both in and out) and 1 1/2 on top of that extending down under the ground level. All 3 1/2" of foam will extend up to the top of 16" energy heel trusses with blown cellulose in the attic.

In Energy efficiency and durability | Asked By Steve Vigoren | Jul 11 16
6 Answers

SIP roof vs Truss roof

Trying to resolve a friendly dispute with a local carpenter friend.

On a 1,500 square foot roof area with 380 square feet of soffit overhang area (24" soffit).

If one would attempt this with trusses, OSB sheathing, 24" soffit overhang framing, sheathing the soffit, installing R-40 worth of insulation (spray foam). What would the ballpark cost of this be?

There is NO dispute on timeliness. The above SIP roof can be installed in 2 days and the SIP overhangs 24" on each side so it's an instant soffit. No way that a truss roof with all the above can be completed in just 2 days.

In Green building techniques | Asked By Peter L | Jul 16 16
2 Answers

Make up air for a Wood Stove in a tight, but not PH, house?

Hey guys,

I've been reading a lot about the troubles of using a wood stove in a house that is well sealed. Namely the troubles of ensuring proper makeup air to avoid back drafting, and ensuring a proper burn. Of course, it gets easier the more the house leaks, with passive house being very prone to issue with a wood stove. My trouble comes from the fact that the articles seem to treat houses of either PH, or not. That seems to leave a lot of shades of grey that aren't being discussed.

In General questions | Asked By Calum Wilde | Jul 15 16
0 Answers

How to determine COP for an ERV


I am trying to figure out the COP for ERVs. For example, if an ERV consumes 40W for 70 CFM with a Heat Recovery Efficiency of 96%, how to arrive at the COP for the energy that has been recovered for a space of 20,000 Cubic Feet.



In Energy efficiency and durability | Asked By Venkat Y | Jul 16 16
3 Answers

Rigid foam around SIPs in climate zone 4a?

I've been a passive (not pun intended) participant of these boards and this site for a while. It seems hard to catch up on it all, so hopefully my question here isn't terrible :)

I'm thinking of scraping my house off the land and building new. My goal is zero net energy. I've extensively remodeled one home including an addition myself, but I'm no professional. I do want to build and subcontract most of this home myself as well. I'm just an avid building science lover and construction enthusiast.

In Green building techniques | Asked By Michael Bender | Jul 15 16
1 Answer

Should I connect radon vent to the airtight basin lid?

I recently installed a sump basin with an airtight lid connected to interior & exterior drain tile with the intention of using it to vent radon also.

The plumbing inspector told me that I could not vent off of the basin, and that I would have to install a vertical pipe off of the interior drain tile. (could even be directly adjacent to the sump basin)

The reasoning being that in order to service the sump pump, that the radon line would need to be disconnected to remove the cover, and this vent line may not get reconnected.

In General questions | Asked By Adam Peterson | Jul 15 16
4 Answers

How can I add insulation to an insulation-board sheathed building?

We recently purchased a pre-built 12 X 24 shed. It has unfinished interior walls 2X4 stud 16"oc, exteriorly sheathed in insulation board foil-faced on the interior, painted wood siding covering the insulation board. The ceiling is sheathed in LP Tech Shield radiant barrier.

We had the previous owner/builder add a simple interior wall to divide the space into two approximately 12X12 spaces. We intend one side for gardening equipment. The other side is to perform as an art studio.

In Energy efficiency and durability | Asked By Barbara Robertson | Jul 14 16
3 Answers

Insulation Issue: Renovating EPDM low slope cathedral ceiling with flash and batt and venting problems

After researching GBA to death, I have come to the conclusion I need to ask the experts. Forgive the novel but I’d rather explain in as much detail as I can.

I am in the midst of an addition/renovation project and have hit a major snag with the roof/ceiling. I’m never going to achieve GBA nirvana, but ‘good enough’ is better than what I had. My grandfather built the house in the 1960’s and it was recently willed to me, but it’s time for changes. Kudos to my grandfather for building a freakishly strong house, but not a well insulated one.

In GBA Pro help | Asked By Robert I | Jul 15 16
9 Answers

Are sealed electrical boxes needed for the airtight drywall approach when using drywall gaskets?

I'm planning to use the airtight drywall approach to air-sealing in a single room renovation.

As I understand it with internal walls the concern is penetration into the attic. So I'm using drywall gaskets from Conservation Technology to seal the drywall at the top (and bottom plates). If the top-plates are well sealed do I need to worry about air-sealing the electrical boxes? Warm air could penetrate but not rise into the attic (or more likely in Zone 2) warm air won't ever get from the attic behind the drywall to enter the room.

In Green building techniques | Asked By James Howison | Jul 20 12
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