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6 Answers

Floating slab vs monolithic - energy performance

I am deigning a house with an fpsf slab on grade (zone 5) under a 2x6 stud wall with 4" of Roxul comfort board IS outsulation. I like the ease of pouring the monolithic in one shot, but have concerns about it's thermal performance.

My two concerns are 1. metal fasteners attaching the slab-edge insulation and concrete board creating a thermal bridge. 2. metal flashing above the slab edge insulation contacting the outside top corner of the concrete and providing another thermal bridge around the entire perimeter of the house.

In Energy efficiency and durability | Asked By Michael Iacona | May 14 16
6 Answers

Basement mold and possible solutions--full post!

Hello,
Whoops - last post didn't include the details!

I've read a lot on this site on this issue and want have a few lingering questions. Thanks for all the info here already!

In Green building techniques | Asked By Melinda S | May 15 16
19 Answers

Working a wood stove into my hot water system

Hi all,

I'm looking for thoughts on how to tie a wood stove into my DHW system in a new house I'm building. Some background is needed though...

In Mechanicals | Asked By Jay Hersh | Aug 9 11
4 Answers

Sub-slab drainage stone size

I know the typical recommendation is 3/4" no fines. Foundation contractor and stone supplier are recommending I use 1.5". Foundation contractor is trusted and has used product a great deal including under some very dry basements that I've been in. Stone guy says he has 3/4 no fines - but it's more money for no gain. I have seen the product they are calling for; it's a mix of ragged and round stone that would surely drain very well. I can tractor stone in, so will be able to minimize trying to stick a shovel in it. SDR 35 interior footing drains.

In GBA Pro help | Asked By Jim Tyler | May 13 16
4 Answers

XPS brands: Dow; Owens Corning; Pactiv/Kingspan?

I would appreciate feedback on the brands of XPS relative to one another.

I'll be installing a double exterior layer next week. Right now I can buy 3/4" sheets of the Pactiv/Kingspan XPS sold by Lowes for $13.57 a sheet (4x8).

Has anyone had any negative experience with the Pactiv/Kingspan foam?

Thanks!

In Energy efficiency and durability | Asked By Bill Daugherty | May 5 16
6 Answers

Does the EER matter on a ductless mini-split?

The Energy Star requirements for ductless mini-splits are identical to split air-source heat pumps, with SEER, EER, and HSPF efficiency standards. However, several utility programs have chosen to drop the EER requirement (e.g. Energize Connecticut).

Does the EER matter on a ductless mini-split? Why or why not?

Thanks!

In Energy efficiency and durability | Asked By Whitney Larsen | May 13 16
8 Answers

Dense-packed cellulose wall insulation

Hi everyone, bit of theoretical question here. Could a wall be designed that would allow cellulose to be blown in at a lower density than "dense-packed" and any settling that will occur is accounted for in the design? (see below). Obviously cavities below windows would need to dense packed. I guess what I am asking here is does dense packing improve wall performance in other ways other than R-value vs loose filled?

Thank you

In Green building techniques | Asked By Oliver Neumann | May 12 16
3 Answers

Strategy to insulate interior wall exposed to roof cavity

My home is a brick colonial style in climate zone 3. Our main roof is 4-side hip and is encapsulated and contains our upstairs HVAC system. A secondary elevation is over the garage and adjoins the wall of the two south-most bedrooms. This one is 3-side hip with a flat top (architect bad a math) and is ventilated with soffit vents and a powered fan tied to a HA system.

In Green building techniques | Asked By Dan Geist | May 13 16
5 Answers

Dow Powerhouse Solar System 2.0 PV shingles

An architect I know asked about these (www.dowpowerhouse.com/Solar%20System/). I found Martin's review from 2012, and I wonder if anyone has more recent experience?

Thanks,

Andy

In Green products and materials | Asked By Andy Engel | May 12 16
32 Answers

Transoms and Ductless Minisplits

Hello,

I am trying to heat and cool my second floor with one 12,000 btu ductless minisplit. I have heard that this is possible if I keep the bedroom doors open during the day to facilitate circulation of the hot or cool air.

However, does it get uncomfortable quickly in the night when the doors are closed. If so, I was thinking of putting in operable transoms over the doors. The only problem is they are kind of expensive (~$275 from transomsdirect.com). Attached is my floor plan. I will be putting ceiling fans in each bedroom so maybe the transoms would be overkill?

In Green building techniques | Asked By Jimmy Nguyen | Mar 10 16
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