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1 Answer

Not a question.. Listen to Martin Holladay on FHB podcast

I listen to this podcast every Friday and Martin was the feature guest (2nd time around for him) this week. It's always nice to put a voice with the name.


Excellent listening !!

In General questions | Asked By John Clark | Mar 16 18
7 Answers

This post is not about building science

The topic here has nothing to do with green building, so feel free to skip it and look elsewhere for a more relevant post.

My sister Meg spent a year living on the island of Lagonav in Haiti, where she volunteered as a teacher in a local school. Friends of hers on the island, including Jeanes, an agronomist, and Balaguel, Eligène, and Carlot, agricultural technicians, as well as two teachers, a school director, and a local government official, have set up an agricultural development project.

In General questions | Asked By Martin Holladay | Mar 15 18
9 Answers

DWHR and HPWH vs Electric, Total Efficiency?

So it's well known that a Heat Pump Water Heater (HPWH) is far more efficient at heating water than a standard electric water heater, but what happens when we look at the entire system top to bottom, including Drain Water Heat Recovery (DWHR) as well as the building's main heat source?

In Mechanicals | Asked By Lance Peters | Mar 15 18
3 Answers

Real world quotes on HFO blown foam, anyone?

A guy in my office is (finally!) getting around to insulating the basement of his 1920s cinder block (real cinder blocks, not CMU) foundation bungalow. After getting some quotes using different approaches, he's opted to do it with 3" of HFO blown closed cell foam (~R20-ish) .

There is about 950 square feet of wall to be foamed, x 3" = 2850 board feet of foam. The line item for the foam portion is about $4K, which would make it $4000 / 2850 =

$1.40 per board foot for R7, or about 20 cents per R-foot.

In General questions | Asked By Dana Dorsett | Mar 15 18
6 Answers

Can the concrete slab be eliminated in a super-insulated slab?

The Passive House Build designed by Steve Baczek has a 4" concrete slab sandwiched between 10" of foam below and 1 1/2" of foam and p.t. 2 x 4 sleepers above. Featured in the Nov/2016 issue of JLC was a home designed by Mr. Baczek that had a basement floor that consisted of 2 layers of 3/4" Advantech plywood subfloor over 6" of foam. The 6" of foam was above a 2" layer of pea stone, which was above a 6" layer of 3/4" stone.

In Energy efficiency and durability | Asked By user-7002058 | Mar 14 18
4 Answers

Is this new insulation worthy of a GBA article or news item?

I saw this on CleanTechnica

New Material Made From Wood Is Biodegradable Super Insulation

In Green products and materials | Asked By Alan B | Mar 15 18
8 Answers

Heat-pump water heater: Air volume, etc.


Lots of good information here about Heat Pump Hot Water Heaters, thanks! My situation is unique, so I thought I'd get some feedback before I pull the trigger and purchase 2 Stiebel Eltron 80-gallon units to install in place of 4 40-gal resistance hot water heaters servicing 4 2-BR units in a multifamily building.

In Mechanicals | Asked By Tobeywan | Mar 13 18
5 Answers

Is it Safe to Sandwich Rim Joist Between Rigid Foam and Vapor-Impermeable Flashing?

The contractor on my renovation project has put a thick, flexible, black plastic or rubbery flashing material (York Vascoseal) around the bottom of the wall where it meets the CMU crawlspace. It is roughly the same width as the rim joist and covers it completely. He said the it pleases the inspectors, is required behind deck ledger boards, and helps protect the bottom of the house from splashes and whatnot, so they just run it around the entire house for good measure. I assume it is vapor impermeable just by inspecting it, due to its thickness.

In Green building techniques | Asked By Gordon Franke | Mar 15 18
7 Answers

Using supplemental heat pump hot water heater as AC+"battery" during summer

Hello Green Building Advisor,

I have a situation in my home where the (gas) hot water heater is on the 2nd floor in an area that is roasting (80F+) for six months of the year. In fact, the 2nd floor hot water heater is in the laundry room adjacent to two bedrooms that also tend to overheat.

I am intrigued with the idea of using a heat pump water heater as an AC unit with a "battery" (the tank) that heats during the day and which I can heat exchange with my (true) hot water heater for showers in the evening/morning.

In Mechanicals | Asked By CJ_Los_Alamos | Mar 14 18
7 Answers

Air barrier and insulation - Zone 3A Atlanta

Good morning all. I’m loving this site, so much good info here. It’s really helped in choosing the right contractors for a few projects now.

I’m hoping someone can help shine some light on some ways to best approach air sealing and insulating our 1950's home in Atlanta as we replace the siding. We’ve opened up some walls and look to be faced with a few setups:

1. On the original house - From outside to inside looks to have aluminum siding —> paper/foil barrier —> wood siding —> plywood sheathing —> tar paper (on INSIDE of wall) —> wall framing

In Energy efficiency and durability | Asked By pofe333 | Mar 6 18
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