Two questions: HPWH and Insulation

[Amy Wheeless]

Hi all,

Two questions for the group: 

(1) Have you worked with a company in the region for installing a heat pump water heater that you enjoyed working with? When I did some research on this about a two years ago, I wasn't very confident in the local market's knowledge, but we are rapidly approaching the end of life of my current gas water heater.

(2) In the interest of helping my DHP work best: I have a living space that is above an unconditioned garage, and on these cold days, you can definitely feel the cold seeping in on the floor. The ceiling of the garage is drywalled in and my house was built in 2002 so presumably there is at least a minimum amount of insulation, but have you worked with a company for blown in insulation for a relatively small job? Or do you have another suggestion for addressing this issue?

Thanks all!

Amy

[Allan Montpellier]

Amy,

Any domestic hot water heat pump that takes heat from an interior space (such as the ones with the heat pump on top of the tank you can buy at a local Home Depot or Lowe’s) are a challenge because the heat they are taking out of the air to put in the water ends up having to be made up by the home heating system.  Depending on what is heating the house, this may not be an advantage.

 

There is another option to go with a Sanden CO2 heat pump that has an outdoor unit capable of extracting heat from the outside air well below freezing, but that unit is quite a bit more cost (about $10k, depending on the electrical work required).

 

Cheers

Allan Montpellier, PE, LEED AP PRINCIPAL

PAE d: 206.596.8615 | m: 617.877.9516

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[Holly]

Hi Amy - You should definitely insulate the garage ceiling. I had this done many many years ago so don't have someone for you but PSE does make referrals and has a list of insulation contractors.  If you are not a PSE customer you could have a friend who is for referral from PSE. 

Holly Townes

[Jonlin, Duane]

Amy,

Any chance that your garage has a light fixture with a cover plate that you could remove to peek up above the ceiling?

If not, you'll want to cut out a square of drywall in the corner, or drill though with a hole saw, to find out what's there now. If you've got batt insulation in the bottom half of the joists, with foil or kraft paper backing on top, adding blown-in insulation in the top half of the joist space could create a problematic building science situation. It's all about where interior moisture would condense in winter within the assembly.

DJ

Duane Jonlin, FAIA Energy Code and Energy Conservation Advisor City of Seattle Department of Construction and Inspections P.O. Box 34019, Seattle, WA 98124-4019 P: 206.233.2781 |  duane.jonlin@seattle.gov

As stewards and regulators of land and buildings, we preserve and enhance the equity, livability, safety and health in our communities. SDCI’s offices are closed to in-person services until further notice. Visit the SDCI website and read our Building Connections blog for service change updates. Thank you for your continued flexibility and patience as we provide online services to help reduce the risk of spreading the COVID-19 virus.

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From: seattle-home-e...@googlegroups.com <seattle-home-e...@googlegroups.com> on behalf of Amy Wheeless <amy.wh...@gmail.com>

Sent: Tuesday, November 10, 2020 11:21 AM
To: Western Washington Home Electrification <seattle-home-e...@googlegroups.com>
Subject: Two questions: HPWH and Insulation

 

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[Amy Wheeless]

Hi all,

Looping back to this - has anyone had recent success with installing a heat pump water heater (replacing a gas water heater in a garage)? We had an assessment with a company, who has since ghosted us (too many space heat pump / AC projects in the queue, I suspect). Thanks!

[Brian Gix]

Hi Amy,

I had a heatpump water heater installed last spring.  I *intended* for it to go in the garage, but ended up placing where our old one was in the main basement (same "floor" as the garage, but about a foot higher, and on the other side of a wall). One problem with installing any water heater in a garage is that it must be raised 12-18 inches off the ground due to current codes....   Garages are assumed to be potential gasoline storage locations, and thus anything with a hot surface (including heat-pump water heaters) are considered ignition danger surfaces, that must be raised above any potential gas fumes.  Since I was losing about 18 inches of vertical  space, and I needed at least 12" for the air intake on top, we had to change from our desired location.

That said, I was able to *exhast* into the garage so that I don't lose so much basement heat in the winter.

--Brian

To view this discussion on the web visit https://groups.google.com/d/msgid/seattle-home-electrification/CACpymSisRtGYXMp%2BoY4ER4zVSxsQawgHXmsv9ShT1f4rcJ4yyA%40mail.gmail.com.

[Jonlin, Duane]

...of course, exhausting cool HPWH air into the garage can result in an equal amount of cold outside air infiltrating into the house elsewhere.

	Duane Jonlin, FAIA Energy Code and Energy Conservation Advisor City of Seattle Department of Construction and Inspections P.O. Box 34019, Seattle, WA 98124-4019 P: 206.233.2781 |  duane.jonlin@seattle.gov
	As stewards and regulators of land and buildings, we preserve and enhance the equity, livability, safety and health in our communities.

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Sent: Tuesday, March 1, 2022 1:04 PM
To: Amy Wheeless <amy.wh...@gmail.com>
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Subject: Re: Two questions: HPWH and Insulation

 

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[Amy Wheeless]

Thanks all! Our current gas water heater is in the garage (and elevated), so should be no trouble to put the HPWH in the garage, and we were planning to vent outside. However, finding someone who will (a) respond to us and (b) not convince us to replace with gas, has been more of a trouble :) Any recommendations welcome!

[Jonlin, Duane]

sure - just keep in mind that the HPWH is considerably taller than your existing gas unit.

	Duane Jonlin, FAIA Energy Code and Energy Conservation Advisor City of Seattle Department of Construction and Inspections P.O. Box 34019, Seattle, WA 98124-4019 P: 206.233.2781 |  duane.jonlin@seattle.gov
	As stewards and regulators of land and buildings, we preserve and enhance the equity, livability, safety and health in our communities.

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From: Amy Wheeless <amy.wh...@gmail.com>
Sent: Tuesday, March 1, 2022 1:21 PM
To: Jonlin, Duane <Duane....@seattle.gov>
Cc: Brian Gix <bria...@gmail.com>; Western Washington Home Electrification <seattle-home-e...@googlegroups.com>

[Brian Gix]

> ...of course, exhausting cool HPWH air into the garage can result in an equal amount of cold outside air infiltrating into the house elsewhere.

Yeah, I suppose. We literally "don't live in a vacuum. But it has resulted in our laundry room not feeling like a deep freeze, and it *does* seem to keep my growlers from Georgetown (stored in my garage) at an acceptably drinkable "Celler Cool".

[Brian Gix]

Our main contractor was Washington Energy Services (yeah, the Natural Gas guys) and the subcontractor was bobsheating.com .

[Tom Balderston]

The code in 2002 was R-30 so  it should have that,  but no telling how well or badly it was put in.     You might try  Clean Crawls   or Insulation NW.       In this situation it is possible to do "dense pack cellulose"  which  can compress the old insulation out of the way  and fill the cavities completely.    

You'll want to  pay attention to air sealing as well.    any light fixtures or holes in the drywall  should be caulked or foamed well.    Dense Pack  also helps  to reduce air leakage. 

tom