Heat pump water heaters are going to be much more commonplace.

With the new energy codes in place in Washington State, if you apply for a building permit and it is submitted after February 1, 2021 you will be required to meet the 2018 Washington State Energy Code (WSEC).  This means getting enough “Energy Credits” to meet the requirements of your home based on size. For most home you are going to need either 3 or 6 credits (Homes up to 5000 sq ft)

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From the Washington State Energy Code-

WSEC R406.3 Additional energy efficiency requirements.

Each dwelling unit in a residential building shall comply with sufficient options from Table R406.2 so as to achieve the following minimum number of credits:

1. Small Dwelling Unit: ……………………………………………………………………………….3.0 credits Dwelling units less than 1500 square feet in conditioned floor area with less than 300 square feet of fenestration area. Additions to existing building greater than 500 square feet of heated floor area but less than 1500 square feet.

2. Medium Dwelling Unit: ………………………………………………………………………….. 6.0 credits 

All dwelling units that are not included in #1, #3 or #4.

3. Large Dwelling Unit: ……………………………………………………………………………… 7.0 credits Dwelling units exceeding 5000 square feet of conditioned floor area.

4. Dwelling units serving R-2 occupancies: …………………………………………………..4.5 credits

5. Additions less than or equal to 500 square feet:………………………………………… 1.5 credits

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Here is a little primer on some definitions-


DWELLING UNIT.

A single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation.


310.5 Residential Group R-3 (this is where the single family home is defined in IBC)

Residential Group R-3 occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I, including:

• Buildings that do not contain more than two dwelling units
• Boarding houses (nontransient) with 16 or fewer occupants
• Boarding houses (transient) with 10 or fewer occupants
• Care facilities that provide accommodations for five or fewer persons receiving care
• Congregate living facilities (nontransient) with 16 or fewer occupants
• Congregate living facilities (transient) with 10 or fewer occupants
• Lodging houses with five or fewer guest rooms

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So back to our story. One great way to get some of the energy credits needed is to install a Heat Pump Water Heater (HPWH).

The heat pump water heater will need to meet the Advanced Water Heater Specification.  For the these Heat Pump Water Heaters that I am discussing are listing in table 1 of the specification guide.

https://neea.org/our-work/advanced-water-heating-specification

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Based on the tier of of the electric heat pump water heater you purchase you can get 1.5 credits for a tier 1 type or 2.0 Credits for a tier 3 type of heat pump water heater.

Most are opting for a tier 1 Heat Pump Water Heater and getting the 1.5 credits.

So with that said there is a side effect of these Heat Pump Water Heaters. When they are working they will exhaust cool air as they extract heat from the environment to heat the water in the tank.

In the winter this can be problematic if the Heat Pump Water Heater is located in a garage or in the conditioned space of the home.

If you live in a colder or cooler climate this can be problematic if the Heat Pump Water Heater is located in a garage or in the conditioned space of the home. You can make your garage or indoor space pretty darn cool. In this case you will want to duct the exhaust to the exterior of the home to exhaust that cool air being discharged.

If you live in a climate where you are cooling part of the year, one solution is to install a duct system with dampers to move that cool air to the exterior of the home.

For those that live in Eastern Washington or other warmer climates, having that a dual duct system with a damper that can move the cool air indoors in the summertime when air conditioning is required, and to the exterior of the home when we are in heating mode for the winter. This may be a great way to take advantage of extra cooling BTU’s produced by the HPWH.

Heat Pump water heater can be have a pretty cool exhaust temperature depending on the home temperature. Here is an example where the HPWH was installed in a bedroom closet.

Well this would be all well in good but as you can see from the IR picture below this can create a chilly closet and room. Due to a lower indoor temperature at the time of this home inspection I was getting an exhaust temperature of around 25 degrees. This will put a little frost on the old pumpkin and maybe your toes.

So exhausting this HPWH to the exterior would be well worth it.

“One must combat ceaselessly. When one has destroyed an error, there is always someone who resuscitates it”
 Voltaire

If you find any errors or have additional information that would expand on any code, building standards or manufacturer requirements please let me know.

NCW Home Inspections, LLC  is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…  

Your Wenatchee and Chelan Professional Real Estate, Home and Structural Pest Inspection Service

Coordinator & Instructor- Fundamentals of Home Inspection-  Bellingham Technical College

Former WA Home Inspector Advisory Licensing Board

www.ncwhomeinspections.com                                                   509-670-9572

 You can follow me on Facebook, Twitter, Google+ and on my website Blog.

 

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If you find any errors or have additional information that would expand on any code, building standards or manufacturer requirements please let me know.

NCW Home Inspections, LLC  is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…  

Your Wenatchee and Chelan Professional Real Estate, Home and Structural Pest Inspection Service

Coordinator & Instructor- Fundamentals of Home Inspection-  Bellingham Technical College

Former WA Home Inspector Advisory Licensing Board

www.ncwhomeinspections.com                                                   509-670-9572

 You can follow me on Facebook, Twitter, Google+ and on my website Blog.

 

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