EXAMPLE OF HOUSE CONVERSION TO ZERO EMISSIONS

New walking-tour video of home electrification process: https://youtu.be/d2luJbFGGdc

HVAC conversion to heatpump

Water heater conversion to heatpump

REFERENCES:

https://smarterhouse.org/water-heating/replacing-your-water-heater (Great overview for replacing your water heater)

https://hotwatersolutionsnw.org/ (Great site for Oregon and Washington State residents)

https://neea.org/img/documents/qualified-products-list.pdf (If you want to geek out comparing models)

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how to achieve a zero carbon home

A highly informative presentation in Berkeley, CA in February 2019 where the workshop leader, Sean Armstrong, explained and completely demystified the roadmap of how we could achieve a zero carbon home. (Watch Sean’s workshop video and download his PPT presentation)

SUMMARY: As a challenge last year I retrofitted my home in the San Francisco Bay Area to remove all fossil fuel appliances and go all-electric. Although our cold winter isn't like yours, you might get some ideas from the Blog I wrote about my experience here. This is on pulling out our 2 gas furnaces and replacing with 8 minisplits:
https://www.sustainablelafayette.org/single-post/home-electrification-part-4-selecting-and-installing-a-heat-pump-heating-cooling-system

For our HVAC, we installed Fujitsu Halcyon Mini-Split, ductless units. They have a product line that works at 200-300% efficiency in my climate zone, but also still at 100% efficiency at -15F (See page 14 of this doc). As other posters have mentioned, if you have only a handful of days at less than -15F, you could use portable units in the rooms just for those days, so that you can enjoy the great economics of heat-pump technology for most of the winter + summer
https://www.fujitsu-general.com/us/resources/pdf/support/downloads/halcyon-2020-full-line-brochure-02.pdf

My other thought is to call 3 different heat-pump HVAC vendors (including Fujitsu and Mitsubishi dealers) as everyone can offer different strategies and it's a good learning experience to compare. Everyone will be a bit biased to what they are accustomed to sell, not necessarily to what we customers want or need! So for this newer technology, try to get a wider range of proposals

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A BLOG ENTRY: Congratulations on moving to a cleaner heating option. When it comes to cold climates, I always think, what would they do in Canada? :-) This article covers the options well: https://www.cbc.ca/news/technology/greener-heating-1.5429709

The key takeaways are there are really cold weather heat pump options and an electric furnace is a good option to consider as well.

I am in Chicago, and we plan to go with one of these options. We already started to use heating panels in select rooms so we could use less methane for rooms we are not using. For example, we have a heating panel on a timer that warms up that our bedroom in the evening around bedtime and in the morning for when we wake up.

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EXAMPLE in Boulder, CO (12/21/2020: I am in Boulder CO, a hard USDA zone 5.  In the polar vortex a few years ago we were at -10 for 4, maybe 5, days.  We have an ASHP made by Mitsubishi.  We went right through the vortex.  Our system is rated to cut off at -17.  Other manufacturers have cutoffs as high as -5.
We live in a 60-year-old home that had a ducted gas furnace.  We replaced the gas furnace with an outdoor compressor and an air handler in place of the furnace.  The air handler has resistive coils that come on when the temperature is so cold heat cannot be produced.  The coils have come on a handful of times in the 2 years we have been operating.
How often do you experience this outlier cold?  If it is not so common you could think about supplemental heat in those times.
In fact, part of the idea of moving to electrified heat is to use less energy.  It turns out that gas furnaces have been over-engineered forever simply because homes were energy inefficient and unnatural gas was cheap.  So part of the game plan moving to renewable services is tightening up the house so you can right-size the system
And, I am pretty sure you are aware, ASHP technology is like your refrigerator with the ability to heat added.  So for the cost of your heat, you also get air conditioning.
Finally, the coefficient of performance for ASHP is at around 3, while your most efficient gas furnace will be around 0.9.

I am a decarbonization bigot.  So I cannot justify burning fossil fuel simply because there are 5 times a year when it is so cold.  We also use ASHP technology to hear our water.  We have removed the tailpipe, and the gas-line, on the property.  I advise you to do so as well.