Electrifying your home - devise a long-term plan, and implement it one step at a time

Electrifying your home can seem like a daunting task.  I offer our family's experience below, to emphasize the importance of having a long-term plan to electrify, and making the best use of each opportunity that arises to upgrade your home using electricity.

We are almost to 100% electric in our 2,500 sq. ft., 3 bedroom home in the hills near Berkeley.  We are just waiting for the death of the on-demand natural gas hot water heater we installed 20 years ago.  I have tracked our home’s annual GHG emissions since we purchased it in 2000 – see the chart below.  Our emissions in 2023 (0.6 tonnes) were almost entirely from the hot water heater, with a tiny amount (0.04 tonnes) from our small net electricity purchases from Marin Clean Energy.  Perhaps one could argue that our house was below “net zero” in 2023, as it supplied enough electricity to our PHEV to avoid 1.3 tonnes of gasoline emissions.  But that is mixing buildings and transportation.

Observations:

1. The most important action we have taken was to improve significantly the efficiency of the building envelope in the major remodel we did in 2003 – principally new windows and more insulation in the ceilings and walls.  In 2003 we also added the on-demand water heater and the first 2.4 kW-AC solar system.
2. Full disclosure – our two sons left for college in 2010 and 2013, which accounts for some of the drop in energy use since 2010.  One of our sons has returned to live with us since 2018.
3. Adding the heat pump in 2018 had the same upfront cost as the alternative of replacing the old gas furnace and adding air conditioning, which we did not have before 2018.  At the time, I calculated that the annual operating costs for the heat pump would be $100 per year lower than a gas furnace plus central A/C. We benefitted from being able to use most of the existing ducting for the heat pump.  The heat pump has been a major upgrade in comfort – A/C, quieter, and a much better air filter. In 2018, we also did a main panel upgrade to 200A ($6,000), including running 220V circuits to the future locations for the dryer, water heater, stove/oven, and EV charger.
4. I also find our induction stove to be a major improvement – faster, safer, better for indoor air quality, and just as adjustable as gas.
5. We have tried to do the electrification measures when the old equipment fails.  We upgraded our 2003 solar system in 2022 when the original inverter failed, but donated the still-good solar panels to a non-profit that installed them on low-income housing.
6. Our battery storage has carried us through six PG&E outages in the last two years – the longest was 12 hours.
7. The expanded solar/storage system (5 kW of solar / 19 kWh of storage) is under NEM 2 – a 10 year payback two years ago, now much less due to skyrocketing PG&E rates.  Would I have installed it under the Net Billing Tariff that took effect last year?  Yes, but only because I value the backup power and think that producing your own power is a necessary hedge against the future economics and availability of grid electricity.
8. Here is a profile of our home’s imports from, and exports to, the electric grid during the four summer months of 2023 (June-September).  Our imports from the grid during the 4p-9p on-peak period are virtually zero in the summer months, as the battery picks up the evening load.  Also, we have a west-facing solar system.

9. It has not all been roses – we have had under-warranty repairs to the battery system and to the heat pump, but both are working well now.
10. It is crazy to try to go 100% electric in an existing home in a short period of time, and almost certainly not the right thing to do economically.  But it is important to have a long-term plan to do a consistent series of smaller projects to electrify, so that when the old water heater dies, you know what you want to replace it.

Now it is time for us to address our significant transportation emissions, which, as affluent Americans who like to travel, is going to be difficult.

Tom Beach