All Electric Condo Renovation – replacing ducted heat pumps with ductless.

Our All Electric Home

I know from our experience that one can a) use heat pumps with no fossil fuel backup in our New England climate and b) taking certain measures (those “variables”!), can make all electric heating (and cooling!) “affordable”.

We live in a good situation for home energy comparisons — a condo development with 26 almost identical two story duplexes built in the mid 1980s with all electric heating (no gas or oil).

Each home had two big heat pump compressors at the side of the building with one heat exchange unit in the basement serving the first floor and one in the attic serving the second floor, both providing forced hot (or cold) air through ducts. There were also a few (we had three) baseboard resistive heat units installed in areas hard for ducts to reach. The old heat pumps could also use resistive (expensive) heating if they could not keep up.

Around 2014, our Eversource bills told us we were consuming far less electricity than our average nearby neighbors.

No doubt this was because we already did these:

1- Had energy efficient lights and appliances
2- Turned off items when not needed, including light polluting outdoor lighting
3- Dried our clothes on drying racks rather than in the dryer
4- Kept the thermostats low and wore warm clothes in the winter
5- Opened windows in the evenings and closed them in the mornings during cool summer nights, rather than than using the AC
6- Avoided wasting hot water when showering or washing dishes
7- Disconnected the wiring to our inefficient resistive baseboard heating units

All the buildings have had Mass Save coordinated improved air sealing and attic insulation installed, an important measure.

In 2015 we sought to do even better, by installing a single ductless mini split and stop using our ducted system at all.

We installed a single 15K BTU ductless mini split in our living room, an open area near the kitchen. (cost after rebate about $3,600) The installer argued this would be insufficient for the whole house but we wanted to try it anyway.

After 2015, we used only this one mini split for heating and cooling for the whole house. We kept the living room at about 68 degrees in the winter. Enough heat drifted up the stairs to the second floor to keep it cool but usable for two bathrooms, office and bedroom at around 62 degrees in the winter. We had absolutely no heat in the basement which is cool (but not close to freezing) in the winter, being largely below ground. We were and are satisfied.

With that change to the mini split, our electric bill was 28% lower for 2016 than it was for 2014.

If we had chosen to put a mini-split in each major room, the installation cost, after rebates, would have been much higher and the operating cost would also have been higher.

We know we are paying 1/2 or less of what some of our condo neighbors are paying, as some have shared their electric bills with us. Our biggest electric bill of the past year was for January 2023 for $308. One neighbor paid over $1,100 for that month! None have chosen to replace their ducted systems with mini splits.

Other factors to consider:
• We are just two retired persons
• Philosophically, we are fine with a bit less than 100% comfort.
• We do not inhabit the basement
* Larger families would probably need more mini splits and use more energy • Our 1st and 2nd floor lived in area is 1,200 sq feet.

In Conclusion

Our “minimalist” approach may not be for everyone, but it was very affordable and we feel good about having less of a carbon footprint than probably any of our nearby neighbors. If one used this minimalist approach switching over from gas heat to a mini split, the outcome should be the same

Note: Our percentages and numbers have been adjusted to remove the impact of the two EVs we charge at home. Also, once in a while as a treat for the coldest winter evenings, we run our wood stove for a few hours, but that has been a constant over many years and would not affect the reduction numbers we saw in 2016.