Heating solutions in the PNW

[Ben Anderson]

Hello, I am finishing some a remodel on a 1911 home with an ADU in the Seattle area.

The home was previously heated by two gas stoves with very little ducting. As part of converting the upstairs unit to a 2 bedroom, I had to remove the upstairs stove. The upstairs (~1000 sq ft) is heated by 3 electric baseboard heaters and has been at a pleasant temperature at all times of day.

The plan for the downstairs ADU (also ~1000 sq ft) was to do a combination of baseboard heaters and the existing system, however the existing system is not working and my contractor says was not installed properly. I have been living downstairs with 2 baseboard heaters, and the mornings are rather chilly, but the temperatures are already fine. I'm considering several options for heat and would like to hear some other opinions:

Option 1: Remove old system downstairs, add a third baseboard heater downstairs ~$100

Option 2: Install new gas stove downstairs, fix chimney, use existing ducting, possibly use no baseboard heaters ~$3500

Option 3: Install a ductless mini split system for upstairs and downstairs ~ $7500

It's fairly typical for homes in my area to not have AC so the mini split system would be a good selling point. I am a little concerned about the costs of running a bunch of electric baseboard heaters (I'm house hacking right now and plan on splitting utilities with the tenant for the 1-2 years I live here). I understand that long term it will be the tenant's responsibility, but I imagine it will impact what I can charge/tenant's inclination to stay.