I am intending on replacing my 50+ years old gravity furnace. This may appear straightforward, however I have an in-law apartment in the basement that I rent which needs upgrading. Currently I have a gas wall heater there, but according to current San Francisco codes, I cannot just replace it with the same.

Heating contractors have suggested a two zone system with a separate zone for the apartment, but other contractors have told me that two zone systems never work properly.

I'd appreciate any opinions or guidance. I'd prefer to stick with gas heating rather than an electric baseboard.

Thanks,
drdevi

If set up properly two zone systems are great, we do it very often in large homes and the homeowners love it. Also around here you can't zone an apartment because they can not share common air, 2 seperate systems need to be installed with their own ductwork.

If set up properly two zone systems are great, we do it very often in large homes and the homeowners love it. Also around here you can't zone an apartment because they can not share common air, 2 seperate systems need to be installed with their own ductwork.

Hi, thanks for your response.

Yes, the same holds true here in San Francisco. However, one contractor said that I could connect in a Carrier Infinity Air Purifier with the 2 zone system, which would take care of the shared-air thing. Would that stand up to the code requirement?

Hi, thanks for your response.

Yes, the same holds true here in San Francisco. However, one contractor said that I could connect in a Carrier Infinity Air Purifier with the 2 zone system, which would take care of the shared-air thing. Would that stand up to the code requirement?
Not here, but you codes are probably different. Check with your local HVAC building inspector.