Baseboard and convectors

Bob Aluska

I'd like to know if it's OK to mix convectors with regular baseboard in the same zone on my heating system? I've visited The Wall for many years as a homeowner...not a heating professional, just to learn what makes these things tick. Back in '99 I learned of the Ergomax indirect here and got one and love it! Anyway, I'd like to change some old (house was built in '54) convectors to some Runtal baseboard...nice clean look.
It would be mixing a few convectors with the baseboard on the same zone. I seem to recall reading somewhere (maybe here) that you shouldn't mix the two. Is that the case or is it OK to use them both? I'm in Massapequa and I have a split level. Any suggestions, comments?
PS...I can't say enough good things about that Ergomax! I remember Dan saying he had one and at the time quite a few people were speaking highly of them. I see Ergomax went out but now Group Thermo I believe it's called has them. Actually mine has both names on it. Thanks!

Brad White_9

The core of that rule

is the thermal mass of the emitters. If both are aluminum fins on copper pipes and both are sized to the heat loss, proceed with confidence.

The problem comes when you mix cast iron with low mass emitters. If the thermostat is in a cast iron-served room, when the 'stat is satsifed the low-mass portions cool off rapidly and will feel colder. (Convection is lost almost immediately and the thermal flux along the wall is gone. Your wall mean radiant temperature plummets and so you feel cold rapidly).

If one were to reverse that and place the thermostat in a fun-tube served room, you would tend to overheat in the CI served rooms.

Runtal can be a mixed bag. It is generally compatible with both fin tube and cast iron but there is a tendency for it to lag CI and emit beyond fin-tube so it falls somewhere in between.

Personally, constant circulation and TRV's evens out most combinations, FWIW.

Brad