Steam Baseboard or a Loop??

Petey Pete

I'm putting an addition on my house 25x10.
And I have a 1 pipe steam system already in place.
Been thinking about steam baseboard.
Any suggestions?

Brad White

Steam Baseboard

in one-pipe steam has a limited "travel distance", not to mention, if Cu-Al fin tube entirely different thermal properties. If you tie in Cu-Al baseboard to an otherwise cast iron system you will suffer with a distinctive coolness in that fin tube heated room while the cast iron areas will be just fine.

If you use CI baseboard the lengths are limited to about 9 feet IIRC.

Extending one-pipe steam is an art too.

Rather, I would make a HW loop from below the waterline. See the Heating Q&A above for several ways to use condensate for heating separate zones. You will be much happier.

Steamhead (in transit)

Where is the boiler

in relation to the addition? If it's close you could just run a new steam main out there. Cast-iron baseboard would have to be connected two-pipe unless the lengths are under 6 feet or so, but would still be my choice since its thermal behavior is the same as cast-iron radiators.

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Christian Egli_2

What about looking into what you're doing for hot water

I have no idea how these dimensions compare to the existent structure, but you shouldn't forget to check your steam boiler capacity. This is a must.

Ideally, I would prefer keeping everything steam, just for love and for consistency.

But...

I find beauty in redundancy. I don't know what your addition is, and it might be excellent to have a heating and cooling system that is separate from the rest of the home. Why heat your bedrooms to the same cozy temperature you want your new den at?

A completely new system just for the addition sounds real nice. And surely, one of them at least won't break down on the coldest night.

A combined AC/heat pump might work (providing you don't live somewhere too cold)

Better yet, a brand new separate hot water system. Combine this with a new domestic hot water indirect tank and instantaneous heater (but keep drinking water separate from radiator water) and you'll find new efficiencies in your hot water production, and heat you can dial in separately from the whole house. Ideal.

Steam boilers are always desirable as is, while standard domestic hot water production is always due an upgrade. You can't loose going this route.