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Scrap my cast iron steam radiators?

Hi all,

I recently purchased my first home which was built in the early 1940's. It has steam heat with cast iron radiators. The boiler is on it's last legs and needs replacing. Trouble is, I don't know what to replace it with.My plumber is advocating for a hot water system with baseboard radiators. I've been doing some research and the concensus seems to be that cast iron radiators can't be beat.So what do I do? Install a new steam boiler and stay with steam? Go hot water with the less efficient baseboard?
Can I convert my existing cast iron radiators to hot water? I don't want to go over $10,000.
Any info would be greatly appreciated.
Thank you.

Re: Scrap my cast iron steam radiators?


I would tend to agree with your plumber and have forced hot water baseboard installed.

It's not likely the steam rads can be converted to forced hot water, as they are usually rusted shut & are often "one pipe" systems that would require expensive modification before they could be used for FHW, if they could be used at all.

Baseboard is not inherently less efficient than cast iron, but the heat doesn't stay in the baseboard as long as the rads, & the cast iron has the ability to retain the heat for an hour or more, emitting radiant as well as convective heat; many people find this more comfortable on cold winter days.

Baseboard is much easier to install & service, as well as modify if a new zone is needed or other modifications become necessary.

The installer should first do a Manual J heat loss calculation for each room to determine how many feet of baseboard are needed for each room so that the system heats each room in the building properly.

Get several estimates from such sources as in the Yellow Pages: "heating contractors" or "fuel oil dealers"---the price & choice of equipment will vary widely with each quote & estimate you get.

If At All Possible

Keep the rads. They can be flushed, inspected and possibly converted to hot water. I the gentleman above stated. First step is a room by room heat loss. Then an inspection of the exisiting piping and rads to determine whether they can be kept or not.

Is this a gas or oil boiler? If gas and a modulating condensing boiler sized based on the heat loss is in the budget that is the way to go. If oil, you want to look at 3-pass style boilers such as the Viessmann Vitrond 100, Burnham MPO etc.

The reason being is that these types of boiler can handle low return water temperatures that allow you to reset the boiler. This means that your boiler can fluctuate water temp based on what is going outside. General rule of thumb is for every 3 degrees you can run less than 180 degree water you save 1 percent of fuel. See, you only need your design water temp on the coldest day of the year to overcome the heat loss. Not when it's 20 or 30 degrees out.

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