# Steam heat vs Hot water heat



## K2eoj (Aug 14, 2005)

I own a stream system and a hot water system and know quite a bit about both systems but am not an expert. But I'll tell you what i know until someone else shows up. 

HW needs about 3x the radiation as steam because steam is hotter. 
I personally question the 3x rule because a steam radiator cools down very fast when the boiler stops making steam. Hot water stays hot for a long time and usually keeps recirculating.

Regardless being under radiated is inefficient and makes the system work harded. Too much radiation is the way to go in my opinion.

A boiler is a boiler is a boiler. That is what I'm told by my heat guy. He says he can change the hardware on my steam boiler and the radiation, and make it a HW system. I've heard of guys using water heaters for boilers. 

That's everything I know.


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## mdshunk (Dec 4, 2005)

Wow... you're really mixing terms in your first post, and I'm sure that you don't even realize it. 

A radiator is the cast iron things, and a convector is the fin stuff that you run along the baseboard. 

You can really, really, really, really, really screw up a system if you arbitrarily add or delete radiation and change the size of the radiation in a steam system. The size of the installed radiation has to damn near equal the steam capacity of the boiler in order to have all the radiators filled with steam and to recondense the steam to water. I wouldn't go fooling around with changing the radiation to a different style unless you've had a qualified steam heating contractor or heating engineer calculate the EDR required for each room and in total. You'll be in a world of hurt if you do this on your own arbitrarily without calculating exactly how much of what size of the new type of radiation you propose you need and where. 

You can very easily convert a steam boiler to a hot water furnace by the elimination of a few controls. Unfortuneately for you, you have a one pipe system, so you'll also have to run more pipework. A hot water system requires much, much more convection surface area when compared with steam radiation.

I don't want to discourage this project. I only want to encourage you to seek the assistance of a steam heating contractor or a heating engineer to look the place over, do the calculations, and spec the radiation for you. It's nowhere as simple as hooking something that's prettier than the old one to the end of the pipe.

Perhaps you will consider just having a sandblast contractor blast the existing radiators to bare metal and repaint them? Many turn of the century buildings still have their original radiation installed, even though the building has been rennovated many times. Sometimes it's best just to leave a good thing alone.


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## helpless handyman (Jul 6, 2006)

Hi, I went to this place that sell radiators and heat elements and they go by size room and how many windows are in each room. I wasn't going to just purchase radiators on my own. Also, if you had steam pipes that were 75+ years old, should they be changed? I have my walls open now and was wondering this is the time to change them and at the same time I can move the pipe that is running in the middle of my basement ceiling. Thanks so much.


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## K2eoj (Aug 14, 2005)

> Also, if you had steam pipes that were 75+ years old, should they be changed?


Steam pipe does not corrode and block up like old galvanized water pipe. Since the water is reused there is something about less O2 entering in the system. 

Mine are 75 years old with no blockage at all.


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## helpless handyman (Jul 6, 2006)

Thanks, I guess they'll stay!!!


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