replacing radiators

Pat McEnroe

We love our two pipe steam system, but the boiler leaks and don't like the look of radiators. Our two floor 2400 sq ft house has a heat loss of 135,000 btu/hr. We'll remodel about 800 sq ft of this, so I thought I'd put in radiant floor heating, but best case I'd have 32,000 BTU output from this. We have a spacepak heatpump system, and could install a hydronic coil for supplemental heat (at 10 gpm and 180 deg input, the output would be 120,000 BTU's and all the outlets are in the ceilings on both floors so no issue with too hot air from a safety standpoint).

Suggestions?

Steamhead (in transit)

Keep the steam

and get the radiators stripped and repainted. It's amazing how much better they look after that is done. Your system is probably Vapor, which was the Cadillac of heating in its day and is still one of the best out there.

For the section that will be remodeled, you can get radiators with a more modern appearance. Check out www.steamradiators.com .

If you can wait that long, the new Burnham Mega-Steam boiler will be out shortly. It is said to be the ultimate in steam boiler efficiency (so far).

You already know the limits of radiant in your house, and the mini-duct system will never give the level of winter comfort that the steam will.

You already have the best. Keep the steam.

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Pat McEnroe

Thanks for your reply.

Of course you correct about the comfort of steam, and I am inclined to agree with you regarding repainting the radiators. However, no lesser authority than my wife's mother has agreed with my wife that radiators, regardless of how well they are painted, are ugly.

One question I have - I did my heat loss calcs based on an outdoor air temp of 1 deg F. Most of the time the temperature is well above this in Cincinnati. Would my plan to use radiant in some of the house, with the heat pump/hydronic coil provide nice heat when it is say 30 or 40 degrees outside, then not so nice when it gets really cold?

--pat

Steamhead (in transit)

You can answer that question

by playing around with outside temps in the calc program until you come up with a heat loss similar to the available BTUs mentioned earlier. Then you know how low you can go with that setup. But you'll still need the steam when it gets colder.

I've seen some radiators that were stripped, painted and then the raised surfaces in the iron were all "detailed" in a different color. That looked really sharp!

And- your mother-in-law doesn't live in your house, right?

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Pat McEnroe

Thanks, I'll give that a shot.

No, she doesn't live with us, but I learned a long time ago that I can't dig myself out of a hole with a shovel!

I really do have one more option - I only really need to remove the steam radiators from the areas I'm renovating - the others have (very ugly in my opion) covers that are acceptable. So here's the solution if it will work. Upgrade the boiler and install a stand-alone system for the radiant. The only issue would be no supplemental heat for the renovated areas. Those renovated areas I could install furring strips and insulate the walls, so maybe the heat loss would not be so bad and as long as I kept doors open heat from the rest of the house would migrate....what do you think?

Steamhead (in transit)

If you use the shovel

to dig steps into the side of the hole, you'll get out fine.

The radiant setup you describe would be a kludge at best, since it probably wouldn't work well except in milder weather. Whatever you install has to work well, otherwise you and your family will be miserably cold.

Have you checked out www.steamradiators.com? These really aren't your grandfather's radiators. If you go this way, you can size them to the current heat loss which is probably less than when the house was first built. This would result in smaller radiators.

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Pat McEnroe

Thank you for you help Steamhead, but I won't be adding new radiators, regardless of how nice they are:) I did take your advice and I relooked at my calcuations. I've figured that I can make a substantial reduction in heat loss through insulation as I mentioned, as well as through insulation of the attic and adding storm windows. My real hobby is woodworking, so I'm sure I can build some nice storm windows. I will keep the existing radiators, and with my calculations now I can take care of the supplemental heat required beyond radiant through some family acceptable baseboards.

No scorched air, comfortable steam for most of the house, comfortable floors in the renovated areas, and I'm done. Now, one more question - is there a single boiler solution that will allow me to do the steam as well as the circulating water (I assume a tankless coil connected to a storage tank)?

Pat McEnroe

Forgot to mention - good idea on the use of a shovel to get out of a hole - never thought of that!

Steamhead (in transit)

You could do it that way

but depending on the load it might not be economical to fire a large steam boiler for a small radiant zone. The tank would, however, provide a buffer which would reduce short-cycling.

You might want to think about using a separate hot-water boiler for the radiant though- and also to drive an indirect heater for your hot faucet water. This would make very good use of the second boiler's capacity all thru the year. Then you could use a smaller steamer.

"Steamhead"

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Pat McEnroe

Sounds like the right solution - two systems, with the hot water system for radiant and domestic. From what I've read, it is important to keep the radiant separate from the domestic - using a heat exchanger. I can wait a bit before replacing the steam boiler, so I'll see what this new boiler you mentioned in your first post is all about.

Steamhead (in transit)

The indirect heater

will provide the necessary separation of domestic and heat system water. It has a built-in heat exchanger which may be a coil or may be a tank-in-tank arrangement (my personal favorite). However, some local codes require two separations- in that case you'd use a flat-plate heat exchanger between boiler and indirect.

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