New to steam heat and I know nothing
November 29, 2019 9:30 PM   Subscribe

I just bought a house with steam radiator heat. I've never had this kind of heating system in my life, and I don't know the first thing about it. Is there anything I should know about maintenance or any tips for keeping it running efficiently?

Not only am I new to radiator heat, but I am also new to home-ownership. Please explain it to me like I was five. Is steam heat cheaper than gas? Should I think about replacing it for a furnace?
posted by ambulocetus to Home & Garden (12 answers total) 7 users marked this as a favorite
Best answer: The first and last things about it can be found in the excellent "We Got Steam Heat!: A Homeowner's Guide to Peaceful Coexistence". It won't necessarily answer all your how-tos, but it does a great job of demystifying the inner workings of the system. I bought it in a similar head-scratching moment — what do I make of that sound? what does this behavior mean? valves open, closed?? The book is great.
posted by wemayfreeze at 9:42 PM on November 29, 2019 [6 favorites]

We have steam heat. It’s inefficient, but at least in our setup, replacing with forced air would be quite expensive because we have none of the requisite ductwork. If you have what they call a two-pipe system it’s possible you could replace the steam boiler with a hot water boiler, and I believe those are more efficient (we have a one-pipe system, so that’s the beginning and end of my knowledge here).

For maintenance, we get ours inspected once a year. We just replaced the boiler this year actually (the one we got rid of was older than I am) and the project ran around $7K I think.

N.B. the energy source that you use to produce your heat and the type of device that produces it are separate things. We have a gas-powered boiler.
posted by eirias at 12:58 AM on November 30, 2019 [1 favorite]

Just to address the side issue: yes modern water boilers are insanely efficient, we just got a tankless condensing boiler that’s over 98% efficient at turning gas BTUs into house BTUs, so that could save you a lot of money in the long run, worth getting someone one to assess if your house is a good candidate. This would in principle cost much less to install than a forced air conversion and also cost less to use.
posted by SaltySalticid at 4:40 AM on November 30, 2019 [1 favorite]

I grew up in a large, weird house that had steam heat. The original boiler was coal fired, but I'm really sure you're not using that filthy stuff. It got replaced with a gas boiler when I was 10 or so. Both systems got that house so hot you basically controlled the heat by cracking windows. A guy came once a year to flush the system. Other than paying the gas bill, there was nothing to do.
posted by james33 at 5:30 AM on November 30, 2019

Best answer: These systems are extremely simple- it's basically a big burner under a big cast iron pot.

There are no condensing boilers for steam heat, because the physics doesn't work out. The best you can do is about 85% efficient.

It is probably a good idea to have the guy to come out once a year to make sure things are in good shape. Our guy recommends also draining the boiler once a month or so when it is in use, which reduces the amount of sediment that accumulates. We are not terribly good about doing this, the world continues to go round.

You should see if you can figure out whether the pipes are insulated with asbestos or fiberglass, and then consider remediating.

These couple videos are pretty good to go over issues with radiators: How to Maintain a Steam Radiator | How to quiet a banging radiator
posted by rockindata at 5:56 AM on November 30, 2019 [4 favorites]

Best answer: I like steam heat, but I'm also an engineer. And I don't have steam heat anymore, because I live in the South where all the houses are ducted for forced air heat and AC. I didn't buy the steam heat book, but I should have; it would've made things a lot more straightforward.

So, there are a few different ways to get heat from the furnace to you. Steam heat, you run pipes, typically slightly uphill when they're horizontal, from the basement to the rooms, and have radiators in each room. Then you try to balance it so they all heat up about the same.

A radiator is a big cast-iron tube with fins, with an inlet on one end, and a heat-sensitive vent on the other end. Under normal circumstances, it's empty and open to the environment. When steam comes in, it gradually goes through the radiator (condensing on the walls, and running downhill back to the boiler), until it gets to the end and heats up the vent, and the vent shuts off. Now this radiator is pretty much done; no more steam is coming in until it cools off, but if there are other radiators, the steam will go there too.

Hot water, you have to run two pipes, one to each end of the radiator, but maybe the pipes are smaller.

Forced air, you need big honkin' ducts running through the walls from the basement or the attic or wherever, but at least you can also run cool air through them in the summer. If you do not already have big honkin' ducts, then switching to forced air for heat or cool is...non-trivial.

In my experience, the things you need to watch out for are:
1. Either open the valves (the big handle things at the start of the radiator) all the way or close them all the way. Partway is trouble.
2. Make sure the vents (the little silver things at the end of the radiator) shut off. If they keep spitting steam indefinitely, it's probably time to replace them. You can usually hear them shut off, they make a clicking sound.
3. The radiators are supposed to all heat up at about the same time. This isn't always possible. But they sell different sizes of vents, so you can let some radiators heat up faster, and some heat up slower, so you can balance it out.
4. Make sure your thermostat works. I tried a dial thermostat, but it required power from my old janky wiring because they don't have mercury switches anymore and the boiler kept cycling on and off. Eventually I had to switch to one with a battery so it would communicate right. There is a thermostat setting for steam heat, so it'll use longer on/off cycles.
5. Water level should be between the little lines on the boiler check glass (open the little knob valves, check, close), and pressure should be low.
6. Do you have gas or heating oil? If you have heating oil, you need to know, because at some point some guy in a truck is going to have to come pump more heating oil into your tank for you to continue to have heat. If you have gas, then a handy pipe already runs to your house. You might also have 1-2 old tanks for previous heat sources that are in the basement that are too big to get back out of the basement.
7. Know where the pilot is and how to start it.
8. You can experiment with a fan blowing air over the radiator, or some sort of reflective radiation backing, if you want. Not sure it works in a way that's meaningful.
posted by Huffy Puffy at 6:16 AM on November 30, 2019 [3 favorites]

It is probably a good idea to have the guy to come out once a year to make sure things are in good shape. Our guy recommends also draining the boiler once a month or so when it is in use, which reduces the amount of sediment that accumulates. We are not terribly good about doing this, the world continues to go round.

The boiler in our rental also needs topping up with additional water on about a monthly basis while in use. It's theoretically a closed system, but there will always be losses somewhere or other. I think our guy recommended we drain the boiler at the same time, which would make sense, but there's no drain in the basement and I honestly can't be bothered to empty the bucket. So I don't bother unless there's obvious sediment visible in the fill meter. Not the best way to handle things, but indeed the world continues to go round.
posted by tobascodagama at 8:16 AM on November 30, 2019

Best answer: Steam heat is so great! Absolutely read the book linked in the first comment, and the website of the guy who wrote it: Dan Holohan. He has a bunch of other books and videos. You can't help but fall in love with it a little.

Also - about water refills - the boiler shouldn't need much refilling or draining. Most systems have an auto-refill for safety, but if your system is refilling often, that can be a sign that something's wrong - we didn't realize this until it was too late and the boiler had cracked, but it's worth being aware of. The boiler probably says somewhere, something like "if this unit requires more than x amount of water added per month [or year] please have it serviced."

I'd look around and see if there's a company on that specializes in steam in your area, or ask the previous owners who they had service it - in many places steam is rare now and ideally you want to find someone who's experienced with it for your service person.
posted by LobsterMitten at 8:54 AM on November 30, 2019 [4 favorites]

Chicago is steam heat territory so I’ve lived in many apartments heated with steam. Currently we own our unit but the association pays for radiator and boiler maintenance so we don’t have to do anything.

Having a well maintained system has made me appreciate how nice steam heat can be. Ours does not leak, does not clang or clank at all, and the radiators don’t hiss steam because the valves work properly. If yours does any of those things, regular maintenance can help.
posted by mai at 11:39 AM on November 30, 2019

If a radiator is clanging, it has water in it. Put something underneath to raise the radiator at the end that's not connected to the steam pipe.
posted by wryly at 2:57 PM on November 30, 2019 [1 favorite]

Best answer: Huffy Puffy gives sound advice above, but be aware that his first three points only apply to one-pipe steam systems. The other kind of system is two-pipe. If your radiators have a pipe with a valve on one side and another pipe without a valve on the other side, you have two-pipe steam.

If you have a two-pipe system, you can use the radiator valve for throttling purposes. My upstairs radiators are grossly oversized, so I keep them opened a 3/4 turn and that’s about perfect. Two pipe systems don’t have vents—they have steam traps on the outlet side of the radiator instead. These have “speeds” just like steam vents and can be swapped to help balance the system. They also wear out like vents and need to be replaced from time to time.

Please do get Dan Holohan’s books mentioned above. I started with We Got Stream Heat and moved on to The Lost Art of Steam Heating. The message board at is an invaluable resource as well.

Steam, when working well, is the most comfortable form of heating. It will never be the most efficient, but it’s something I really love about our old home. Good luck!
posted by TrialByMedia at 1:01 PM on December 1, 2019 [3 favorites]

Response by poster: Thanks, folks! I've already learned a lot, but I did order the book, too. Winter's just starting, but I think I'm going to like steam heat. Of course that depends on how big my utility bill gets ;)
posted by ambulocetus at 11:11 AM on December 3, 2019

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