Very general question on steam heat.

MaxMercy · October 2020

Reading some recent posts on this site, I've been absolutely fascinated both by the complexity of steam heating systems and the knowledge and skill level of those here who truly understand these beasts and their quirks.

So my question is why anyone would replace a steam boiler when that time comes? It seems from where I'm sitting that other than the logistics of a very complicated refits, it would be almost as easy to replumb for a hot water system. I've done about a dozen house flips over the years and fortunately haven't run into one of these yet, but I've had to do many complete repipes due to freeze split copper, and if I ran into a steam heating system, I think I would replace it.

Other than the fact a steam heat is already installed, is there any advantage to steam heat from a performance, cost, or reliability standpoint?

STEVEusaPA · October 2020

Actually steam is quite simple. All the problems result from poor installations, and people simply not following the instructions and best practices.
All those systems, when first installed were working perfectly fine, and people were very comfortable. It's neglect and poor replacements that create the problems.
Steam systems are practically living, breathing organisms and require simple attention throughout the heating season.

As for as switching it to a water system, this is where huge problems can occur.
First, the radiators may not be the correct type.
Second, you are going from a system operating under 2 psi, and probably not entirely leak free, to completely filling it with water and operating at 12-15 psi. You'll probably find tons of leaks.
There is a beauty for many people of a steam system (working properly of course).

Options...
If you're a flipper, even if you're not, the best options is to have if properly installed/replaced, and properly install/fix all the near boiler piping. Insulate all the piping. Fix the traps (if applicable), fix/replace vents. Make sure all the mains are properly vented. Make sure the radiators are properly pitched. Add AC as a separate system, maybe even a heat pump for AC and shoulder seasons. Side arm or stand alone water heater
---Or---
So if you're not going to do all that, then just rip it all out

But recycle the radiators as they are no longer made and are in demand.
Not a lot of frozen pipes with steam...

Jamie Hall · October 2020

Actually, you're pretty much dead wrong. Steam is a lot simpler than hot water -- and a lot easier to maintain in good working order. For one thing, other than the burner itself, there are no moving parts to speak of which need attention (no pumps, no valves, no expansion tanks...). The only moving parts are in traps and vents, and with a small amount of care will last... a long time (one system I care for they are almost 100 years old, and still just fine, thank you). The only water in a steam system is in the boiler -- so they very seldom freeze, even if someone walks away. Steam is extremely reliable -- if the burner runs, the house heats. Granted, if the system hasn't been maintained, perhaps not evenly, but it will heat. No valves to fail. No pumps to fail. No relay boxes to fail. Steam also is efficient -- a good steam boiler, properly tuned, is the same efficiency as a good hot water, equally properly tuned, except for far more expensive modulating/condensing boilers -- which are more efficient, if and only if they are carefully adjusted (which is not simple) and very well maintained indeed, and the entire system matched to them. Then there's space -- for a given heat output, a steam radiator is only about two thirds the size of a hot water radiator.

So... you gain nothing by thinking about switching to hot water.

ChrisJ · October 2020

I can work with steam, I know close to nothing about hot water.

When you get into those venturi tees and primary secondary pumping etc.....

Not to mention a steam system never needs to be bled and pumps and bladder tanks never need to be replaced. Just throwing that out there.

EBEBRATT-Ed · October 2020

Steam is simpler but only if the right person is working on it.

MaxMercy · October 2020

STEVEusaPA said:

If you're a flipper, even if you're not, the best options is to have if properly installed/replaced, and properly install/fix all the near boiler piping. Insulate all the piping. Fix the traps (if applicable), fix/replace vents. Make sure all the mains are properly vented. Make sure the radiators are properly pitched. ...
Not a lot of frozen pipes with steam...

I've never seen a steam heat setup, much less bought property with a steam boiler. I would say that where I am, steam is pretty uncommon. None of the houses we've looked at had a steam setup. I was just wondering that if we were gutting the house to replace the domestic water copper, would it be prudent to go to hot water.

Jamie Hall said:

The only water in a steam system is in the boiler -- so they very seldom freeze, even if someone walks away. Steam is extremely reliable -- if the burner runs, the house heats.

Excellent point.

Jamie Hall said:
So... you gain nothing by thinking about switching to hot water.

From a flipper view, are home buyers more resistant in general to steam system? I may be in the minority, but I think I would avoid a property with a steam system, maybe due to ignorance which I freely admit, but I wonder if others share my fear as well.

ChrisJ said:

Not to mention a steam system never needs to be bled and pumps and bladder tanks never need to be replaced. .

It seems thought that the homeowner must be an active participant in the steam boiler system. They must be checked for level? They must be "skimmed" several times per season? They must be purged?

So even if a steam system is simpler ( I see that now), it also seems that require a bit more attention throughout the season.

Thanks everyone for the continued education I'm getting here.

Jamie Hall · October 2020

"It seems thought that the homeowner must be an active participant in the steam boiler system. They must be checked for level? They must be "skimmed" several times per season? They must be purged?"

Not really true. The homeowner should be an active participant in any heating system -- doesn't matter what kind. Some are a little more forgiving of neglect (until they break down at oh dark hundred Christmas Eve) than others. However, if one is the more or less typically negligent homeowner, a steam system with automatic water feed will work just as well, if not better, as any other neglected system. So that's item 1. There is no need to check for level after installation, unless the house shifts or work is done on the system. They only need to be skimmed if work has been done on the system -- otherwise they don't need anything. Purging is not necessary more than once every four or five years -- longer if the feed water isn't excessive. Some types of low water cutoffs should be blown down at least a couple of times a month -- but most of them (probe types) don't even need that.

Which is not to say that annual maintenance by a competent professional should not be done. It should. It's not all that different from any other fuel fired system, however.

So no, if you are dealing with the modern plug and play mentality you will be no worse off with steam than any other system.

There is the fear aspect, which I think may be significant: it's old, I don't understand it, therefore I'm scared of it. I'm sorry to say that this does affect a great many people today (and not just for heating systems), and for a flipper may be a something to consider.

On the replacing the copper therefore change the system -- false economy. The cost of ripping out a functioning steam system and installing hot water is large. Very large. It is not an investment which can be recovered, either over time through fuel savings, which are basically non-existent, or through increased sale price of the building.

Danny Scully · October 2020

Any equipment you plan to rely on should be payed attention to, even hot water boilers. I only need to fill my steam boiler 1-2 times a heating season. Additionally, skimming is not needed every season, but rather upon installation of a boiler and or additions made to the system (such as new radiators/piping). Finally, steam systems do not have to be “purged”.

MaxMercy · October 2020

For "level", I meant water level, not plumb, but didn't say it.

Thanks everyone for the education. Fascinating stuff.

dopey27177 · October 2020

As what was said by our steam experts above one pipe steam in many homes is very simple.
1. if all piping is pitched properly condensate (water from steam) flows by gravity, no pumps to move water.
2. Radiator vent valve remove air no bleeding of radiators because they can not become air bound
3. no flooding in the home if a leak develops in a converted steam system where fluid pressures are anywhere from 15 to 20 psig.
4. Radiators in a steam system were calculated to provide heat at a fluid supply temperature of 215 degrees. Hot water heating systems for the most part use a fluid temperature of 180 degrees. At that temperature the radiators may not heat the rooms properly when outside temperatures drop into the single digits or low teens.

Jake

JohnNY · October 2020

I work on steam and hot water systems all day long, especially lately.
I like steam.
I don't love it.
I like it for its simplicity.
I don't love it for its inflexibility.
I like it for its lack of moving parts,
I don't love it for its difficulty to zone.
I like it for its antiquity.
I don't love it for its inability to be energized by a more efficient, modern heat source.
I like it for its ability to deliver a great deal of heat in a given volume of steam.
I don't love it for its large pipe diameters.
I like it for its quiet, non-drying comfort.
I don't love it for its highly limiting reliance on things like pitch and other configuration parameters.
I like it for not being a bunch of water-filled pipes sitting in your walls.
I don't love it for its slow reaction time.

I could go on. Steam is great. So is hot water.
Hot air is absolute crap.

MaxMercy · October 2020

dopey27177 said:

3. no flooding in the home if a leak develops in a converted steam system where fluid pressures are anywhere from 15 to 20 psig.

One thing I would *never* do is convert a steam system to a hot water. If I had it in my head for what ever reason to change an old tired steam system to HW, it would be done with all new copper.

JohnNY said:

I could go on. Steam is great. So is hot water.
Hot air is absolute crap.

That is a GREAT post John!! Thanks.

Very general question on steam heat.

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