Heating Help

Why hot water and not steam?

I'm just curious why many modern homes (1940s and up) use hot water heat instead of steam.

I've seen quite a few posts saying steam heat when configured correctly is more efficient than forced air and even hot water.  If this is so, why isn't steam more popular or even existent at all in newer homes?

I know why forced air is popular, its CHEAP to install.  But hot water isn't any cheaper to install than steam, is it?

What are the pros and cons,  steam vs hot water?

As many know, I'm 100% for steam,  I'm simply trying to expand my knowledge and understand the whole picture.

cost

Threaded steel pipe is a lot more expensive to buy and even more expensive to install. Builders are VERY sensitive to costs.

Bob

pretty much

just cost...water could use smaller copper pipes..and copper was much cheaper back then.

One big advantage of steam

is that it won't freeze up in an extended fuel or power failure like hot-water can. Except for some pipes in the basement, and the boiler itself, the system drains dry when it shuts off.

But steam does not tolerate poor workmanship. And builders in general don't care about workmanship as long as they get their money.

I Love Steam

...and I know how wonderfully steam can work.

But by varying the temperature of the water, a well designed hot water heating can do the job more efficiently than steam.   Water is also easier to zone, and much easier and cheaper to buy and install.

The lower the temperature of the heating medium, the lower the standby losses. 

Which is why steam heating is outlawed in much of Europe,and why many municipalities will not permit the installation of new steam heating systems here in the USA.

Steam outdoor reset.....

steam temperature can and has long been varied in temperature. 
Steam is as easy to zone as hot water when considering how it is done in Europe (TRVS). 
 Standby losses can be very low with steam since it has very little mass compared to water  (1lb of steam carries the same amount of heat as 50 lbs of water in typical systems, 100 lbs of water in typical radiant floor systems).    
Steam can use the same size copper pipes and much smaller radiation than hot water.  I
It also can respond nearly instantly, like forced air, but still provide very stable comfort under steady loads. 
Steam also uses a fraction of the amount of eletricity as hot water since no pumps are necessary for circulation, making it much more efficient in the use of our least efficient energy source.
Steam is easier to  make repairs to the system because little or no water needs to be drained. 
Like Steamhead said, no freezing issues.

Ah, But Gerry has addressed the cost issue..

with his minitube system.  Small copper pipes, much smaller radiation than hot water.  I believe the biggest issue is apathy or belief that steam is not in the future by boiler manufacturer's.  There is zero marketing on thier part, yet nearly all of them have good people that know that steam can't be matched in performance in most ways.  
 I've begun marketing steam as a high efficiency and comfort alternative in the past few months and already have 3 homeowners that want to convert to steam from forced air and a number asking about converting from water to steam. 
 As Steamhead said, (with no disrespect for those here that truly know the hot water trade), steam requires better training to have it work properly, where hot water is much more forgivng of incompetence.

1. The manufacturers, AND WE, need to begin pressing the Dept of Energy to change their testing methods that inherently give greatly inflated efficiency numbers to forced air heating and A/c and to a lesser extent hot water heating equipment and inherently undervalued numbers to steam equipment.  Thier testing is not only flawed, but ignores system dynamics and how they interact with buildings and people. 

help?

Is there anything I and other home owners on the wall can do to help the future of steam?

Hot water circulator and small copper piping

In addition to all that's been said, I think the hot water circulator and the ability to use small copper piping that didn't have to hang low from the ceiling that did it.  We can't ignore the fact that the advent of forced air (instead of gravity) was changing everything and was the cost standard of the post war building boom.  And this happened before the widespread use of air conditioning.  The "new and improved" hot water was the only wet heat that stood a chance from a 1st cost perspective as compared to the "new and improved" forced air system.  The home I live in has early forced air (1939) yet there are a few (very few) houses of the same type and vintage in this development that had the optional Steam Heat Upgrade. 

But steam was viewed in that transitional era as being the system with the big expensive steel hanging (and banging?) pipes that screwed up plans for the "new and improved" knotty pine basement rec room.

No one wanted the pipes and no one wanted to twist that pipe.  Unfortunately, the Iron Fireman SelecTemp copper tube steam heating system came too late in the '50's as I think the tide had already turned.  As boilerpro pointed out, the minitube system (like Gerry's) is actually easier to install than HW, but I think SelecTemp's proprietary steam turbine driven unit heaters priced them right back out of the ballpark.

But steam got bumped out of the market so long before condensing technology existed that I doubt "efficiency" was what pushed it out.  When I was growing up, my dad the architect always viewed steam heating as a very efficient system in its day. 

It was cost and prevailing view of how it had to be piped (BIG) that did it in, IMO.
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Regarding heat loss in pipes, I've often wondered if anyone takes into account that the heat loss from steam lines is primarily from the main and runouts, but not the return; and that the supply and return on a hot water system are nearly the same temperature with similar heat losses.  This is, of course, because hot water releases so very little heat into the room (including the radiator) for the amount of mass circulated as compared to steam.  Just askin'

I've never bought into the whole idea that steam is so difficult to control.  If you use TRV.s or, like in the old days, pneumatic thermostats, I see no problem.  I guess I've been privileged to have been exposed to steam heating systems both large and small that were working as designed.  Believe it or not, I never heard a steam system "clank" until I started working in the steam biz.  The bigger systems at my school all had room thermostats and modulating burners on the boilers.

And as Steamhead said, the steam heating systems can tolerate freezing. I know that my school's system would shut down towards the end of the school day.  They had those classroom ventilators, and I'm told that that stuff regularly went below freezing over weekends and Christmas break.  

In the rustbelt here, the number of foreclosures in recent years has exposed this achilles heel of hot water heating.   I have witnessed the demise of a disturbing number of hot water systems due to freezing.  Many times the Bank's winterizing service showed up after the damage was done.  So far the steam systems have survived.

Ed, have you actually run into

"municipalities (that) will not permit the installation of new steam heating systems here in the USA"?

New York

The New York State Energy Code requires all new home installations to have Annual Heating Efficiency ratings of 90% or better.   There is no exception for steam boilers in new construction. 

I doubt a plan examiner would know the difference if I submitted plans for steam as long as I included the required heat loss calculations.

Code enforcers usually (but not always) want a print-out from a combustion analyzer showing no less than 90% when they sign off on the job.  On existing systems, steam boilers are exempt, but even a new hot water boiler in an existing home must meet this requirement.

I don't see how we could install a new steam system in New York and get the 90% sign-off. 

I like steam but water is cheaper to install new and

water is more efficient then steam heat. If the building already has a steam system the efficiency savings do NOT out way the cost and trouble with converting to forced hot water if the majority of the system is still in good working order. Steam makes sense if you already have it but not as a new system. This is all depending on equal quality of workmanship and attention to details for both systems. The Fire man system could turn this on it's head, but only time will tell.