Heating Help

Steam versus Hot Air

To my dismay, my church is considering replacing our existing steam radiator with forced hot air. I'm familiar with many of the fundamental arguments against doing this, but I'm intrigued by something I read here on the Wall in regards to churches in particular.
I read here (http://www.heatinghelp.com/forum-thread/79128/Heat-loss-for-churches) that in such cases, steam systems were often greatly undersized compared to heatloss. The thought was that the radiators could keep things at ground level (like pews and such) nice and warm without necessarily heating the very top of the church. From my own crude estimates of heatloss, this seems to be the case- the connected load (about 1000 sq ft EDR) is substantially lower than heatloss. This is a high ceilinged (75'?) stone church with essentially no roof insulation. The original tongue and groove roof decking is visible from inside the church.
Being that a hot air system could not help but heat the entire envelop, am I correct to assume that in a case like this hot air could be significantly more expensive to operate? Could heating up the air against our uninsulated (cold!) roof/ceiling have deleterious effects as well (condensation? rot?)?
Any thoughts on this subject would be appreciated.
Thanks,
Patrick

Your fears are well grounded

it would definitely cost more to run, for the reasons you mentioned as well as the lower comfort level making people want to turn up the thermostat. Not sure about the condensation issue but I would think all the humidity from all those people has to go somewhere. Also, if you have a pipe organ, check with whoever maintains it to see how forced-air would affect it. 

radiant

Is AC part of their reasoning?  If it isn't then forced air is an idiotic choice for a space like a church, especially a stone church.  The costs will be higher and the comfort will be lower.

However, if AC is one of their reasons, it is more difficult.  A better answer would be ductless heat pumps installed at strategic locations in addition to the heat.  Honestly, if they really need a new system and if possible, an even better answer would be be a radiant slab for both heating and cooling.  It would be a more consistent radiant heat than the radiators for greater comfort.  Depending on your climate, you might need to deal with humidity and condensation in the summer.  But that is a doable thing.

Pipe organ

Steamhead's remark on the pipe organ -- if you have one -- are right on the money (besides the sundry other things I get involved in, I'm the assistant Minister of Music for my local church, and a lifelong organist).  Pipe organs are incredibly fussy about both temperature and humidity changes.  They don't mind (too much) temperature changes, if they are slow.  They go out of tune dismayingly fast if the temperature changes are quick.  What they really don't like, though, is dry air, particularly warm dry air when the instrument is cool or cold.  They can actually become unplayable, if the condition is severe.

So think about that one.

And there's nothing worse to hear

than an organ that's out of tune!

Fussy pipe organs...

If they have electropneumatic action (usual in most organs in USA), they hate dust as well. Each valve under the pipes is like a SPST relay, where what is being switched is air. The moving element is a thin disk of magnetic metal crimped around a soft bit of cardboard or similar material. In the organ-building business, these are called magnets. Devised by Robert Hope-Jones. The disk is quite small. But if dust gets in there, it will not close and so pipes will sound when that is not desired.

But just as steam systems should not be replace by forced air or even hot water, so genuine pipe organs should be restored, if necessary, not replaced by electronic ones.

What I expected

Thanks all for the supporting views- it's just as I thought. I suppose that means you're "preaching to the choir?" I think AC may be part of the draw, though it seems unrealistic to me.
It's a classic situation- a long neglected one pipe steam system with high gas bills. At this point, installing hot air might actually result in gas savings, but de-kniuckleheading the system and adding a new boiler would be far better!
Anyone out there with more evidence, anecdotal or otherwise that the switch to hot air would not be a good one?
I'll keep you posted.
Thanks all,
Patrick

Found some more

check these out:

http://oikos.com/esb/44/forcedair.html

http://oikos.com/esb/28/duct_losses.html

Don't hesitate to get in touch if you need a consultant.

Awesome!

These are terrific, thanks!
Patrick

the noise factor

why not arrange a demonstration of the difference in noise between the 2 systems: at some meeting where the deciding parties are, plug in first an electric hair dryer, and then an en electric kettle. ask them which would be more objectionable.
the new mini-split a/c's are quite quiet.--nbc

Here's what happened

at a church where they did just what you describe due to getting air conditioning and the heat package was "almost free" in the scheme of the total budget. [I found out about it since they had 55 radiators for sale] As you surmised, lacking a radiant heat component at floor level, the choir level would rise to 85 degrees to keep the floor level at 65 degrees. In desperation, they installed tiny ceiling fans waaaay up at the ceiling which, of course, were of psychological effect only.

The full effect was not known until it was too late. The next season, they had to install electric baseboard heating throughout the offices and restrooms, and other utility areas because they were inadequately heated with the new system. In talking to an old timer there who kept up the steam heating system, it became clear that the comfort level dropped substantially and that the increase in electricity consumption more than offset any savings in natural gas.

They should have kept (and optimized) the steam heating system they already owned and kept the forced air for air conditioning only. Best of both worlds.

and another thing:

Tuning up the steam system is just the beginning of the process. Check out the Interfaith Coalition on Energy.

They have extremely effective advice as to how to properly and efficiently conserve energy in sacred structures. Good stuff there.

I'll second that

especially since they mention this site on their links page!

ICE

I'll third them. I worked with them a couple of times when I was in CA.