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Posted by steve on December 02, 2007 at 15:24:39:
In Reply to: Re: Convector and recessed radiator EDR calc posted by HeatPro on December 02, 2007 at 13:15:22:
So to go to condensing from steam I would either need half the heat I currently have or larger radiators.
Without insulation (just stucco and plaster) and new windows (I have storms), what sort of typical payback period do you see on hot water and condensing hot water? Do you have any idea as to the ballpark cost (at least the order of magnitude)? The house is ~3100 sf, 13 radiators, and 6 convectors.
If you run both pex through he current pipes won't the return water cool the hot water or is insignificant? Generally, how large does the single pipe have to be for this to work? Can such a system be zoned?
What type of boiler is used? Stainless?
: : How does one run the supply and return? Can you run both in pex through the existing piping? Or do you have to add another set of lines?
: ++ Depends on whether the original lines are large enough to pull both or not, at worst you'd have to run another line up the same way the originals were, or pull them like snaking electrical wire.
: : Have you encountered a problem where the home just isn't warm enough after a hot water conversion?
: ++ Not after I set them up; often when the newbie installer left the high limit too low.
: : Is it ever more costly to heat with hot water than steam?
: ++ Steam heat is the big waster of energy, Hot water can be modulated to save energy, that's why it is done to convert to hot water.
: : What is done differently for condensing hot water versus ordinary hot water.
: ++ You need twice as much 130F radiation surface for condensing water temperatures as with 'ordinary' 180F hot water temperatures. Cast iron and steel boilers can not be run at 130F max for long without rusting.