Forced air vs. water

Post Reply | Watch this Post

I believe it's to a large extent regional a thing.
Force air is easier and cheaper to install so it is
tending to take over. There is a downside to FA which
is largely ignored (at least until serious problems
occur). The bulk of FA systems employ a central air
return i.e. supply ducts run to each room but return
air is through a single grate in a common area. That's
fine until bedroom doors are closed; then suddenly a
large amount of air can't get back to the return. the
effect is that the bedroom pressurizes, while the rest
common area depressurizes. Close all the bedroom doors
and it's easy to get enough depressurization to cause
backdrafting on atmospheric vented combustion appliances
eg. gas water heaters, fireplaces, and the furnace
itself, not to mention pulling air from attached
garages, and soil gasses from crawlspaces. The moral
is to be aware of how your house works. FA can work
fine if properly installed i.e. adequate combustion
air supply, tightly sealed ducts, and either individual
room air returns, transfer ducts, or pressure relief
vents.