[VAC] Re: Radiant flooring

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

Solar for water preheat seems to work well.

Active solar for house heat doesn't in my experience. I've concluded
that the right amount of windows is more effective than any active
system. And I was surprised to find that Pella's coated thermopanes are
less effective for heating than their plain glass thermopanes. Turns out
that the coating reduces solar insolation more than it reduces heat
losses.

Using the fresh and gray water tanks as storage element might be of
minor benefit. Though such a system might need a temperature
transformer, called a heat pump to make the stored heat useful. There
would be the chance of a bit of heat recovery from waste hot water from
sinks and shower. Generally the heat is definitely there, but too low a
temperature to be useful without using a heat pump to change its
temperature.

All refrigeration systems (including mechanical dehumidifiers) are
actually heat pumps. I don't yet have one, but an air to water heat pump
can heat hot water a bit more efficiently than resistance heaters. In my
house design I plan exhaust vent heat recovery with one, using the hot
water heater/boiler as the heat sink.

Gerald J.