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From: chad@anasazi.UUCP (Chad R. Larson)
Newsgroups: net.consumers
Subject: Re: Heat pump/water heater energy conservation
Message-ID: <437@anasazi.UUCP>
Date: Thu, 19-Dec-85 21:04:17 EST
Article-I.D.: anasazi.437
Posted: Thu Dec 19 21:04:17 1985
Date-Received: Sun, 22-Dec-85 00:19:50 EST
References: <237@neurad.UUCP>
Reply-To: chad@anasazi.UUCP (Chad R. Larson)
Organization: Anasazi, Phoenix Az.
Lines: 27

Re: Your hot water heater--
Why would anyone want to heat hot water?

I installed a MagicStat setback controller on my heat pump.  The problem
is that furnaces generally control the blower motor with a separate
thermostatic switch in the plenum.  This means when the wall
thermostat "calls for" heat it only closes the control loop that turns
on the burner.  Some time later the blower kicks in as the plenum
heats.  Heat pumps have a separate control loop to run the blower
directly, for what I surmise are two reasons: 1) The heat is available
immediatly  2) They almost always double as air-conditioners with
different speed blowers.  Anyway- the thermostats that say not for
heat pumps usually mean they are not equipped to deal with the extra
wires to run blowers etc.  In the case of the MagicStat I used there
was on the printed circuit board a trace to cut and jumper to install
that fixed it right up.  I don't know why they didn't document it
unless product liability/support worried them.

On the water heater, timers are commercially available for exactly
what you suggested.  They will help you if your pattern of usage is
such that you don't use hot water for long periods of time each day.
(Everyone gets up and showers/shaves/etc., then goes to work--wash
cloths & cook in evening, then go to bed.)  In that case the timer is
set to turn off the electricity thru the day and during sleeping
hours.  The recovery time on modern heaters makes this operationally
feasable.  If you use hot water throughout the day it doesn't do you
any good.