In general, leave it run. One would need the electricity cost in your
area, the balance point of your home and the specs on your heat pump
to determine which is more cost effective to run and when.
Its a heat pump and they run a lot in cold weather. If you dont like
it, turn it off and turn the back up electric heat on. Then watch the
electric meter spin off the wall.
Theory? You dont know how to figure balance point of a home? If you
would read between the lines you just might figure out that the poster
is complaining that the heat pumps runs almost 24/7 and is wondering
if it should be turned to "em ht" and skip the condensing unit
operation of her system. With electric as your back up, its still more
efficient to run the heat pump than to just turn it off and run on
electric resistance, even down to 0 degrees. Look at the performance
specs of the unit and you might be able to understand.
Just so you know, I have a gas 2 stg var spd gas furnace with a 14
SEER heat pump, fossil fuel kit and H/W Vision Pro stat. I fuck with
it all the time and I know what Im talking about. Would you like to
see my utility bills before and after my heat pump addition, Joseph?
Theory? God Damn idiot.
Look at the cop specs on just about any heat pump--IIRC they drop down to
about 2 when the outside temps get into the tens and below......so, unless
the unit is defrosting 50% of the time, it is still more economical to
operate as compared to electric heat strips.
Your total heat output drops too, though--but under this condition, so does
the electrical current drawn by the compressor.
What I do here is I use a water source heat pump unit as a auxillary to our
main air source unit--it draws some well water during the occasional cold
snap we get in our area.....but as it only operates as auxillary, there isnt
a huge or constant demand on the well--and with the ~50 degree well water,
it maintains full heat output at a cop just a tad above 3
And in the summer, I can change the water source over so that it cools the
house at the same time its heating the swimming pool.
It will decide for you. When it can not provide enough total heat the
resistance heat will kick in. I would assume, which is always a bad thing to
do, any well designed system would shut down the heat pump part when the
temperature was so low as to be come less than 100% efficient. Sorry I
really don't know if they do or not. If not, they need better engineers.
Only if its a programmable ( smart ) thermostat will it will fire the aux
heat strips automatically, otherwise this same terminal on the air handler
will also ( usually ) be tied in with a signal from the heat pump condensor
in order to activate the aux heat strips whenever the heat pump goes into a
Some systems will also ( but not always, by any means ) have an outdoor
thermostat (as an option ) that will lock out the heat pump altogether once
the outdoor temp gets below some set point so that on a call for condensor
startup the signal will be bypassed and will instead energize the aux heat
It all depends on the unit and the installer and the decisions that were
made by both when it was purchased and placed into service.
Doubtful anyone is likely to go through the tedium to determine which might
be the actual case over the internet--especially when we dont even know if
the OP owns a meter or knows how to read the schematics for the unit in
Suffice it to say if the unit runs constantly, letting it run is probly the
most energy efficient thing to do, and then if the house still gets too
cold, turn on the aux heat also--but do realize this will make for a rather
largish utility bill.
Just to clarify one thing here, not all outdoor stats are to lock out the
heat pump. Some outdoor stats lock out the aux heaters until it gets cold
enough outside, thus preventing them from coming on when someone thinks the
thermostat is an accelerator like on a car. All installations are different.
Good post Precision.
I have a two stage 16 seer and it does a great job till 16 degs and then it
switches over to n/gas. This month in Nebraska, bitter cold, gas bill
$84.00. I would suspect my electric to run about the same, as was the case
last winter.Winter of 04 gas and elec bills never exceeded $168 combined.
I live in a part of the world where we burn gas, oil, propane. Heat pumps
hardly ever seen.
Thus said, I'd have to guess your heat pump is doing darn near nothing at
zero F, and it's probably relying about 99% on heat strips.
We have several heating guys on this group (I have 3 years experience as a
heating installer). The guys can be counted on to flame me, which will help
warm your house.
On Sun, 23 Jan 2005 01:38:55 GMT, "Stormin Mormon"
Damn Stormy. Why blurt out such ridiculous shit like that? Go grab any
heat pump and pull the freaking access door off of it. Now read the
damn thing. Its called a "Performance Chart" and it tells you some
silly little information about the unit like:
THE PERFORMANCE of it! You'll be very suprised. Now, try something
else. Go grab the door off of a 14 SEER heat pump or higher. Wow! Even
Now go read damit. Learn something for once.
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