On 10/10/2014 8:48 AM, firstname.lastname@example.org wrote:
Not my experience in TN w/ the air-exchange unit prior to putting in the
ground loop (after 15+ yr on a builder-grade, cheapie initial).
It would occasionally, yes, but nothing nearly like that frequency and
generally, even though E TN is pretty humid, winters "aren't so much"
and icing really wasn't much of an issue (until the unit developed leaks
later in its life cycle, but that's a failure problem).
There are a couple things to consider:
1. The people with the "skyrocketing" electric bills are likely not
factoring in the reduced or eliminated propane bills. Far too many
people fail to do the full before and after calculations of actual cost
2. There are two types of heat pumps, air source and ground source. Both
types are very efficient and a good option to consider unless your
electric rates are abnormally high. If your climate has few days with
outdoor temps below freezing (when the heat pump has to switch to backup
heat) an air source heat pump is a good choice. For colder areas a
ground source heat pump would be the best choice since they can work in
any climate but cost more.
The key thing is to review the past year or two of expenses and
calculate the true costs for each option. If your A/C has not been
functional, this will of course bias your results so you can either
calculate on heating only, or dig back and find the costs when your A/C
was functional for comparison to the more efficient cooling from a new
If you are looking at a ground source (geothermal) heat pump, *do not*
be misled into vertical hole loop installation by contractors who are
invested in the drill rigs for such installations. Trenched horizontal
coil (not flat loop) installation has been proven to be the most cost
effective installation with no performance difference from other
installation methods. Trenched coil covers less area and requires only a
big Ditch-Witch trencher for installation, not an expensive drill rig.
Trenched coil is a vertically oriented coil of the plastic tubing in an
overlapping coil configuration - think a slinky spread sideways.
On Friday, October 10, 2014 10:10:08 AM UTC-4, Pete C. wrote:
Good point on the geothermal possibility. Only problem is the ones
I've seen details on, the payback was so long it just wasn't practical.
But if you have high cost propane, it would be worth looking into.
I replace an old oil furnace in a rental house with a heat pump with
electrical backup. Just like we have in our mfg home. Both in Central
Oregon. Ours worked quite well and was the cheapest heat around.
The new installation used a new programmable thermostat. I had the
company replace our home thermostat with a similar new programmable
The electric bill at the rental was now outrageous. Working with the
electrician and the heating company, we discovered a one degree
difference between the house temperature and the thermostat set
temperature would not only turn on the heat pump, but turn on the backup
electric heat elements. The renter's parents have the same system and
their backup comes on with a two degree difference.
The renter was setting the night temp 5-10 degrees cooler than the day
temp, so when the trigger time arrived, both the heat pump and the
electric backup came on and stayed on until the house warmed up.
Same thing on our home heat pump with the new thermostat.
The solution is to set the thermostat so a constant temperature is
maintained day and night. Ours is set to 72 degrees. this is also the
most economical use of heating. Once everything is up to temp, the heat
source only has to maintain that temp.
I do not see any option in the thermostat manual to set a specific
temperature difference value.
Don't blame the heat pump. It's the thermostat.
Paul in Central ORegon
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