My husband and I want to replace our old furnace and defunct central air sy
stem. We have called four contractors for estimates. Each one of them has t
ried very hard to sell us a heat pump. Several of our neighbors who got hea
t pumps are quite unhappy with them as their electric bills have skyrockete
d. Our only choice in this location is either propane or electric. Our curr
ent furnace runs on propane and we want the new one to do so also, just mor
Why this push to sell people heat pumps? We live in Southwest Oregon. We no
rmally would run the air conditioning only 2 to 3 weeks per year. The furna
ce is mostly used to warm the house in the morning until we get the wood st
ove going. I can't see the big benefit of switching over to a heat pump sys
tem. Could someone explain it to me?
Thanks for any help you can give.
I think your neighbors experience plus your need for
minor amounts of heat before the wood burning stove gets
going kind of puts the nail in the Heat Pump's coffin.
I wouldn't do it.
Now, just in case you do not know what a Heat Pump is,
it is basically an air conditioner installed backwards
in your windows.
All refrigeration units are heat pumps. They pump
heat from one source to another destination. Your
house air conditioner is not actually trying to cool
your house. It is using the heat from your house to
heat the great outdoors. What you see as cooling is
the effect of removing the heat from your house to
heat the outdoors.
What the marketing weasels call a "Heat Pump" is really
an air conditioner with baffles such that it can turn around
the direction heat is being pumped without having to physically
turn the thing around in your window.
If all you need is a room heater for a tiny amount of time,
have you though of running a direct vent heater off
of your propane when you need it?
I am babbling now.
If it gets under 30 or 40 F the expensive electric heating will kick in.
OTOH: Since you use a wood burner and the furnace would only be on for a
short period, the bills would not be as high as any of your neighbors
who do not burn wood.
True unless your backup is propane. My setup only uses propane when it
gets really cold, say under 32 and when the heat pump is deicing, which
is a pretty short period of time. I bought the most efficient HP at the
time, which was 6 years ago. They have gotten even better now. But if
you temperatures are frequently below 20 for long periods, a heat pump
might not be the best option. Where I live that doesn't happen
frequently. I do end up using about 400 gallons of propane per year and
that's also for hot water, bbq and cooktop.
On another note, my heating guy is also a big fan of the Mitsubishi mini
split AC/HP. He told me the heat pump will work efficiently down to 0. I
don't know if I fully believe that and have honestly never checked. The
nice part is that if you have several of these in different parts of the
house, depending on the layout, you can shut off the one(s) where you
are not occupying the area. Plus they now have units where you can have
one outside unit and 2 inside air handlers. Of course, this unit can be
bad in my area, the AC runs all summer long from early May to late
September. Temp is not that high, usually not higher than 85, but
humidity is another story. I have a 2 stage compressor and it usually
only runs in stage one, providing lots of humidity removal with lower
On Friday, October 10, 2014 9:43:28 AM UTC-4, Art Todesco wrote:
I depends on what your definition of "efficiently" is. If he means
that the heat pump will generate more heat for the house than the
electric energy used to run it, it's true. But the coefficient of
performance drops with the temp. It might be 4 at 40F and 2 at 0F,
meaning that at the lower temp you're only getting half the heat per
kwh that you were getting at 40F. You're also getting considerabley
less heat period for the same reason. I think that's often the biggest
problem, that when you need it the most, it has the least capacity to
deliver the heat. That's when heat pump systems typically have resistance
heat or another source kick in. IDK if mini-splits have that too or not.
Simply to add if OP comes back...
Cooling efficiency is indicated by the seasonal energy efficiency ratio
(SEER), which is the total heat removed from the conditioned space
during the annual cooling season, expressed in Btu, divided by the total
electrical energy consumed by the heat pump during the same season,
expressed in watt-hours.
The HSPF rates both the efficiency of the compressor and the
electric-resistance elements. The most efficient heat pumps have an HSPF
of between 8 and 10.
"Energy Star" units must have SEERs of 12 or greater and HSPFs of 7 or
greater. When comparing units w/ electric resistance backup, check
their steady-state rating at -8.3C (17F), the low temperature test
setting. The unit with the higher rating will be more efficient.
In warmer climates, SEER is more important than HSPF. In colder
climates or in the OP's operational scenario the higher HSPF should be
the target if were to stay with the electric resistance emergency heat.
Of course, if go to gas/propane for that, HSPF is not applicable.
Surely shouldn't unless the unit is sorely under-sized or they're
demanding greater catchup than the thermostat "emergency heat" deadband
setting (which is generally default of 2 or 3F, pretty narrow band).
So as outlined previously, if they let the house cool overnight then go
crank the thermostat to 72F at 7AM or whenever, yeah, they'll knock 'em
on. OTOH, if the t-stat is left alone, a current generation, properly
sized unit should keep up well down into at least the mid-20s.
On Thursday, October 9, 2014 8:29:57 PM UTC-4, Todd wrote:
r system. We have called four contractors for estimates. Each one of them h
as tried very hard to sell us a heat pump. Several of our neighbors who got
heat pumps are quite unhappy with them as their electric bills have skyroc
keted. Our only choice in this location is either propane or electric. Our
current furnace runs on propane and we want the new one to do so also, just
e normally would run the air conditioning only 2 to 3 weeks per year. The f
urnace is mostly used to warm the house in the morning until we get the woo
d stove going. I can't see the big benefit of switching over to a heat pump
system. Could someone explain it to me?
If that's the main need for heat, I agree. A heat pump isn't good
at producing heat quickly when you need it the most, ie when it's real
cold outside. To raise the heat quickly or when it's real cold outside,
they typically rely on using resistance electric heat as a supplement.
On the other hand, last I heard, propane was very expensive. If you had
to heat a house entirely with that, didn't have a wood stove too, and
it doesn't get down to the teens or below often, then a heat pump could
makes sense versus propane.
For the given situation, I would agree that a propane or oil furnace
combined with AC probably makes the most sense. It would be interesting
to know more about the experiences of those neighbors. I would expect the
electric bill to skyrocket. It might triple in the winter. But if was
$100 and it went to $300 in Jan, you have to compare it to what they were
paying for propane. The overall cost could still be a lot less.
There are also hybrid furnaces, that combine a heat pump with gas too.
This disadvantage there is the upfront cost will be the highest, but it's
probably worth a look.
A heat pump doesn't use baffles. It reverses whether the coil
inside tha air handles is the evaporator or the condensor. With an AC the e
vaportator is always inside the air handler, the condensor is outside.
With a heat pump system, if it's cooling that's how it works too. When
heating, the condenser is in the air handler, the evaporator outside.
You always pumping heat from one place to the other.
My husband and I want to replace our old furnace and defunct central air
system. We have called four contractors for estimates. Each one of them has
tried very hard to sell us a heat pump. Several of our neighbors who got
heat pumps are quite unhappy with them as their electric bills have
skyrocketed. Our only choice in this location is either propane or electric.
Our current furnace runs on propane and we want the new one to do so also,
just more efficiently.
Why this push to sell people heat pumps? We live in Southwest Oregon. We
normally would run the air conditioning only 2 to 3 weeks per year. The
furnace is mostly used to warm the house in the morning until we get the
wood stove going. I can't see the big benefit of switching over to a heat
pump system. Could someone explain it to me?
Thanks for any help you can give.
Heat pumps work very well in areas where the temperature seldom gets below
about 25 or 30 deg for very long at a time.
They are also designed to be set at one temperture and not moved while in
the heat mode. They heat up slow and if the change in temperature is more
than about 2 or 3 degrees at a time, the electrical heaters come on and use
power very heavy.
If you are going to use a wood stove most of the time and just want a quick
warm up the heat pump is not for you. You will be on the electric heat
strips most of the time.
You may want to look into what is called a gas pack. It is an
airconditioner with gas heat. I don't know much about them, but sounds more
like what you want over a regular heat pump.
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No, no link. They are all over if you just do a Google search for gas
I used to live in a neighborhood that had about a dozen houses built around
1965. Not much insulation in the houses then. They had natural gas heat.
A neighbor had a gas pack installed in his house about 15 years ago, but I
never did ask him how he liked it.
Also the heat pump does not change baffles around. It changes heat transfer
by some valves that change the direction of the refrigerant in the coils.
Air always flows the same way.
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For those had have a bad time with air conditioners because
of the mold build up on the cold side coils, maybe using a
heat pump and turning it on heat for 5 minutes would
remove the problem.
Now to figure out how to help those with dust mite poop
allergies and their dusty air conditioner coils. I wonder
it a heat pump would get hot enough to burn off the dust?
It would be miserable for the sufferer for a few minutes,
but would get better after the house was aired out.
and defunct central air system. We have called
four contractors for estimates. Each one of them
has tried very hard to sell us a heat pump. Several
of our neighbors who got heat pumps are quite
unhappy with them as their electric bills have
skyrocketed. Our only choice in this location
is either propane or electric. Our current
furnace runs on propane and we want the new
one to do so also, just more efficiently.
We live in Southwest Oregon. We normally would
run the air conditioning only 2 to 3 weeks per
year. The furnace is mostly used to warm the
house in the morning until we get the wood
stove going. I can't see the big benefit of
switching over to a heat pump system. Could
someone explain it to me?
Sometimes, when otherwise intelligent guys act
like idiots, it's because there is a federal
program or rebate which offers a bucket of tax
payer dollars to them. I'm just guessing.
Living in PRNY, natural gas or propane are
cheaper heat than electric strips or heat pump.
I'd not have a heat pump in PRNY.
With the furnace job of heat recovery from night
cold till you can get the wood stove going, sounds
perfect for propane.
Christopher A. Young
Learn about Jesus
Maybe somebody who actually knows something can comment on this:
- A heat pump will mean that if you have a power outage, you will not
have the benefit of central heat because it would require
a much larger generator that you probably would want
- The same propane that powers your furnace could power a small
generator in event of a power outage.
- If you put in split AC units (where there's a little compressor/
condenser outside the house for each room with pipes running up
to a blower/evaporator below the rooms window you might be able
to AC at least one room during a power outage.
With propane onsite, you can get a vented wall heater
to warm one room while the power is out. Much better
Agree, about the generator.
As to the AC, a window unit will be much cheaper than
a mini split.
For an air-exchange heat pump, they'll work very well for consistent
heat down to the mid-20s or so. As another poster noted, the basic
idea is the same as the A/C cycle except the reversing valve puts the
reject heat into the house instead of outside during the heat cycle
(think of the cooling coils on the rear of your refrigerator -- same
idea; bigger scale). The heat that is moved from the source (the
outside air) to the house is clearly much more readily available the
warmer the outside air, hence the dwindling efficiency as outside temps
Newer units can easily keep up in the low 20s w/o the auxiliary
resistance heat strips _IFF_ (the proverbial "big if") the demand for
heat is not more than a couple of degrees differential to the
setpoint--iow, keeping the thermostat essentially constant. Most
control systems (thermostats) for single-stage heat pumps w/o special
interlocks will demand the "aux heat" when the demand is greater than
that. Thus, if one expects the furnace to kick on when the house has
been allowed to cool significantly over night and heat it up quickly,
unless the unit is sized very much over the nominal capacity for the
house size and/or is a multi-stage unit, the conventional backup heat
system will kick in. Normally this is simply resistance electric heat
which while very efficient (essentially 100%) unless the local utility
has special rates for electric heating, it's generally quite a lot more
expensive than the alternatives. As another said, it is possible to
specify gas aux heat with some units but you'll have to demand it in an
estimate/bid as it will rarely if ever be the offered choice.
The other alternative if you have the facility to be able to do so is
the "ground loop" heat pump which uses a water or buried loop in the
ground for the heat source instead of outside air. They thus do not
have the problem of dropping outside temperatures the air-exchange units
do. We had one in E TN and had the resistance aux heat interlocked with
an outside temperature measurement to prevent them from kicking in
unless the inside temps were >4-5F below the setpoint and the outside
temps were <15-20F. In the 12 yr or so, they never came on. The
downside is initial cost is a fair amount higher unless can do the loop
install while doing the initial ground work while building a house.
In your scenario, if you expect to continue to use wood predominantly (I
thought from my daughter who's in Olympia area that OR/WA were really
clamping down on wood burning?) I'd guess the propane would be the
better choice. If you were in a conventional heating scenario with the
above caveats I'd think the heat pump could be an effective solution as
well, but not to warm the house up from 60F to 72F in a short time every
That'll depend a lot on the locale...in those places w/ shallow water
tables or available surface water _might_ even be the cheaper
alternative. The ground loop system we did in TN was the first for the
installer there--he'd been putting them in at Tellico Village on the TVA
Tellico Resevoir where they simply dropped some pipe in the lake...one
has to always investigate all the possibilities. :)
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