Got a question regarding the realistic heat output from heat pumps.
Friend of mine living in South Texas has a hydronic heat pump system. Essentially a radiator run off a water heater providing the air handler the source of heat.
Overnight temps typically in the 30's. Daytime temps from the mid 50's to low 70's. Indoors the house struggles to reach 69 degrees.
I understand that heat pump systems aren't as effective as gas fired furnaces in generating heat but does this sound a bit weak?
What does this have to do with heat pump? No heat pump in sight here;
and there's nothing anyways close to enough information to judge where
the problems are with the system. Could be simply not a large enough
water heater, could be it's large enough but the heat exchanger isn't
sized adequately or the water flow or simply the setpoint is too low.
Or, perhaps the house isn't insulated and is as leaky as a sieve; no way
But, whatever it is, comparing to a heat pump isn't the answer.
On Wednesday, January 20, 2016 at 9:08:47 AM UTC-5, dpb wrote:
I assume what he means is that it's a hydronic system that uses an
air source heat pump designed for that purpose. And if it's struggling
at those temps, it's not good. But like you say, not much info to
go on. Like how old? Heat pumps have gotten a lot more efficient
and capable of delivering heat at lower outside temps in recent
years. And are being used in more places in place of propane
or oil systems. Certainly a heat pump system should work well
in South TX climate.
On Wednesday, January 20, 2016 at 8:19:42 AM UTC-6, trader_4 wrote:
You are correct. I was mistaken when using the words heat pump. System is hydronic only.
Curious does the water systems on these require any direct maintenance? Such as in hot water baseboard systems some require bleeding of air. Anything like that needed for hydronic systems?
I think the OP is describing something like an Apollo system, where there isn't a separate boiler for heat, but a large domestic hot water heater that runs through the heating coils.
I was skeptical until I saw one installed but that worked fine, in the Virginia climate. If this one isn't keeping up with the Texas climate then something is malfunctioning.
On Wednesday, January 20, 2016 at 2:12:23 PM UTC-5, Wade Garrett wrote:
Comfort and low cost to operate - what's not to like? I wouldn't want one in Wisconsin but about anywhere south of there they work fine.
Er, provided you size them correctly and install them correctly. I know you're happy with your contractor but perhaps this wasn't his skill set.
Guess that it depends on where one is at. I am happy with mine and so are
lots of others in the area. Most days are above 30 deg F in the winter. It
does get cold at night. Last two nights was about 15 deg and with the
thermostat set at 68 during the night, it seemed to stay there during the
If one is where it is below 25 deg most of the winter, then it may pay to
look into other sources of heat, or if the electricity is very expensive.
On Wednesday, January 20, 2016 at 3:12:27 PM UTC-6, TimR wrote:
I live in the upper Mid-South and in a 600 s.f. addition I had built onto
the back of my house 8 years ago I had a heat pump installed. The
heat pump does a great job on the addition and it's always toasty
warm back there. I was a bit skeptical at first as the original
portion of the house has a central gas unit installed but I've
been very happy with the heat pump.
Your guy may be different, but I never meet a general contractor who,
without real pressure from the client which doesn't happen on anything
except a custom build or a spec-built contracted for sale, didn't use
the cheapest system he could get. House in TN was that way when we
bought it; the initial HP (air exchange) was minimally sized and very
low efficiency and we were, consequently, much like your homeowner class
above. Was our first experience with a heat pump; we were not impressed.
But, when it failed after some 15 year or so, we still didn't have NG in
the subdivision and weren't any time _real_soon_now_ (tm) and didn't
really much cotton to having to have the LP tank so we bit the bullet
and installed a ground-source HP (Water Furnace brand). While the
excavation cost was high because we had to do it around existing drain
fields, etc., etc., instead of as part of new construction, when
finished it outperformed the old HP even on its best, early-life
efficiency by at least a third plus with the waste heat from A/C cycle
for hotwater option, it supplied essentially "free" hot water during
warm weather. And, exit air temp's from the floor vents, while not
quite what one gets from gas/oil forced air, were warm enough there was
none of that "chill factor" effect one got from the air-exchange unit
that was just above room temperature. Plus, the backup resistance
heating units were tied into an outside thermistor to keep them from
kicking on at anything above 15F or so and even on the few days there
down to 0F they never kicked on.
Newer air-exchange units are far better now that 35 year ago or so when
this system was new, but if I were doing new construction anywhere that
cheap NG isn't available I'd surely investigate thoroughly the option of
ground source HP.
On Wednesday, January 20, 2016 at 11:56:08 AM UTC-5, Chiefjim wrote:
Hydronic and what fuel source? You said it was run off a water heater?
Normally a hydronic system is run off a boiler. Sounds like this is
some half-assed DIY system. If it's really a water heater, it likely
doesn't have enough BTUs. Even worse if it's electric.
From what I understnad about the hydronic system is there is a water
radiator in the heat ducts. This only comes on if the air temperature
comming out of the heat pump coils is not enough to heat the house. Just as
the electric heat strips are for in the more normal heat pump.
If the outside air is only 30 deg, the heat pump should not have any trouble
at all keeping the house at 70 deg provided the house has enough insulation
, which it should if a heat pump is installed.
For many areas the temperature has to drop below 25 deg, maybe even lower
before the cost of operating the heat pump becomes more than gas heat.
It was 18 deg here the last 2 nights and I have the thermostat set at 68
deg at night and 70 during the day and the heat pump has no problem keeping
the heat at that temperature.
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