[Pizza anyone?]

Hello. I moved from the Rust Belt, where a furnace is a furnace, to the midSouth (North Carolina), where a furnace is a heat pump.

The one in this house runs for a half-hour or so when it wants to heat, and it certainly isn't very committed about it, as the air coming from the vents is only about 85 degrees. Since people are 98.6 degrees, I get wind chill from the furnace vents. If I'm getting wind chill from the furnace, that really seems wrong.

It's a rented house, and it's kind of junky all around, but don't listen to me. I'm not a big fan of postwar houses.

But is running for half an hour or more wrong? Is a seemingly feeble 85 degrees wrong?

Thank you kindly.

 

[crabjoe]

I don't know what you have your temp set at but lets say you want it 70F.. If so, 85 sounds about right .. that's aprox a 15F temp split. It's probably a bit higher if the temps are taken just before and after the evap coil...

As for run time, 30 mins is nothing... I'm in MD and it's mine runs for like 2 hours when outside temps are in the low 30s. Heat pump are build to run non-stop, if need be.

BTW, you should have electric heat strips in your air handler. If your heat pump can't keep up, your electric heat strips should energize and supplement your heat pump.. When that happens your blowing air should feel a bit warmer than when it's just the heat pump alone. Me... Because I have a gas furnace, I have my setup programmed to lock out my heat pump and run on the gas furnace, if the outside temp is below 30F.

So to summarize, 30 mins is not odd for a heat cycle run and neither is 85F for the supply air... assuming your indoor temp is around 70F.

 

[user_12345a]

The split you're supposed to get depends on the outdoor temp and indoor airflow.

85f is fairly low, but if you have ducts in an unconditioned space, the fan speed is set too high, or the outdoor temp is low, it may be okay.

A heatpump can not operate like a furnace. The airflow relative to heating capacity is high; the best you can hope for is around 100f air when it's mild vs 120+ from a furnace. Supply temp drops as it gets colder out.

Cycles will be long due to the lower capacity. Traditional heatpumps are good when used in the correct application; ie climate with milder winters combined with affordable electricity. In colder climates they need a lot of supplemental heat below 20-45f depending on sizing and insulation. The supplemental heat whipes out any savings of running a heatpump compared to a fossil fuel furnace.

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At the correct airflow, 400 cfm per ton, at 47f outside, split should be 28f.

 

[supers05]

Every piece of equipment will have different ratings. But 85* sounds completely normal. 30 min sounds perfect.

It is possible to get warmer supply temps, but you have to mess with fan speed. I wouldn't recommend touching it without pressure gauges at the very least. A pro friend would be ideal.

TBH, you'll get used to staying away from the air flows. You'd feel mighty cold sitting in that same air flow during summer when the a/c is on too. It's just a trait of heat pumps.

Cheers!

 

[beenthere]

As said by others. Depends on the outdoor temp, and the indoor temp, as far as how warm the air blowing out will be. So what was/is the outdoor and indoor temp when its blowing out 85°F air.

 

[SeniorSitizen]

I have a feeling the vast majority aren't told of this nearly non stop blowing of air with a less than desirable temperature but rather the money it will save.

We were told by our HVAC contractor and have a heater. If it were any cheaper to operate, the gas company, electric company and repair personal would be paying us to operate it.:smile:

 

[Pizza anyone?]

I have to confess, I measured the temperature but not the time. The run time is over an hour.

I also have to confess, I have a physical condition by which I need a higher temperature than most people. At 75 I'm shivering, in pain and misery.

Which I wish I could do something about. This is home, it's supposed to be peaceful and quiet. It's just not so great to have a blower roaring away all the time.

But maybe this is just another example of the progressive cheapifying of everything. The constant noise and draft is tawdry, but it's supposedly cheaper than a real furnace. As though cheaper being tawdry is news.

It would be nice if quality-of-life figured in here somewhere.

But anyway, thanks to everyone for the orientation. I guess the correct answer is "put up with it".

 

[roughneck]

A properly installed system shouldn't be noisy, or feel drafty. Many are quick to blame equipment when it was the installation that's causing the issue. When I replaced the heat pump in my parents house, I got it to where you have to look at the thermostat to see if it's running. Duct system is nice and quiet, as is the unit. Discharge temps usually run around 95-100*, on an average winter day, with the set point at 74*. I keep the electric heat locked out above 40* outdoor air temp.
Heat pumps are great, providing they are in proper working order.

 

[beenthere]

What is the RH level in your house. You may need a humidifier. Which can make 72 feel warmer then 75.

 

[Bob Sanders]

A properly installed system shouldn't be noisy, or feel drafty. Many are quick to blame equipment when it was the installation that's causing the issue. When I replaced the heat pump in my parents house, I got it to where you have to look at the thermostat to see if it's running. Duct system is nice and quiet, as is the unit. Discharge temps usually run around 95-100*, on an average winter day, with the set point at 74*. I keep the electric heat locked out above 40* outdoor air temp.
Heat pumps are great, providing they are in proper working order.

Having absolutely no issues with mine and also have no issues with the low grade heat output (relative to to a furnace). The longer blower times at lower heat levels keeps the overall house at a more even temperature with less hot/cold pockets.

If you are used to a regular furnace though I can see why you may find heat pump operations a little odd.

As for run times, there are a lot of factors involved with that... outdoor temp, thermostat settings (cph values)... etc. Mine is set up to run as constantly as possible and at -18C (0F) it runs pretty much constantly on stage one, stepping into stage 2 maybe every 1/2 hour or so.

Your output temp will depend completely on how cold it is but 85 sounds pretty reasonable for a heat pump. To confirm that though, your heat pump should have a spec chart (you can most likely download if you don't have it) which will tell you what your delta should be, and it's rated output at a given temp.

Saving money? I was on resistive electric heat last year and there is a BIG difference in the bills this year. Since October when our heating season started we have saved a total of $320 (and out power is cheap here... $.074Kwh). The savings is going to be pretty substantial of the course of an entire heating season.

 

[sktn77a]

OP - What temperature do you have the house set at? Assuming its 75 (and you're shivering!) that would be roughly 10 degree split, which is a bit low. Please provide more details (outside temp, inside temp, location in NC for humidity estimate). It may be that the unit needs service.

 

[throrope]

All electric heat pumps typically include an electric heating coil or electric strip heater as noted above. Traditional thermostat's engage the electric heat when the space temperature is 3 degrees less than setting.

Heat pumps can't operate when outside temperatures are in the 30s. Hence the electric heating coil, which is called emergency heat or auxiliary heat.

I expect for all be a few weeks a year, the heat pump will be within its operating range.

If I were footing the utility bill of a renter in NC, I'd cut the wire driving the electric coil since it likely won't be noticed and really eats money. I'd also have a thermostat that locks out operation above say 72 degrees.

I suggest using an accurate thermometer and record what your place is maintaining. If you're not happy with what you see, start complaining. Your local building department may help if the place doesn't have adequate heat.

Beyond that, like above a humidifier likely will help and is a good idea at your age, but adds work. I'd also look for window gaps and similar sources of cold air drafts.

Good luck and keep us posted.

 

[Bob Sanders]

Heat pumps can't operate when outside temperatures are in the 30s. Hence the electric heating coil, which is called emergency heat or auxiliary heat.

Not true at all. Mine was operating fine at 0F (breakers on the heat strips off).

A properly sized HP ( of reasonable quality) should be able to handle to at least -5F

 

[supers05]

Mitsubishi HP work significantly well to -25 C and below. I've recently spoke to a contractor that has used them for primary heat. (no aux heat)

It's quite possible to have warmer temps for heat Pumps. However unless you have gauges, and some help from us, or a pro, it's not going work out well.

Cheers!

 

[beenthere]

All electric heat pumps typically include an electric heating coil or electric strip heater as noted above. Traditional thermostat's engage the electric heat when the space temperature is 3 degrees less than setting.

Most heat pumps have an aux heat means, but not all of them.

Heat pumps can't operate when outside temperatures are in the 30s.

Heat pumps have been working in outdoor temps of 30 and far less since I know about them, which goes back to the 70s.

Hence the electric heating coil, which is called emergency heat or auxiliary heat.

Its only called emergency heat, when the thermostat is switched to emergency. Other wise, when used in conjunction with the heat pump, it is aux heat.

I expect for all be a few weeks a year, the heat pump will be within its operating range.

If I were footing the utility bill of a renter in NC, I'd cut the wire driving the electric coil since it likely won't be noticed and really eats money.

This would probably violate federal housing regs. And at min you would be required to prove that the heat pump alone can maintain 65°F at design temps. The state itself may have a higher min indoor temp, that it must maintain. And they would require proof that the heat pump only can maintain that temp.

I'd also have a thermostat that locks out operation above say 72 degrees.

I suggest using an accurate thermometer and record what your place is maintaining. If you're not happy with what you see, start complaining. Your local building department may help if the place doesn't have adequate heat.

Beyond that, like above a humidifier likely will help and is a good idea at your age, but adds work. I'd also look for window gaps and similar sources of cold air drafts.

Good luck and keep us posted.

Most people switching from gas or oil heat, find a heat pump lacking compared to their old heat.

 

[crabjoe]

Most people switching from gas or oil heat, find a heat pump lacking compared to their old heat.

I've been on gas (LP) heat for 10 years and just added a heat pump because the crazy prices of LP since 2007... I should have done it earlier, but my AC unit was from 2004...

When I 1st started using the heat pump, when outside temps are 30F+, I thought it wasn't working because the air wasn't warm to hot .. I was lucky in that I have a Honeywell Prestige with gives me temp split... so I knew it was working...

It took a couple weeks to get use to it, so now I'm fine with the way the heat pump works ... that is until the gas furnace kicks in.. Gas heat is so much warmer that when it goes back to heat pump mode, it puts a frown on my face... :vs_frown: Still I know in the long run, my new hybrid system is better for heating costs...

Bottom line ... heat pump heat does the job (maintains indoor temp), but when it's generating, it sux compared to propane heat.

 

[throrope]

Not true at all. Mine was operating fine at 0F (breakers on the heat strips off).

A properly sized HP ( of reasonable quality) should be able to handle to at least -5F

Thanks - This is likely an old rule of thumb and shouldn't be used for troubleshooting no matter how old the thumb. Specifications from manufacturer and model number dictate performance.