Heat Pump versus Furnace

[RNMedic]

Okay, live in Ohio and have a propane furnace, older model 80% efficiency. DO the newer heat pumps really work? or should I just get a newer 95% efficiency furnace? Install will be done by my oldest boy, this is what he does. I have heard his side but looking for some more info to mix in the pot. TIA John

 

[Darky]

What exactly is a heat pump, aside from something that pumps heat..

 

[RichP]

Depends on the heat pump, the 'southern' models don't go very deep but then they don't have to have high output. The best method entails a field like for a septic system and about 6-8 ft down or a well type that goes about 100-150ft down. Those two types work very well and will supply a constant ~58F all year long.

For darky, a heat pump works like cooling system in the jeep, it pumps fluid down underground where the fluid is cooled or heated, depending on your point of view, and then blows the heated/cooled fluid over a core. Once you get down a good distance the earth temp is a constant. The 'southern' models use a small amount of coolant, the other two use a pretty big amount that is pumped thu hoses down and back. The temp is like 58F, depends on how deep you go, I seem to remember for every 10ft you go the temp goes up 1 degree.
Basically the heat pump supplies a constant air temp over a coil which means you only need to either heat or cool 5-10f with some kind of supplement.

 

[Ironmen77]

Depends on the heat pump, the 'southern' models don't go very deep but then they don't have to have high output. The best method entails a field like for a septic system and about 6-8 ft down or a well type that goes about 100-150ft down. Those two types work very well and will supply a constant ~58F all year long.

You're talking about a ground source heat-pump here. They also make air to air heat-pumps. Although not as effecient as a ground source still more effecient than a 90% plus furnace.
The best would be a heat-pump with electric back-up. Next best would be a heat-pump with gas back-up.

 

[RNMedic]

yup air to air, not geothermal type, And in essence an A/C that reverses the way it works

 

[Ray H]

Im not a fan of heat pumps. They arent very efficient in colder climates. If the difference between the outside tempurature and the inside target tempurature is greater than about 30 degrees, the efficiency of a heat pump goes to crap real quick. They work well at moderate tempurature differences like in the summer, spring and fall, but in the winter, they suck.
To heat my house I chose all electric. I have a heat pump that I use 3/4 of the year and baseboard that I use in the winter. That seems to be a good combination. my next house will be setup the same way.
If you are simply looking for a heat source and not A/C also, I would recommend electric baseboard. I know, I know, alot of people will tell you how inefficient that is but when you figure they cost alot less to install and the maintenance costs down the road is virtually zero, I think you come out ahead in the long run.

 

[RichP]

Im not a fan of heat pumps. They arent very efficient in colder climates. If the difference between the outside tempurature and the inside target tempurature is greater than about 30 degrees, the efficiency of a heat pump goes to crap real quick. They work well at moderate tempurature differences like in the summer, spring and fall, but in the winter, they suck.
To heat my house I chose all electric. I have a heat pump that I use 3/4 of the year and baseboard that I use in the winter. That seems to be a good combination. my next house will be setup the same way.
If you are simply looking for a heat source and not A/C also, I would recommend electric baseboard. I know, I know, alot of people will tell you how inefficient that is but when you figure they cost alot less to install and the maintenance costs down the road is virtually zero, I think you come out ahead in the long run.

Yea, my whole house is electric, heat, hot water, and A/C window units that I want to replace with an outside unit and those small wall units.
A new heater for a room is under $50, our electric bill for our house is $170 a month but that will go down now that I shut down over a dozen servers that each have 550w power supplies running 24x7 for past 4 years. I'm figuring it should drop to around $120. I'm also looking forward to the day when solar panel prices drop and I can add sufficient solar panels to power the house at which time conversion will be simple. Though this past summer we never needed the A/C up here, dam global warming.

 

[Ironmen77]

Heat-pumps are alright if sized properly and used properly. With electric heat the heat strips should phased in as the temp goes lower. For instance heat-pump alone to 35 deg. Add 1 heat strip under that, add another at 30 deg., all electric below 25 deg., or some comb. like that.
Heat-pump with gas should be something like heat pump to 35 deg. below that a dual fuel control shuts the heat-pump off and you use gas furnace. All these temps given can be changed to fit your comfort.

 

[RNMedic]

where can I find baseboard heaters for that price??

 

[tbburg]

You're talking about a ground source heat-pump here. They also make air to air heat-pumps. Although not as effecient as a ground source still more efficient than a 90% plus furnace.

except that an air to air heat pump pretty much stops working below 20-25 degrees. In Ohio, the only heat pump I would consider is a geothermal model(and they cost probably twice as much. However, they work more efficiently in BOTH the summer and winter. An air to air unit will be slightly less efficient then a similar sized straight air conditioner.

The best would be a heat-pump with electric back-up. Next best would be a heat-pump with gas back-up.

'Used to live in Ohio. All the heat pumps were REQUIRED to have a backup. In the "auxiliary/emergency heat" mode, they are less efficient then an equivalent electric furnace.

If you're used to gas heat, be aware that a heat pump doesn't put out "hot" air. The really good ones have about a 9-10 degree temp rise in clod weather(as in, if the room air temp is 70, the air out of the duct is 80)

My advice: If you can afford it, get a geothermal heat pump, if not, get a split system gas heat/elec. cool.
If you really want comfort, get in floor hydronic heating(which can be by conventional boiler/water heater or geothermal heat pump)and a conventional air conditioner(this is by FAR the most expensive option, but also the most comfortable, and most efficient.)

 

[Ironmen77]

In the "auxiliary/emergency heat" mode, they are less efficient then an equivalent electric furnace.

If you put your t-stat on emergency heat mode you by-pass the heat pump. Therefore it would be the same efficient wise. Electric heat/heat pump should be controled by outside t-stats allowing electric heat as needed.

If you're used to gas heat, be aware that a heat pump doesn't put out "hot" air. The really good ones have about a 9-10 degree temp rise in clod weather(as in, if the room air temp is 70, the air out of the duct is 80)

Heat-pumps w/electric heat staged in can put out 120 deg. air.
Heat-pumps w/gas furnace back up turn off the heat-pump at a pre-determined outside temp and run on gas heat until the t-stat is satisfied.

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[tbburg]

If you put your t-stat on emergency heat mode you by-pass the heat pump. Therefore it would be the same efficient wise. Electric heat/heat pump should be controlled by outside t-stats allowing electric heat as needed.

Every H/P I've worked on, when you put it in "emergency heat" mode, the fan ran continuous. In "auxiliary heat" mode, both the heat pump and heat strips run. In both cases, the H/P will use more juice then a stand alone electric furnace.

Heat-pumps w/electric heat staged in can put out 120 deg. air.

Heat-pumps w/gas furnace back up turn off the heat-pump at a pre-determined outside temp and run on gas heat until the t-stat is satisfied.

I was talking about a heat pump running as a heat pump. A heat pump running a gas furnace back up isn't running in heat pump mode when the furnace is on, and is only as efficient as the gas furnace. Any real savings there?

I lived in south east Ohio(Athens) which is just about West Virginia. Our heat pumps ran in Aux. mode for probably 1/2 the winter. We had no direct apples/apples comparisons, but the apartments with the heat pumps had higher electric bills in the winter.(side note: a heat pump burns out in the winter, no one notices. The auxiliary heater quits, and we would get a service call.

I'm probably biased,(OK, I'm biased, I don't care) but I wouldn't have a heat pump as a primary heat source anywhere the average temp stayed below 35 deg. on a regular basis. If I was somehow stuck with one, I,d get a full sized gas or electric furnace, then I'd wire it with an outside thermostat so that when the temp dropped below about 40, the "auxiliary" furnace switched over to the primary, and the heat pump stayed off.

RNMedic: If you decide to get one, and are in their service area, AEP used to subsidize the cost of a heat pump. They'd cut you a check for the difference between a regular AC unit and a heat pump. 'Don't know if the program is still available. 'Might want to check your elec. co. May be a similar program available.

 

[RichP]

where can I find baseboard heaters for that price??

I replaced both the small ones in my bathrooms, got them at home depot, Just looked at another one I have for another room once I get around to painting it, made by Fahrenheit. thats a 48" one, don't remember what that cost. Uses a high voltage thermostat though.

 

[Ironmen77]

Every H/P I've worked on, when you put it in "emergency heat" mode, the fan ran continuous. In "auxiliary heat" mode, both the heat pump and heat strips run. In both cases, the H/P will use more juice then a stand alone electric furnace.

Thats different from my experence with them. On all the HP t-stats I've worked on emer. heat by-passes the first stage heat and runs second stage as the primary heat

I was talking about a heat pump running as a heat pump. A heat pump running a gas furnace back up isn't running in heat pump mode when the furnace is on, and is only as efficient as the gas furnace. Any real savings there?

No savings after the furnace comes on, but you save up to that point, therefore electric backup is the better choice.

I lived in south east Ohio(Athens) which is just about West Virginia. Our heat pumps ran in Aux. mode for probably 1/2 the winter. We had no direct apples/apples comparisons, but the apartments with the heat pumps had higher electric bills in the winter.(side note: a heat pump burns out in the winter, no one notices. The auxiliary heater quits, and we would get a service call.

If your HP runs only 1/2 the winter it is more efficient than electric heat. So wouldn't it save money?

I'm probably biased,(OK, I'm biased, I don't care) but I wouldn't have a heat pump as a primary heat source anywhere the average temp stayed below 35 deg. on a regular basis. If I was somehow stuck with one, I,d get a full sized gas or electric furnace, then I'd wire it with an outside thermostat so that when the temp dropped below about 40, the "auxiliary" furnace switched over to the primary, and the heat pump stayed off.

That's one way to do it. I prefer staging in electric heat along with it.

RNMedic: If you decide to get one, and are in their service area, AEP used to subsidize the cost of a heat pump. They'd cut you a check for the difference between a regular AC unit and a heat pump. 'Don't know if the program is still available. 'Might want to check your elec. co. May be a similar program available.

That was/is a great program worth checking into.

 

[tbburg]

Our heat pumps ran in Aux. mode for probably 1/2 the winter.

If your HP runs only 1/2 the winter it is more efficient than electric heat. So wouldn't it save money?

Didn't seem to, as I said:

We had no direct apples/apples comparisons, but the apartments with the heat pumps had higher electric bills in the winter.

 

[Matthew Currie]

What exactly is a heat pump, aside from something that pumps heat..

In short, a heat pump is a reverse air conditioner. It uses a closed refrigerant system to transfer heat from one place to another, rather than converting energy or fuel directly to heat. Since there's always some heat in any environment, even when it's cold, a heat pump can absorb that heat and transfer it to where you need it. But the colder the environment, the less efficient it is.

In areas where central air conditioning is common and winter temperatures mild, heat pumps are common.

Just about every motel I've stayed at in recent years uses heat pumps as individual room units. As some posts above mention, one option for colder climates is a geothermal heat pump, which gets its heat from underground, rather than from the chilly outside air.

We don't see many of them up our way. The hot setup in the north country these days is gasifying wood furnaces.

 

[westvirginia24976]

Quote:
Originally Posted by Darky
What exactly is a heat pump, aside from something that pumps heat..

In short, a heat pump is a reverse air conditioner. It uses a closed refrigerant system to transfer heat from one place to another, rather than converting energy or fuel directly to heat. Since there's always some heat in any environment, even when it's cold, a heat pump can absorb that heat and transfer it to where you need it. But the colder the environment, the less efficient it is.

In areas where central air conditioning is common and winter temperatures mild, heat pumps are common.

Just about every motel I've stayed at in recent years uses heat pumps as individual room units. As some posts above mention, one option for colder climates is a geothermal heat pump, which gets its heat from underground, rather than from the chilly outside air.

We don't see many of them up our way. The hot setup in the north country these days is gasifying wood furnaces.



Thank you Mr. Currie. There is an amazing amount of bad information in this thread. It goes to show that old wives tales are hard to put away. My absolute favorite is how hot water freezes faster even though there is more heat to be removed. Anyway well written post and I am outta here.