How well do heat pumps work?

[thedarkwolf]

From what I have seen they are not good in extreme climates, real hot or real cold, but what is considered to hot or to cold? I live in an area where the summers are mainly 80s with a few mid 90s and winters are mostly mid 30s low 40s with a few dips into the 10s and 20s. I figure it can handle the 90s but what about the 10s? I don't wont to freeze my ass off and have the pump running constantly on those nights we hit the 20s or 10s. How do these cost compared to a furnace and seperate a/c to operate. The reason I am asking is one of the houses I looked at today had one.

Thanks for any info

 

[Ronstang]

Heat pumps are best used where space is an issue. I have one at my lake house and it works quite well, the only problem is that I hardly ever use the heat so now the reversing valve is stuck in the cool position. Their proper operation is also dependant on the correct amount of refrigerant. If is is even a little low the heat will not work properly.

The real question you have to ask is how efficient are they? I don't have any recent data so you might want to compare their efficiency to that of a conventional AC/furnace. Weigh the costs of install, the approximate costs to run per month, and then calculate which will be the cheapest over it's expected life span.

I don't think a heat pump is as efficient as a conventional AC/furnace but I have no choice at the lake since I have no natural gas supply.

 

[SavageDubz]

Ronstang....does your name mean that you got a mustang...if so, what year?

 

[Viper GTS]

Heat Pumps 101

[EDIT]Dammit, misread the question. Still a good site.[/EDIT]



Viper GTS

 

[Ronstang]

SavageDubz,

Yes it does. I currently have two. A 1966 Shelby GT350H and a currently under construction Restomod 1966 Fastback with fuel injected 5.0.

Actually my friends have alwaoys called all my Mustangs and the ones I have modified for other people Ronstangs. I have been building/working on Mustangs since 1979.

 

[thedarkwolf]

Think I might of found some of the info I was after

AIR-TO-AIR SYSTEM

The evaporator (outside the house) absorbs heat from the outside air, even when the temperature if as low as 20ºF because the
refrigerant within the evaporator is at a lower temperature. This unit is economical where winters are relatively mild and the average
temperature is above 25ºF. In climates where temperatures below 0ºF are common, auxiliary heat (electric, oil, gas or propane
system) is needed since the heat pump is not capable of carrying the entire heating load.

During periods of freezing temperatures, the outdoor evaporator fin coils become covered with ice and the heat pump goes into reverse
(cooling mode) and heat from the house is used to defrost the coils. This is accomplished by either a demand-defrost which uses
sensors or a time-temperature defrost which activates the defrost cycle at preset intervals when the temperature drops below a
specified level. During the defrost cycle, the auxiliary heat system is activated to warm the now cool air being provided in the house.


Still haven't been able to find much on how much they cost to run other than "they are extremely efficiant" from people wanting me to buy one . I think it could probably handle our winters but I would want another heater or two for backup on those few really cold days. This is the second or third house I have looked at that had heatpumps so they must work ok here.

 

[Sluggo]

From my experience, heat pumps will work "OK" down to about 10 degrees. The biggest problem is that people do not find them as comfortable as a gas furnace. The reason is because the air a heat pump puts out of the vents is not as hot as air from a gas furnace. Since the air is cooler, people always said they felt a draft.

EDIT

Just because several houses have a heat pump, dont be so quick to assume that they work good. A few years back the electric companies offered HUGE rebates on heat pumps to entice people to buy them. So lots of houses have them, and never use them except as an A/C unit.

 

[Soybomb]

My understanding is that they are very efficient for cooling and heating until you're tlaking about the extremes. I've got a heat pump in my apartment and was instructed that when it falls about 20 degrees outside to click the switch to turn on the furnace. So I'd assume its pretty efficient for the landlords to spring for both a pump and furnace.

 

[Ronstang]

Soybomb,

I don't think the switch is for a funace. The switch is for "emergency heat" which is usually supplied by electric heat strips which are very inefficient.

 

[Sluggo]

Here the switch is for a gas fired furnace, it is also marked emergency heat. Most people with heat pumps here, use the gas fired furnace for all heating since it is more comfortable and more efficient.

 

[thedarkwolf]

Well if nothing else my parents are putting a new furnace into there house since they are installing a/c so I guess I could hold onto their old furnace. Then if the pump can't handle it I could plumb it into the system for the really cold days.

 

[Belegost]

I lived in a house in San Diego (very mild climate) using a heat pump system for about a year, it sucked. It was far more expensive to run then the natural gas furnace in the house I moved to of about the same size, and it didn't heat very well. Like someone mentioned above the air coming out of the registers is not very warm which leaves you feeling like a cool wind is blowing.

Post Script: In case anyone thinks this was some old lousy system: the pump had been installed before I moved in by the landlord after the last tenants left, it was a good model as far as I could find out.

 

[db]

Heat pumps are best suited for moderate climates.

If you need to run a humidifier, a heat pump has a harder time picking up the moisture since the air temp is not as high as a gas-fired furnace.

In a *moderate* climate you will save money since the heat is picked up from the outside air instead of paying the gas or electric company for fuel.