Central AC vs Heat Pump for replacement AC?

Ron Jones

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Location
Indianapolis area
My AC unit is most likely on it's last legs. It's about 12 years old (Janitrol) and uses freon. I want to be ready when it gives up and quits. We have an 8 year old 92% (IIRC) efficient natural gas forced air furnace (Lennox in good condition). When it's time to replace the AC would it be wise to go with another AC or change to an air to air heat pump using the furnace as the back up. Any advise from the vast knowledge of the Family is most welcome! Around Indy the summers usually get to the high 80s or low 90s and very humid. The winters may go subzero for a few days; maybe more that once a season.
 
Look at what your utility bill is in the winter when you use gas for heat . If it is definitely lower than your spring/ summer bill I would just replace the a/c. If the winter heating bill is higher then your summer cooling bill you might want to consider a heat pump. Just my 2 cents.
 
The heat pump would reduce your dependence on gas for heat for the moderate temps, but it's not a cure all. Heat pumps get really inefficient below about 30 deg or so. but you could use it for AC and heat for spring and fall saving on the gas bill. You'll also have to deal with the ducting issues too. AC ducts are generally in the ceiling as cool air falls as apposed to heating ducts which are in the floors so the hot air raises.

Mike
 
What touplin said. I wouldn't think it would be a good choice that far north but they maybe? AC part will work fine. Even here in the sunny south we have to use the backup heat in winter a few times each year. They just don't do well in cold weather. No heat in the air to steal.
 
Here is a solution you might consider - a geothermal heat pump system. Basically it uses the earth as the source of heat in the winter and as a coolant in the summer. A heat pump system looping through coils in the ground takes advantage of the earth's constant temperature below a certain depth. In a city or small lot situation you have to drilll down for the ground loops versus trenches where you have the space (drilling is more expensive).

Initial cost is higher, but the more efficient transfer of energy to and from the earth means you will spend less money operating it. With construction services being in the dumps your cost to install should be a bit lower right now and grid energy costs never seem to drop right now would be a good time to look at these systems. Taking the longer service life of new quality equipment and possible energy rebates payback vs a conventional air exchange system is probably acceptable if you plan on staying in your house for another 7 years. I believe almost all of these systems are considered energy star compliant.

I know I will use it in my house here in southern California when I do my addition/remodel.

Here are some web sources for information -
http://en.wikipedia.org/wiki/Geothermal_heat_pump
http://www.consumerenergycenter.org/home/heating_cooling/geothermal.html
http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12640
http://www.thisoldhouse.com/toh/article/0,,20162296,00.html

Cheers.
 
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