where are you located, what is the cost per kwh for electricity and what is your cost for gas? And will this be a duel fuel system (HP runs down to 35F then gas turns on)?

what is mdl, size, age of "used" heat pump?

what is your area/location?

TD

I'm in central Missouri.

I'm at work, so I can't check the model of the heat pump right now. It's a 3-ton unit from 2006.

Price per kWh for gas is $1.52. Electric rates are 9.3 cents per kWh up to 1000 kWh, then 8.3 cents per kWh.

OK, I was able to find out the model of the heat pump. It's a Unitary Products model. If I wrote down the model number correctly, it's CH1036BCD1VF.

I had to read your post several times and I still may be confused.

You say that you have an old heat pump that is used for a/c only (can't be used for heat). It needs to have a coil in order to function. Where is that coil located? Since you say that it can't be hooked up to your old furnace, is the coil part of an air handler which is separate from your furnace?

What is the reason that the HP cannot be used for heating? If in a separate housing, there could very well be a control problem to use it in conjunction with your furnace as auxiliary heat, but you could use it exclusively, if economical, until temperatures drop, then switch to gas.

How do you use it for a/c if it's not 'hooked up'?

Please elaborate on your system.

V

sherry

like the previous post, I am confused about why you were unable to use the HP in heating mode.

But assuming the HP is in good operating condition and is correct size for your home, I see no reason why you would not want to use it. I would ask AmStd dealer to make an inspection of outside condenser and find out exactly what you have in the way of evap coil. If coil is not a matching coil of same brand, I would ask dealer to see if they can locate one. With condenser being only 3-4 yrs age, availability should not be an issue.

also you will need a thermostat for dual fuel application.

BTW, what size is your home and what size furnace are you installing?

IMO

Thanks for attempting to help me, everyone. Sorry for all the confusion regarding the set up of my current hvac system.

The previous owners were the ones who indicated that there was some sort of problem with using the heat pump in conjunction with the furnace when I asked about it in the process of buying the house earlier this year. It doesn't make sense that they wouldn't have used it for heating if they could, because the current furnace is expensive to operate.

As for the state of the current system, I'm relying on what I've been told by the contractors who have looked at it. My furnace is located in the crawl space under my house, and being claustrophobic, I'm not crawling in there myself to look at what's going on. Not that I'd know what I was looking at, anyway.

I do believe that the coil is separate from the furnace and the condenser unit. What I have been told is that the coil is completely enclosed within some sort of housing that would have to be disassembled to evaluate its condition or change it out.

Tiger--The house is 1500 sq. ft. The contractor recommended an 80000 BTU furnace.

sherry

still confused.

a question.

do you have two ductwork systems, one for the AC and one for the furnace?

also I would encourage you to get a load calc for correct sizing of your furnace. 80 KBTUs seems too large for a 1500 sq ft home.

post back.

TD

Tiger,

The ductwork is all the same.

I'm confused, too! But I think I'm going to go ahead and try to hook up the heat pump. Hopefully whatever kept the home's previous owners from using the heat pump for heating won't be an issue.

As far as the sizing goes, the contractor I've decided to use claims to have run some sort of heat calculation. He was very thorough in assessing the house before he made his proposal, so I don't really have a reason to assume that he's oversized the furnace significantly. It is an older house, so the insulation isn't great, and it has quite a few windows and doors, including two large picture windows. The other contractors all offered similar sizing--another one at 80000 and one at 75000.

Sherry

I was going to make a wild guess that the previous owners were cheap. They replaced a broken AC condenser unit with a used HP unit but didn't update any of the inside equipment. There is no reversing valve, or it defaults to cooling only. The HP unit runs in cooling only.

OR they never thought about making it a duel fuel setup. Hence the gas furnace and HP run at the same time, which would not be good. This would be fixable with a new thermostat capable of dual operation. But this should be part of your furnace upgrade.

You might also ask about a quote on an 80% system.