A/C vs Heat Pump With Old Gas Furnace

[easyotter]

Hello, brand new to the site and have been trying to absorb the info.

I have 18 year old 5 ton A/C unit that is on it's last breath - but had replaced the furnace in an emergency 5 years ago with a Goodman single stage 80%. House is a 3 story 2500+ sq feet on two finished floors in Washington DC area. I'm told that it's not possible to make the existing furnace a variable or 2 stage.

I had been considering a Trane matched system replacement XV95 furnace with a XL15or XL16 A/C - but then started to consider adding a XL15 or XL16 heat pump instead so as to reduce initial costs and keep the five year old Goodman furnace that is still working fine (though less efficiently and noisier) as the backup.

I've read some positive posts on a split system - but none that pertain to mixing brands with an older less efficient furnace. Does this make sense or asking for trouble? Appreciate your advice and insight.

[big sky hvac]

If you see your self staying in the home for at least 5-10 years, then I would replace the entire system and go with a variable speed 90%+ furnace. If you were looking into a more efficient A/C or heat pump, it would be pointless to install one with a 80% furnace w/psc motor,IMO. To get the most efficiency out the system, you'd want to have a variable speed blower motor in the furnace. For me personally, heat pumps have their place, but not everywhere in the country. If your average winter temps are below 32*F for extended periods of time(weeks to months), then I don't think heat pumps are a good investment. In milder winter climates when the average daytime highs are in the 40*'s, I think heat pumps are a great option for heating. It also depends on your comfort level. Heat pumps have a relatively low temp rise compared to a furnace, so they feel "cooler" when they're running. Some people would rather have the air feel "hot" instead of "warm". It really comes down to personal preferance and whether your climate is suited for a heat pump. What I tell people when they ask me about efficiencies is to look at it this way: what is the longer season you have, heating or cooling. This will help to determine what type of equipment to buy, when you're on a budget. If your heating season is longer, invest in a higher efficient furnace. If your cooling season is longer, invest in a higher efficient A/C. If you have the money to go with higher efficient equipment on both sides, you can always do both. In my part of the country, I recommend higher efficient furnaces and 13 seer A/C's. The ROI on a 95%+ furnace will be quicker up here than on a 16 seer A/C(which we may never see a ROI up here). Our cooling season is only about 4 months, so it doesn't make sense to go with higher seer here. :.02:

[aircooled53]

Hello, brand new to the site and have been trying to absorb the info.

I have 18 year old 5 ton A/C unit that is on it's last breath - but had replaced the furnace in an emergency 5 years ago with a Goodman single stage 80%. House is a 3 story 2500+ sq feet on two finished floors in Washington DC area. I'm told that it's not possible to make the existing furnace a variable or 2 stage.

I had been considering a Trane matched system replacement XV95 furnace with a XL15or XL16 A/C - but then started to consider adding a XL15 or XL16 heat pump instead so as to reduce initial costs and keep the five year old Goodman furnace that is still working fine (though less efficiently and noisier) as the backup.

I've read some positive posts on a split system - but none that pertain to mixing brands with an older less efficient furnace. Does this make sense or asking for trouble? Appreciate your advice and insight.

Get a new high eff. coil for Goodman and new condenser 410a. Keep the furnace and get a good thermostat..

[BaldLoonie]

Don't go with a 2 stage unit but no reason you can't go with a single stage machine and keep the old furnace. Going above 13 SEER probably won't do much good for now, especially with Trane, but if you later go with a matched variable speed unit, you could get the SEER you are paying for.

For example, the XR15 heat pump on std furnace will top out at 13.25 SEER. You paid a lot for .25 SEER point gain, peanuts.

A Goodman SSZ14 will get 14 with standard blower and cost lots less. And make aircooled happy :D