I am going to purchase a air to air heat pump to adjoin my propane furnace. I have been advised by one company that a 13 seer is right for us. Another recomends nothing smaller than a 15 seer. We have a 1800 sq ft ranch located in Northern Ohio. I would appreciate suggestions and reasons before we puchase. Thank you in advance.
Depending on whether you live in the north eastern portion or southern portion of Ohio the average season run-time is only between 800 & 1000 hours.
So far this season run-time hours have been rather low in Ohio & southern Wisconsin.
I personally probably would not go above a 14-seer with a scroll compressor & a TXV evap-coil metering device.
I don't know if the Maytag iQ Drive System's inverter rotary technology is in a !4-seer unit. That variable capacity technology looks promising. I know they have it in their 23-seer unit.
These variable capacity rotary compressor technologies look promising for variable temperature high humidity climates.
I would do everything possible to reduce the heat-gain/heat-loss before doing the load calc & sizing of equipment.
Keeping your existing furnace limits options. Probably the best you'll get out of that is 14 SEER even if the outdoor unit is capable of more. The 2 stage units might do a bit more but not wise unless you have that brand's matching variable speed indoor section.
Remember that SEER isn't size, it's efficiency.
When choosing, look at all the numbers of a unit. SEER, HSPF which is heating efficiency, heating output which tells how much heat you get from the unit. Just because a unit is capable of X number of BTUs cooling doesn't mean it heats that well. A lower output means higher bills and cooler air.
I too got some quotes to replace my aging York system, and the contractor only quoted 13 and 14 SEER. Since I'm not replacing right now, and my system has other issues that must be addressed before that, I'm not addressing the SEER trade offs (yet).
I seem to recall some pros here mentioning when you hit 15 SEER and above you typically get a variable speed fan, and that variable speed fans could involve duct work changes. Please correct me pros.
From my perusing of this forum there seems to be a certain school of thought that 13 and 14 SEER is the sweat spot of payoff right now, and that the 15 SEER (on up) tend to provide more comfort without necessarily any energy savings.
I would get quotes for a number of units: 13, 14, 15 and up and post back what you are being offered. There may be various reasons to exclude each model, but won't know without the specific models. Make sure your quote includes the outdoor unit model number and indoor coil and anything else.
Also, make sure they do a manual j (aka load calc) to be sure the unit is properly sized. Also BaldLoonie could be right, there may be issues in mating it to your existing furnace that might negate expected savings. When you get those quotes, and re-post, include your current system specs, and the load calc numbers (heat loss and heat gain).
As someone wisely posted here, you heating/cooling system is one of the most expensive things you will do in your house, so take your time in getting it right (IE maximize your investment).
If your existing furnace has a standard PSC blower. 15 SEER+ 2 stage systems won't give you much of a benefit.
Westinghouse IQ are high SEER only, and you need their furnace/air handler to use it.
If you replace the furnace, and get a VS blower, you can take advange of the comfort features of a 2 stage.