My wife and I purchased our house last October and planned to replace the original HVAC system from 1994 next year. However, that changed after we had our furnace inspected and serviced last week. The tech told us the inducer motor was going bad and should be replaced. Instead of putting $400-500 into it, we decided to upgrade now.

Original Furnace: Heil 9000, model # NULSO75BG04, propane
Original AC: American Standard Allegiance 10 - model # 7A0030A100A0

Here are a few details of our place:
- Located in central North Dakota
- 4408 finished sq ft (1032 top floor/loft, 1688 main floor, 1688 basement)
- Built in 1994 using Enercept SIPS (vaulted ceilings, no attic)
- PerfectAire Model 8100 Fresh Air Exchanger
- Propane: $1.62 average last year
- Electric: Facility charge of $14/mo - First 1000 kWh $.0777, Next 1000 kWh $.0690, $.0600 after that

I went to the Degree Days website and downloaded the following info. I ran the report for the last two years since this past winter was pretty mild and the previous one was more typical of a ND winter.

..................HDD.....CDD
10/1/2010.......557.....20
11/1/2010.......1126....0
12/1/2010.......1686....0
1/1/2011........1864....0
2/1/2011........1498....0
3/1/2011........1437....0
4/1/2011........758.....1
5/1/2011........399.....6
6/1/2011........118.....95
7/1/2011........16......270
8/1/2011........46......175
9/1/2011........276.....66
Total...........9781....633

10/1/2011.......519.....28
11/1/2011.......992.....0
12/1/2011.......1255....0
1/1/2012........1370....0
2/1/2012........1253....0
3/1/2012........748.....10
4/1/2012........562.....11
5/1/2012........272.....51
6/1/2012........79......171
7/1/2012........14......325
8/1/2012........104.....171
9/1/2012........288.....84
Total...........7456.....851

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Last Tuesday and Wednesday, I called five area companies (Coleman, Lennox, Ruud, Trane, York) and as of today, I have only heard back from the Trane and Lennox dealers (the Ruud dealer that I used to service my old system hasn't even called me back yet!). I received quotes from both and feel more comfortable with the Lennox dealer.

Below are the quotes exactly as they were written.

Option 1
Lennox SLP98UH090XV48C 98% Modulating Variable Speed Furnace with LP Kit
Lennox XP17-036-230 Single Stage Heat Pump
Lennox Cased A-Coil
Lennox Healthy Climate Air Filter and Cabinet
Lineset, Whip, Pad & Stand
PVC for Combustion Air Intake and Exhaust
Condensate Drain Material
Lennox icomfort Wi-Fi Thermostat
Supply and Return Air Plenums
Installed Price - $$$$$

Option 2
Lennox SLP98UH090XV48C 98% Modulating Variable Speed Furnace with LP Kit
Lennox XP16-036-230 Single Stage Heat Pump
Relay kit to make compatible with icomfort thermostat (price charged separately when released)
Everything else the same
Installed Price - About 5% higher than Option 1 (plus relay kit price when released)

Option 3
Lennox SLP98UH090XV48C 98% Modulating Variable Speed Furnace with LP Kit
Lennox XP21-036-230 Single Stage Heat Pump
Everything else the same
Installed Price - About 25% higher than Option 1


We plan to be in our house for the next 25-30 years so we'd like a very efficient, comfortable system. Based on the quotes, it seems like Option 1 or 2 would be the way to go.

Am I better off going with the single or two stage heat pump? Or doesn't it make much difference?

Any advice/suggestions/recommendations are gladly accepted.

Dave