Single or Two Stage Heat Pump in ND

[Dave2425]

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

---------------------------------------------

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

[George2]

I would not go with an air to air HP in N.D. If you can wait, I would install a split geo-thermal system.

IMHO........

[BaldLoonie]

Geo would be great if affordable. Otherwise I'd sure have an air source if I had LP heat.

Look at all the numbers. In your area, concentrate on heating performance.

1st option: HSPF for that unit is 8.50, pretty sorry for such a high end heat pump.

2nd option: HSPF is 7.70, the minimum allowed by law. Even many builder 13 SEER units do better than that.

3rd option: HSPF of 9.50, finally some decent heating performance. But it should be for what you'll pay for that unit. And paying for SEER that won't save you much.

Keep looking...

Rheem/Ruud RPNL-037 with their Mod, HSPF 9.00 and it is a deluxe 13 SEER, drastically less bucks than the XP16 & XP17. Just an example.

[arc8]

Dave,

I'm wondering, was there a heat load calc done for your house? That would be my first step before determining sizing of equipment, type of equipment, and duct sizing.
I prefer two stage equipment whenever possible, but for me it depends on duct system and the heat load calc.

Don't believe those that say HP can't work in the Northern States and be efficient and last.

Best of luck.

[Tjune54]

I think the model heat pumps you listed are all two stage.

[RyanHughes]

I think the model heat pumps you listed are all two stage.

All but the XP17.

What is the exact coil model number they intend to install, if you know it? That will help tell you the matchup ratings for your particular combination, although BaldLoonie gave you the typical HSPF ratings of each HP model. Could vary slightly depending on which indoor coil is installed.

[Dave2425]

All but the XP17.

What is the exact coil model number they intend to install, if you know it? That will help tell you the matchup ratings for your particular combination, although BaldLoonie gave you the typical HSPF ratings of each HP model. Could vary slightly depending on which indoor coil is installed.

I've requested the model number from the dealer.

[Dave2425]

Keep looking...

Keep looking...

Rheem/Ruud RPNL-037 with their Mod, HSPF 9.00 and it is a deluxe 13 SEER, drastically less bucks than the XP16 & XP17. Just an example.

I'm trying. Unfortunately my calls haven't been returned.

I did get two quotes from the Trane rep for a XV95/XL16i and XV95/XL15i but they were about the same as Option 3.

[George2]

Did I read your model #'s correctly regarding the original equipment sizes?

The furnace is a 75,000 btu and the A/C is a 2.5 ton?

I can understand increasing the btus of the HP (for the heating btus), but why enlarge the furnace btus?

[BaldLoonie]

Bigger is better, George. Hadn't you learned that by now! If 75K 90% did the job all these years, then 90K 98% HAS to be better Going to a 3 ton pump over a 2.5 ton lowers the balance point a hair but not by what most would think.

I wouldn't want a 16i Trane, heating capacity is weak. Rather have the 15i, it gets 9 HSPF with the right coil. Sure beats the 7.7 of the Lennox XP16

[George2]

B.L.

Dave........I just re-read ur original thread and you stated that the serviceman said ur inducer motor was going bad?

Is it making noises or getting too hot? What did he say was the problem with it?

[54regcab]

With the cost of propane vs. electric I'd forget the furnace and use electric for backup/aux heat. Your electric is cheap compared to propane costs. No buying an expensive furnace and you can run the heat pump with electric backup at the same time.

[Dave2425]

I'm trying. Unfortunately my calls haven't been returned.

I did get two quotes from the Trane rep for a XV95/XL16i and XV95/XL15i but they were about the same as Option 3.

The Trane dealer followed up today with a quote for a XC95m/XL20i system. It was about 65% higher than option 1, 33% higher than Option 3.

[Dave2425]

B.L.

Dave........I just re-read ur original thread and you stated that the serviceman said ur inducer motor was going bad?

Is it making noises or getting too hot? What did he say was the problem with it?

He said it's making a noise when starting up and that usually means that it's going to fail sooner rather than later.

[George2]

He said it's making a noise when starting up and that usually means that it's going to fail sooner rather than later.

Have you listened to the inducer start? I would make sure it's not a slight vibration or out of adjustment.

[Dave2425]

I would not go with an air to air HP in N.D. If you can wait, I would install a split geo-thermal system.

IMHO........

Geo would be great if affordable. Otherwise I'd sure have an air source if I had LP heat.

I hadn't really thought about a geothermal system. I'll likely call my utility company to see if there are any local installers. The nearest ones I can find online or in the phone book aren't very close.

In the year that we've owned the house, our propane cost (includes hot water heater) averaged $95/mo and the electric was $80/mo. I plan to replace our current water heater with a Marathon model if/when we get rural water installed. I'll likely hook that up to our electric company's off-peak program. If I do that, rates will be $0.044 per KWH with a $5/mo controller charge.

I guess I just need to get a quote and see what the payback time frame looks like.

[54regcab]

What times are off peak with your local utility? In our area only summer is eligible for TOU pricing.

[Dave2425]

What times are off peak with your local utility? In our area only summer is eligible for TOU pricing.

There aren't any set times. It's all based off of system load.

[Mrak]

This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

You can find the rules for posting and qualifications here.

Additional infractions may result in loss of posting privileges.

[54regcab]

I screwed up and hit the wrong button and my last comments went to "la..la.." land. But I was just guessing that you will probably have a heat pump with a 2nd stage heat with propane or natural gas? I thought N.D. got colder than what a heat pump can effectively heat. Maybe not. 45 degrees is a pretty warm winter, perhaps I should consider moving to N.D.

I think it's a very good idea to get as much efficiency as you can. So a 2 stage compressor, highest seer you can afford, variable speed fans and any bells and whistles that you can afford. The Wi-Fi T-stat may be unnecessary but it's something I would like.

I can't really suggest any particular brands. I'm more in industrial service and not so much involved with residential but I'm grateful for the research you've done since I'm trying to decide which unit I should buy when I finally replace my hvac that I've had since 1977. Good luck.
Mark

In most areas the payback time on high end equipment exceeds it's lifespan. You go to 15 SEER for energy savings, the 2 stage stuff is more for comfort than saving money on utility bills. 2 stage equipment is almost always oversized, killing any real world savings that would have been achieved by the higher SEER ratings.