I think a modulating furnace is foolish in a DF system, especially when taking in the added cost of upcharge plus the fact you are generating some electricity from your solar install.

Any idea how many KWHs are generated on average in the winter months?

Of course any of these systems will require the ubiquitous Infinity controller, best matching ALA Carrier evap coil, and a filter box. Maybe new lineset as well.

IMO

Tigerdunes, here's our production and usage for the last year. Winter months can fluctuate year to year depending on snow covering the panels.

Production - kWh

11/13 - 446
12/13 - 265
1/14 - 313
2/14 - 375
3/14 - 849
4/14 - 794
5/14 - 995
6/14 - 1065
7/14 - 939
8/14 - 904
9/14 - 908
10/14 - 603

Total produced - 8456

Usage - kilowatt hours metered

11/13 - 623
12/13 - 843
1/14 - 618
2/14 - 712
3/14 - 561
4/14 - 314 (credit $45 from selling excess)
5/14 - 437
6/14 - 1127
7/14 - 484
8/14 - 716
9/14 - 439 (credit $46 from selling excess)
10/14 - 486
11/14 - 687

Total 8047

That's not a lot of excess KWHs to apply to heat pump usage. I would get a price on the modulating furnace with a high eff AC condenser. What's the upcharge to the heat pump from similar model AC condenser?

You have several options to carefully consider.

IMO

Each credit (April/September) was for around 1000 kWh. So total for last year there was an excess of around 2500 kWh.

Is that still not a lot of excess?

I guess I am not following your numbers. Perhaps you can better explain.

Your lowest production is in the winter months and that's when you need it most to offset HP usage.

What is your electric rate? What is your nat gas rate?

Post back.

IMO

What is the gas rate? What is the cost if you have to buy additional electricity? Get the cost of the therm and KWH, don't add the upfront service charges.

Tigerdunes,

I'll see about getting the rates later today when I get home.

What happens in terms of solar is that you banks any unused kWh you produce each month. The electric company pays us a credit once that banked hours go over 1000.

So in the summer we tend to make a lot more electricity then we use so we are able to bank the extra. At the end of April we had 1000+ kWh banked and the electric company paid us $45 for the extra. Same thing happened at the end of September.

So the electric company paid us $91 for the extra electricity we produced over the last years. That's why I posted that we out produced our usage by around 2500 kWh in the past year.

1000 - got paid $45 in April
1000 - got paid $46 in September
500 - Difference from what is currently banks vs usage.

Yes, we will produce less electricity i the winter months when the HP will run but that cost will also be offset by the amount that we are able to bank and/or get paid for over the better producing months.

Hope I explained it OK.

I also emails the guy who gave me the HP quote and he sent over a quote for just the variable speed furnace, humidifier, and high efficiency 2 stage AC.

Cost difference was around $2500 for 2 zones.

59MN7080 furnaces with 25VNA8 heat pump condensers - came in around $19500 after rebates

59MN7080V21-20 modulating variable speed furnaces, humidifiers and 24ANB736 - came in around $17k

Mike,

Assuming I did the math correct.

Per therm - .927 (last bill was 183.2 therms for 169.95)

Cost if we needed to buy electric - .138 (625 kilowatt billed for 86.50)

Using your rates, to be used as a guide only.

97% eff for mod furnace
3.75 COP for HP eff

Cost per 100,000 btu of useable heat

Electric baseboard: $3.64
Heat pump: $1.08
Natural gas: $0.93

You will have to decide the impact of your solar production and if high end heat pump is worth it. I would go with high eff modulating furnace with high eff AC condenser and let the solar system cover your home's electric demand. Keep in mind these Greenspeed HPs still have issues about noise. I was just reading about Trane XV18 having a noise issue.

IMO

If you did get a heat pump instead of just an AC condenser, it does not have to be a Greenspeed. An Infinity or Performance 2-speed model should be fine for your set up. It should be about a $2000 savings.

The Greenspeed is great for very cold climates and when it is going to paired with back up resistance heat. I think it is overkill in your situation.

The only thing to consider is the life expectancy of a heat pump is short than an AC condenser.

Thanks guys. We have a lot to bounce around this weekend. All the information you guys provided will help in our decision.

Mike, we are not all that concerned with life expectancy of the pump as we are looking mainly only 7-10 years down the road. We are planning that we'll move when we retire. This install is mainly for 2 reasons. 1 - so we get some of the savings after it is installed 2 - Our current system is 15 years old and others in our development are starting to have problems so we are trying to be proactive and 3 - so that we can distinguish our home from others in the development (82 homes with most being a variation of 5-6 basic types) when we are ready to sell.

We have been thinking that if we go the heat pump route (along with the solar) it could be a selling point to make our house more desirable than some of the others in the area if/when we are ready to move.Now we'll also take into consideration the fact that it doesn't have to be a heat pump setup.

Poor logic...the modulating furnace with AC is the way to go. And you will be better served when trying to sell your home down the road.

IMO

I think the solar energy is a big plus in selling your home. I would be curious how much a realtor thinks it will add to the asking price compared with a similar house.

I personally don't think you will get your money back if you spend the extra money on a heat pump. I think you should go with a the modulation gas furnace and a 2-speed AC and have the utility company pay you for excess electricity. It is cheaper to heat with gas so why not just pocket the excess electricity charges?