Input on Heat Pump System

[cold55]

Hi there. I'm about to purchase an air heat pump to replace my propane furnace which runs me $350-$400 a month to operate during the winter. My house is about 2,900 sqft with vaulted ceiling. I'm hoping to reduce my heating cost; hopefully by half. I don't even know if this is even possible. I currently have a 17 years old 80% afue propane furnace. I'm told based on the age of this furnace that it may be operating at less than 70%.

Anyway, I'm seriously considering a heat pump with the following specs. What do you think?

Lennox XP17 3.5 Ton Heat Pump
Lennox SL280 Variable Speed 2 Stage Propane Furnace
Honeywell 7 Day IAQ Duel Fuel Thermostat
Honeywell F100 Media Filter & Cabinet (MERV 12)

Is this a good system or should I consider the 95% G61V or the SLP98V instead? Does it make sense to go with higher efficiency since the furnace is just a backup?

Or would just replacing the existing system with just the SLP98V be a better/cheaper option? The summer does not get very hot here that I would really need an AC; good to have but not required.

Thanks!

[BaldLoonie]

How cold you get in the winter? If you are somewhere that rarely gets below freezing, the 80% should be fine and rarely on. If you are like us and spend a lot of time in furnace temps, going to the 95% would make more sense.

[NCHeat]

where are you located? How often are the winter temps 10-20F? Many dual fuel systems use the HP in the spring and fall and the gas/propane a good amount in the winter?

[cold55]

That makes sense. I'm in Seattle area.

Do you think going the heat pump route is a good idea or is it better to get a SLP98V furnace for 50% less than the heat pump system?

[tedkidd]

Hybrid heat all the way. Energy cost insurance.

High efficiency SEALED COMBUSTION equipment, unless you are a renter's mindset.

Energy is like rent, efficiency is like capital. You can own efficiency, can't own energy (unless you get solar or wind).

And unless you have a crystal ball, you can't know what future energy costs will be. I've never met anyone who wished they got crappier equipment, met many who wished they hadn't been shortsighted when they made equipment decisions...

[BaldLoonie]

I'd guess you rarely will spend much time with the gas running up there so 80% is probably a wise move.

[tedkidd]

For a lot of ancillary reasons I don't like anything that requires a chimney. Chimney's cost hidden money, not just the efficiency drop.

I've replace equipment only, no weatherization, and by doing the jump from 80% to 95% seen nearly 30% decrease in energy cost.

Get rid of all big holes in your house. The chimney is one of them. When it comes to condensing v/s non-condensing, the short money saved is not worth the long money lost imo.

[cold55]

It’s unfortunate that we can’t talk about price since that would be the real determining factor. But can we talk in cost difference? In Seattle, as BaldLoonie mentioned, the furnace would be rarely used. With the furnace in the garage, any retrofitting of the vent/chimney will most likely not affect anything right? If so, it comes back to initial investment and payback period. So does this SLP98V cost few hundred more dollars to install than the SL280 or am I looking at couple of thousand?

[garya505]

Don't forget that with a 95% you need a furnace condensate drain that is not exposed to freezing temperatures. Sometimes this is easy, but sometimes it's a pain-in-the-a**. Do you have a floor drain or laundry drain in your garage?

[big sky hvac]

It’s unfortunate that we can’t talk about price since that would be the real determining factor. But can we talk in cost difference? In Seattle, as BaldLoonie mentioned, the furnace would be rarely used. With the furnace in the garage, any retrofitting of the vent/chimney will most likely not affect anything right? If so, it comes back to initial investment and payback period. So does this SLP98V cost few hundred more dollars to install than the SL280 or am I looking at couple of thousand?

The SLP98V is going to cost more than "a few hundred" dollars over the SL280. You're going from an 80% furnace to a 95% modulating furnace. If you're looking to save some money on your purchase, here are a couple of ideas. You can go with a G61MP furnace(2-stage, 95% w/psc motor) and a lower seer heat pump. You could go with an XP14 heat pump and save yourself a little money there too. It really depends on your budget and how long you plan on living in your home. If you're staying in the home 5-10 years or longer, you should see a ROI by going with a 90%+ furnace. It just depends on your budget and how much you're willing to spend. I really like the SLP98V furnaces, I've got one for my house, but they're higher end and not for everyone's budget.

[BaldLoonie]

Looking at a temp chart for Seattle, looked like there was a cold spell something like end of Feb where some overnight lows were cold enough to have a gas backup on. Otherwise, the rest of the year you'd be on heat pump. Or if you don't keep it that warm inside you might get by on heat pump down to 20 or 25 and almost NEVER need gas. So saving $5-10 a month on gas with the 95% would pay in 40 or 50 years!

[garya505]

Looking at a temp chart for Seattle, looked like there was a cold spell something like end of Feb where some overnight lows were cold enough to have a gas backup on. Otherwise, the rest of the year you'd be on heat pump. Or if you don't keep it that warm inside you might get by on heat pump down to 20 or 25 and almost NEVER need gas. So saving $5-10 a month on gas with the 95% would pay in 40 or 50 years!

Wouldn't the ROI on the XP17 over the XP14 also be long?

[BaldLoonie]

Well could be! Little cooling needs, probably more heating needs. Probably decent electric rates.

Depending upon furnace & coil, that HP is running 14.70 to 15.20 SEER (not 17) and 8.50 to 8.70 HSPF. Fairly low HSPF for a supposedly efficient unit. Some matches won't qualify for the tax credit eityher.

The XP14-042 runs about the same SEER and HIGHER HSPF around 9.00 so the ROI on the XP17 over the XP14 would be NEGATIVE!!!!!

Only way the 17 makes sense is if it is less money than the 14!

Good thinking, Gary!

[big sky hvac]

I won't disagree that in that winter climate, a 95% furnace will take a while to get any ROI. I wouldn't recommend putting an SLP98V in, but if you could go with a single stage 95% furnace for a little more than an 80% furnace, you might see some ROI. If the heat pump were to go down for a while, you might see some of the savings then. There may also be some rebates available through local utilities or the state. In MT, if you spend money on energy improvements to your home like windows, doors, siding, insulation or energy star appliances like furnaces and water heaters, you can get some tax credits to help offset the cost of the upgrade. Up here, if you spend a minimum of $2500 on energy improvements to your home, you'll get a $500 tax credit. If it's less than $2500, it gets prorated. The local utility offers $150 to go from an 80% furnace to a 90% furnace and $20 for installing a energy star rated t-stat. Add the $150 the federal govt. gives for a 95% furnace now, and you'll get back $820. A lot of times that'll pay for the upgrade and make it worth upgrading to 95%. With the lack of much of a cooling season, I don't see the benefit in a 17 seer unit either, I think the ROI on that would be a while too. :.02:

[tedkidd]

Looking at a temp chart for Seattle, looked like there was a cold spell something like end of Feb where some overnight lows were cold enough to have a gas backup on. Otherwise, the rest of the year you'd be on heat pump. Or if you don't keep it that warm inside you might get by on heat pump down to 20 or 25 and almost NEVER need gas. So saving $5-10 a month on gas with the 95% would pay in 40 or 50 years!

Again, the mirriad issues with non sealed combustion appliances should very easily justify doing away with them. If the don't because your climate is too mild, then justification of the furnace (and the myriad of health/safety/envelope issues) weds to be looked at. Just go straight heat pump.

Carriers new green speed is 13 hspf, what is economic balance point against low efficiency furnace, -20f?

[martyinlincoln]

Have them quote you a sl280 with a xp14 and a G61mpv with a xp14. They money you save by not getting a xp17 might well pay the cost difference between the 80% and 95% furnaces.

[tedkidd]

Have them quote a CBX40UHV Variable Speed Air Handler and XP21, Better airflow through an air handler than a furnace and much better efficiency.

Bag the furnace if it's not likely to provide any benefit. Your energy savings will pay the incremental expense, and you'll have a much nicer system.

If you had an audit done you could get solid cost/benefit helping you understand net monthly cost or savings of all these units against each other.