You are in an all electric situation?...location please?...Size of your home?...Size of system to be replaced?...price includes all ductwork modifications?...how will return air be filtered?...new lineset or reuse old?...that's a 15 KW heat strip?...will it be staged?...any other quotes to be solicited?

post back

IMO

Hi, I posted a few weeks back, existing TRane 90% efficiency furnace / propane gas heat with air con unit, 25 years old, area this unit serves around 3500 square feet (currently not zoned). Would like to go to electric because we are on a rural electric coop (less expensive kw) and plan to put in a solar array and want to maximize the savings from that. Also, our propane has gone up considerably over the past five years. We are in central Georgia, average low temps in winter mostly in low 40s, average high temps in summer high 80's to about 92.

I got estimates on a dual fuel system with backup propane furnace and decided not to go that way. These three estimates are from a single contractor and I am wondering which one has the best potential for energy savings.

previous thread: http://ths.gardenweb.com/discussions/3499675/opinions-needed-replacing-trane-forced-air-90-furnace?n=39

Again, size of heat strip?...staged or not?...cost if any to modify electric service panel for heat strip?...what does dealer say about electric service?...new lineset or reuse old?...how will return air be filtered?...quotes include all ductwork modifications?...

IMO

I going to assume option 3 is their XL16, not XL18.

Any reason why option 3 is not zoned?

Between 1 and 2, there is only 1 point of SEER for $800. Might not be worth it based on your electric rates.

It would be difficult to give an accurate prediction of what your savings will be, but I'll make a wild guess or two.

In your last thread, you stated that you spent $700/mo on your electric bill. That I guess was with two systems, a 3-ton and a 5-ton. You have other things going on with your property, so lets say that $400 was for the old 5-ton system. Let us also assume that the old system, being 25 years old, was around 8 SEER. A rule of thumb for guesstimating savings is that each point difference of SEER is a %4 savings. So going to 16 SEER would be 8 * 4 = %32. Going to 18 SEER would be %40 and 20 SEER would be %48. So you save $128 for option 3, $160 for option 2 and $192 for option 1. Going from 16 SEER to 18 SEER saves you $32/month for a cost of $2215. It would take you 69 months to break even or recover that money spent. If you run the cooling for 7 months a year, that is nearly 10 years to break even. Option 1 saves $64/mo for a cost of $3016 or 47 months ( about 7 years) to break even.

Wild guesses and may have nothing to do with reality.

The bids include ductwork.

Filter is my choice of Perfect fit media filter @ $250 or Clean Effects filter @ $700 (add on to price).

Have sent contractor an email about line set and size of heat strip / staged or not, waiting to hear back.

electrical work needed for heat strips $1120. We would probsbly have this done anyway for various reasons.

I would not have the Clean Effects. Go with Trane Perfect Fit Media cabinet.

here are the AHRI numbers on option 1 and 2.

6749945 Active Systems TRANE XV20I TRANE 4TWV0060A1 *AM8C0C60V51 1450 830 675 54500 12.70 19.00 51500 10.00 48000 1 HRCU-A-CB Yes 364 1048 Yes

6750462 Active Systems TRANE XV18I TRANE 4TWV8060A1 *AM8C0C60V51 1450 830 675 54000 12.50 18.00 50500 10.00 48000 1 HRCU-A-CB Yes 381 1027 Yes

go with XV18i.

if 15 KW heat strip size, not certain that is large enough. Only 50 KBTUs. Definitely you want it staged.

IMO

Heard back from contractor, to wit:

new lineset

15 kw strip heater, yes staged

i asked him if he has any worries 15 kw is on the small side

At 17 degrees F the heat pump puts out 48K BTUs. If the heat strip generates 50K BTUs, it would seem 98K BTUs would be adequate. Winter design temperature for Georgia is in the low to mid 20s.

Did anyone do a load calculation? Are big are the return filters?

for mike, 50 K might be low for a condenser breakdown...that's where I was coming from... but even at that the occupants might be uncomfortable but they won't freeze... plus one other issue to take into consideration is that 50 K might not be enough to properly temper air on a defrost call...

IMO

Good point. I forget that heat pumps have to run defrost cycles.

So, I asked the contractor about the 15 kW heat strips, as a different one Ihad recommended 20 kW ones and there was also a question here whether or not that would be enough, and he declined to take the job, saying I questioned his professional judgment and he could not work for anyone like that because he is a Christian businessman, and his business was founded on Christian principles and he was honest, etc.

i kind of feel that I dodged a bullet with that one. Problem is, he is the only person within 30 min of our house who has experience with the Trane 900 series computerized thermostats which are required for variable speed heat units.

Do I go beyond the reasonable distance (45 min to an hour) to look for an installaer for a system that no one local will be able to service? Or do I step back to a two stage system that would be easier for our local companies to service?

Btw, the electrical work (basement panel upgrade) was completed early this week for a cost of $1120. This was something we should have done in early 2014 when we went from 200 amp service to 400 amps so it was not solely for the purpose of switching from a flags furnace to a heat hump, and I am not really including it in the overall cost of this project.

Still hoping for opinions on this choice between out of town vs local contractor.....

Are you removing the propane tank from your house? if not, I am curious why you decided not to use propane as your back up heat source.

Is the local guy a Trane dealer? If he is, then he should know how to install an XV18i heat pump. Some one who is not knowledgeable about Trane products can also improperly install a 2-stage heat pump. We see it on this forum all the time.

I recommend you widen your search for competent Trane dealer. Larger companies tend to have bigger coverage areas. You might fall into it. See if there any nearby American Standard dealers, they sell the same equipment. You could also look into the Carrier Greenspeed heat pump as another option.

No, we are not getting rid of the propane tank. We still need it for three fireplaces, a water heater and outdoor grill. But our intention is to put a solar array on the roof, which would offset electricity but not propane (obviously).

The local guy is not a Trane dealer so he is limited as to the type of equipment he can buy from them.

I still think it makes sense to get a dual fuel system with a propane back up. Upgrading to 400 amp service means you use a lot of electricity. The solar panels can provide the electricity for your other appliances. Solar does not work at night when you are most likely to be using the backup.

Our service was already 400 amps. The electrician "moved" 125 amps to the subpanel in the basement.

Good point about the backup furnace being on at night, not benefiting from any solar electrical gain. However, the cost of propane has risen again already and I dislike being held hostage to that particular commodity. The cost of the backup gas furnace was at least $1000 more and who knows if it will be cheaper?

Are you sure you need a 5-Ton heat pump?

http://www.loadcalc.net/ Do not oversize!

I don't understand why a furnace equivalent to the air handler would be $1000 more. That doesn't sound right. Burning propane is still going to be cheaper than burning electricity, It should also be more comfortable.

You could buy your own propane tank and then shop for the lowest prices.

We own a 1000 gallon buried propane tank.

M: in his previous thread, he gave his propane and electrical costs. Electricity was far cheaper in his case.

I went back to the first post for the numbers:

Cost per 100,000 btu of useable heat
Electric baseboard:$2.64

Heat pump:$1.07

Propane:$2.30

The backup heat strip is the same cost as baseboard heat. They both operate as resistance heat. It is a little more expensive than propane. If you think propane prices are going up, and it costs an additional $1000 to get a furnace then the heat strips are the right choice.

I have to keep reminding myself you are paying 50% less for electricity than I am, and your propane cost are much more expensive than my natural gas costs.