This is a great posting. I love the picture of the house. The floor plan is very helpful.

My first reaction is the heat pump and furnace seemed over sized. I realize the insulation is not up to current standards and you have have single pane windows. How were the load calcualtions done? Did the contractors use a software program and entered measurements of your house? I find it hard to imagine you will need a 100K 96.7% efficiency furnace for the first floor, plus another 2 ton heat pump for the second floor to keep you warm in the mild winters of Alabama.

It seems connecting to the gas line will be fairly inexpensive. I recommend going with a properly sized gas furnace. I imagine the electric rates in Alabama are much lower than what I pay in NJ. The hybrid dual fuel option might be a good investment for the first floor. Find out how much extra the heat pump versus AC will add to the price. Having a heat pump with a 96%+ furnace is a little over kill.

Will the second floor heat pump be installed in the attic? Your second floor is 700 square feet. A second unit for the upper floor is nice to have, but expensive. Have you investigated running ducts from the basement up to the second floor and adding zoning?

I would personally have rigid ducts wherever possible. The prices you quoted seem reasonable, but it is difficult to tell due to the duct installation.

I'm rather surprised to hear that our tonnage may be oversized. Three guys calculated 3.5 ton for downstairs and one guy said 3 ton, but everyone says 2 for upstairs. I did forget to mention that the current 700 sq ft isn't including the remodel; we will be recapturing some knee wall space for closets and a bathroom, and the unfinished room (to become the MBR) has a vaulted ceiling.

The last guy (Carrier quote) had a detailed computer estimate of tonnage based on windows, ceiling height, cardinal directions, etc. It calculated exactly where we needed ducts and how much CFM.

Around here, everyone seems to put a separate unit for the upstairs (always a heat pump). We've had an historic bungalow in Arkansas with just one gas system and it was never comfortable upstairs; we had to add window units just to stay cool, even on the north side of the house! I did ask one or two contractors about it here, but no one recommended a single system.

The specs above should be for a 93% furnace, but he told me the Infinity 96% is only a dollar more for him, so we could get that one instead. We have to stay with a higher efficiency furnace for the basement because the air handler must be hung horizontally due to our space issues; venting becomes a problem unless we do at least a 90% furnace.

Straight AC (instead of heat pump) with the same furnace on the downstairs system would save around $500. So that brings his quote for Carrier and all metal ducts to nearly the same price as everyone else for Rheem heat pumps with some flex duct. I think for the price, we would stay with the heat pump (electric rates are pretty low in the South, so we would benefit a good part of the year).

Any feedback on Carrier overall? Or on hybrids? I can't see any downside, except the small hassle of having the utility company come dig the line and having to switch over our water heater and range (and the utility company gives us a free 40 gallon NG water heater to boot)!

If you are convinced the contractor has done a detailed load estimate, then go with his numbers. My comments on the sizes were based on floor area. Area estimates can be deceiving.

Having a separate units for upstairs and downstairs is the best for comfort. This is what I have in my home.

I have Carrier Infinity furnaces. I recommend getting this furnace if the contractor is going to give it to you for the same price. I also recommend getting the Infinity controller. Ask the contractor about this.

Is the contractor offering the Carrier rebate? The combination of the heat pump you listed, the Infinity furnace and controller qualifies for a $500 rebate. If you upgrade to a 2 stage Infinity heat pump the rebate would be $1100. However 2 stage heat pumps only come in whole ton sizes so you would have to get the 4 ton unit.

Carrier has a very good reputation. Several years ago their furnace had problems with the heat exchangers but it appears this has been solved. My 25 year old Carrier furnaces were still working with few problems when I replaced them. This was the main reason I stayed with Carrier. Rheem is also good equipment. I am surprised you heard negative comments.

You can also purchase a 10 year labor warranty from Carrier. Ask the contractor to quote this.

I'm glad to hear you like the Carrier Infinity. I'll have to check about the controller; I know he said something about it using the Infinity Control when he mentioned that the furnace barely cost anything more than the Performance 93, but I don't know if it's included in the price.

I don't know anything about a Carrier rebate. I tried to search Google for it, but I can't find any existing promotions. Maybe he already took that into account for the quote. Is it something I would have to file after the fact, not a discount he would take off in advance? How do you look up what combination qualifies for what rebate?

We heard the Rheem units had problems with the new refrigerant, apparently the fans weren't right and resulted in rusted coils, or something. Several contractors have mentioned this. Is it not a current issue?

The Infinity furnace with the controller is one of the best furnaces avaialble. I am confident you will be happy with it.

The Carrier rebates start March 1. The start date sometime vary by region. The purchase needs to be made after the start date. I was able to find the rebate matrix via a Google search. Below is a link.

What filter has the contractor proposed? I recommend a 4 inch media filter. It will perform much better than a 1 inch filter and last 6 - 12 months.

I am not a Rheem expert and have not read about any major issues.

Here is a link that might be useful: Carrier Spring Rebate Matrix

Equest

I will take a contrary view. Correct sizing of HVAC and good ductwork system including adequate returns is important. Ask for R8 insulation.

For your area/climate, the downstairs system is overkill.

I assume you plan on pursuing the nat gas connection to your home.

A 96% efficient furnace paired with a high end HP for Alabama location?

And the upstairs system is Carrier low end base series. I would want at least the Comfort Series paired with a var speed air handler and a 9 KW
prewired heat strip that operates in 3 KW increments. Then a Carrier thermidistat for handling summer humidity.

And BTW, that is not an Infinity Furnace. it is a relatively new Carrier Furnace called Performance 96 Two Stage. See link.

IMO

Here is a link that might be useful: Performance 96 Two Stage

How much is your total cost for electricity? How much would gas be and the monthly service fee? In a climate like yours I would not think that a gas furnace is necessary. I would think a heatpump would handle everything very efficiently most of the time. The gas could come in handy for hot-water and cooking and the rare extra cold days for your climate.

And is this northern AL or southern? Much less likely to get snow in Mobile than Muscle Shoals.

Mike, thank you so much for your feedback and the rebate link. I will definitely ask about it. I have heard good things about the Carrier Infinity system, but can you tell me what is so special about the controller? I know it has some diagnostic capabilities, but is that the big difference?

Tigerdunes, thanks for your input. I know the furnace model I posted isn't an Infinity; it was the first one he quoted me, but in talking later, he said the Infinity only cost $1 more in his price book, so we could upgrade to it if we wanted. I don't have the model number for it, but I'll ask next time I talk to him.

Where are you recommending the R8? We are planning on R13 fiberglass batting for the roof rafter bays, because we are limited by the stud depth. We are planning to fur down with 2x2s to gain enough room for the fiberglass. We looked into spray foam, but it's out of our budget.

I've always understood that the new hybrid units are a great choice in efficiency and energy savings, even in the South. We don't know how long we will be in this house (we love it, but we've never lived any place more than 4 years, so I have to look at history), so we weren't planning on lots of upgrades. But at this price, we can have it for not much more than the bare bones.

I do see what you are saying about the upstairs system versus the downstairs. I will ask about the cost difference to do a 14 seer heat pump up there. Is there any other upgrade you think would be justified for the top story?

Neohio, we have propane right now for hot water, range, and wall heaters. We were paying $2.49/gallon, but it will be going to $2.89 for the year starting next month. Natural gas would be $1.23 for the equivalent gallon (it's priced per cubic foot, but she gave me this number for comparison), with a $7-something monthly charge. We pay a base service fee of $22.11 per month for electric, plus $.088/per kilowatt based on usage.

Because we don't currently have central heat and air, it's very hard to determine what our utilities will be and what system would be best. Our winters are mild, but we have been pretty cold in the farmhouse unless we close off interior rooms and run the 25,000 btu propane wall heater (serves the living and dining room), a large electric heater (for the kitchen), and a 10,000 btu propane heater for the bedroom. All the other rooms, upstairs and down, are unheated and cold! In the summer, we had three window units in about the same places (main living area, kitchen, and one downstairs bedroom), and could stay comfortable. But upstairs, with no AC and little insulation, was miserable!

The Infinity controller will intelligently control the stages of the furnace and speed of the variable speed blower. It will do other things like tell you when it is time to change the filter and alert you if a fault has been detected. It will also manage when the furnace and heat pump should operate based on the outside temperature.

I agree with Tigerdunes about the upstairs heat pump. It is a builder's grade model and should be upgraded.

What would you recommend for upstairs? Would moving to 14 seer be enough of an upgrade, or do you have something else in mind? We can't really go much over the $14,000, so would it be better to back off some features on the downstairs and apply that money to the upstairs? Would going to an 80,000 btu furnace downstairs save us much money? I could ask about the 92% furnace instead of the 96%, but I know the price difference between the 93.3% and the 96% was only $1, so I don't know if it would save us anything.

One thing I'm unclear on is how much the upgraded humidity control on the downstairs Carrier Infinity will help the upstairs. Our central foyer and staircase are fairly open and the upstairs air return is slated to be in the ceiling of the hall, just over from the staircase. Will the humid air fall and get captured by the downstairs system, or will it be almost like a closed loop? I know any AC will dehumidify, but the HVAC contractor said the upgraded Carrier system will control humidity in any mode, not just AC, and seemed to emphasize that was very important in our climate.

Foyer and staircase (a work in progress!):

Right now, we only live downstairs essentially. With a MBR/BA remodel, we would be upstairs in the early mornings, late evenings, and at night. We don't have kids, and the main guest room will be downstairs, so the other two rooms will be extra guest rooms and/or my craft space. With that in mind, we are trying to determine how best to divide the funds we have.

For upstairs get a quote for the Comfort or Performance series heat pump. This is better built equipment and usually more efficient. If you do move up to a two stage heat pump, then the air handler needs to be upgraded to a variable speed model. This may go beyond your budget, but it is worth a discussion with the contractor.

You don't need a heat pump for downstairs. It is overkill when paired with a 92%+ furnace. You will be very warm in the winter with the furnace. In addition you may never see a pay back by operating the heat pump. Going to the next smaller furnace usually is not a big savings in cost. I do think an 80K BTU furnace at 95% efficiency is the correct size for house. Review the load calculations again with the contractor. Don't let him over size the furnace.

The Infinity controller will be a big help in reducing the humidity in the summer. I have achieved a humidity level of 38% in August in my house. This allows me to set the temperature at 79-80 degrees and still be comfortable. I imagine it gets very humid in Alabama during the summer.

The controller can't change the humidity unless you add a humidifier. Your house problably has a lot of air infiltration, so I suspect low humidity in winter could be a problem. You can wait until next winter to add the humidifier. Just let your contractor know about your future plans so it can be factored into the installation.