Regarding ductwork, do you know how many return air ducts you have? Since often times ductwork systems are undersized to begin with, I don't like the idea of increasing tonnage without ensuring the ductwork is in good condition and properly sized. However if the old system did a good job handling the the temperature throughout the house, it may be okay. An extra return may need to be added. The XP16 is a heat pump. I assume he meant XC16. The XC16 is a 2-stage unit, which can help control humidity better, but I would not use it without a furnace with a variable speed blower. It is the variable speed blower that is required to get more than 14 SEER in most cases. The XC15 is advertised as a very quiet unit, but that doesn't mean the XC16 will be loud (the brochures should have the dBa sound ratings). The Lennox guy should have given you model numbers. You'll want to talk to the Trane dealer about sizing to ensure 2.5 tons is sufficient. Did any of them do a load calculation to prove that you needed more capacity? You aren't comparing apples to apples with both quotes, since the Lennox furnace does not have a variable speed blower, which I'd recommend for greater efficiency and comfort. They can also overcome slightly deficient ductwork systems by adjusting their speed. If the ductwork is in very poor condition, however, they can be louder (I think you'd know if the ductwork was in poor condition/undersized, as you would have had symptoms with the old system, like uneven temperatures, noise, and lack of airflow).

To provide the info that you need, the contractors need to provide you with the coil model#. You do not need, or want, a mismatched coil with a new condenser. Model#s are the only way for you to know if you are getting a matched set. There are 3rd party coils that are rated by the American Refrigeration Institute (ARI) if you are not being supplied an OEM Trane or Carrier coil due to size limitations. You want an ARI-rated matched set. The "36" in the Trane model number means 3 tons. You will probably get no more than 13 SEER by using the blower in the original furnace, so getting any higher than a 13 SEER condenser is probably a waste of money, as far as efficiency goes. A 14 SEER (or higher) condenser may be quieter or offer other benefits, but not more efficient due to the old blower. Good luck.

First, any of the brands and models mentioned will give good service if they are sized correctly and properly installed. All hvac equipment makers use secondary parts from the same major suppliers, GE, White Rodgers, Robert Shaw, Fasco and Honeywell to mention a few. Despite all the hoopla none is makedly better than the others. There is no unit made that you can have installed and never have a problem. The great percentage of hvac problems occur in secondary equipment, such as relays, switches, motors, printed circuit control boards and other replacable parts. As I stated earlier these parts are produced by a few major firms who supply the same quality parts to everyone, they do not make a good part for one maker and a bad one for another. In each batch of say 500 parts a small number are going to fail, this is an irrefutable fact. Whether one gets a piece of equipment with one of these destined to fail parts depends on luck and nothing else, the name plate on the equipment has nothing to do with it. Be more concerned about the installation, any brand wrongly sized and poorly installed will not give good service. Next be concerned about the warranty, does it cover parts as well as labor and trip fees? Failure to get a clear understanding about warranty provisions can lead to nasty finiancial surprises later. Lastly consider price, get the best deal you can on the equipment you select, don,t be too concerned about the brand. Check out the contractor as thoroughly as you can. Good luck Iggie

There's much more to this equation than just what you may or may not save on utilities. A lot of this depends on your location and your local weather. How much you save on energy costs depends on a variety of factors like how much you are paying for electricity and how much you use your AC system during the summer. Some locations, such as mine (Katy, Texas area) can benefit by having a more energy efficient model. The devil is in the details of anything you choose. These details come down to proper sizing, humidity control, quieter operation, staging, manufacture support like warranty terms, installing contractor ability to repair if / when system breaks down. In my area it's not uncommon for payback of such systems to take 10-15 years. This also depends on what the new system is replacing, depends on use of the equipment etc. The other effect of all this is also feeling more comfortable in your home. A two or more staged system when sized and installed properly can be the best of both worlds. Another analogy is when you buy a car, you may buy it only for the gas mileage. But after you take a long trip in it you may wind up saying I wish I would have bought a more comfortable vehicle, my back is killing me and I have a cramp in my leg. Typically the only reason you buy a new (complete) HVAC system is the current one isn't providing you the comfort you want. Certainly changing a few parts or one piece of the system may get you down the road... but if you're planning on staying in your home... well this ramble just gives you a few more things to think about.