The most important thing is to feel comfortable with the dealer you chose to complete the installation. When they come to quote you systems, it's important that 1. they determine the correct size equipment for your home and 2. they determine that the ductwork you have in place can handle this much heating/cooling - if not, what needs to be done. How much total square feet are heated/cooled by your forced air system? Sounds like 1100 + 1000 in the basement from your post. The fact that your 4 ton (presumably) unit has done the job and lasted 20 years is a good sign that it may be the correct size. As for brands, many brands have good equipment on the market today, and it is all similar with regards to features and reliability. I personally would seek estimates on Trane, Lennox, or Carrier, but these are not the only solid brands on the market (Rheem, York also). A 2-stage furnace is a good idea, and you may also want to look into a 2-stage air conditioner.

Hope this helps. Post back with any other questions/updates. By the way, does your username suggest that you have 3 boxers? I have 2 - great dogs, but they can be a handful!

get some phone quotes from various local installers.
If your electric is inexpensive and you want to have a fancy system upgrade your A/C to a heatpump then you have dual fuel. New equipment will save in energy for sure.

Thanks for the info! The first company came and gave me an estimate - a 2 stage 95% efficiency heater and a 3 ton variable speed (?) 16 SEER air system from Whirlpool - plus I need a new something or other in the chimney (it's a city code requirement now) and to replace one duct that leads from the main furnace - $8,750 which I thought sounded pretty good. We heat from the forced air furnace about 2100 square feet, the other is on the slab and has baseboard heat. The rep did say that our A/C coils are original to the house - that only the compressor outside is newer (20 years?) and he thinks that they upgraded to a 4 ton compressor unit outide but didn't replace the original inside which he says is part of the problem. Regarding the boxers - now I have two, my oldest boy passed away in late 2008. I now have two boxers (boy 7 and girl 11) and a great dane who is under a year. So maybe I should change my log in name! Thank you!

Let us know how the other estimates go. I would get at least one more. The equipment quoted is nice, and I'm sure it has a good warranty, but there's nothing special about the $8,750 price quote. You can look into Trane or Carrier's communicating Infinity system, and it would likely cost about the same. Most important thing is to find a dealer you're comfortable with -- seems you felt okay about this one. Good that he's addressing any ductwork issues.

Well I had the second salesman come today (he was supposed to come yesterday but had a family emergency). The first contractor went around my entire house and measured everything - he even went up in the attic to look at the insulation. He measured doors, windows, asked me about hot and cold spots, how many people lived in the house, what temperature we liked, etc. Then he plugged everything in to an IPAD to come up with the system he recommended. The whole visit took about 3 hours and included in the price he gave me was a liner thing for the chimney which the city I live in now requires (that was $875). The second contractor who came today took less than an hour, and he didn't do any measuring or even go anywhere but down to look at my existing equipment. He told me my heater was an okay size but my air conditioner was a little too big. Then he gave me two quotes, one for a Trane 80%, 100,0000 BTU Furnace and a 3.5 ton 13 SEER a/c; the second was for a Trane 93%, 100,000 BTU Furnace and a 3.5 ton 15 SEER, priced $7000 and $9790.... He didn't write down anywhere whether it's a two stage heater or variable speed a/c and I didn't even think to ask. Also he never mentioned the liner for the chimney or the duct that needs to be replaced, so I guess I would need to add those two costs on to his estimate. At this point, I think I'm going to go with the first contractor since I think he was much more thorough. On the flip side, I've never heard of Whirlpool HVAC equipment and Trane is well known and has a good reputation.

I fully agree with your reasoning. The first contractor did things that are signs of a good, experienced company. Of course it doesn't say much of the installers who will be doing the work, but it certainly bodes well for the company as a whole.

I'm not an expert on Whirlpool equipment, but I did a little research and it sure looks like an Amana (made by Goodman) product with Whirlpool labeling. It has a very good warranty. If you do research you will find more negative opinions of Goodman than positive ones. My opinion is that most equipment today is very similar, and the installer makes the difference. With this said, Amana/Goodman would not be my first choice for a system going in my home.

I'm not sure if Whirlpool equipment is made differently in some way, and I hope Baldloonie sees this post and comments since he knows the different brands inside and out, but it looks exactly like Amana/Goodman equipment and likely is. You may want to check if the first dealer offers any other brands.

I would definitely choose the first contractor, and wouldn't let the equipment brand be a deal breaker, but I'd also look into other brands with this dealer.

I called the salesman and left him a message to ask about giving me a quote for another brand. Meanwhile I got a message from another person at the same company who said that Delaware has a new program - some Energy conservation program and that they are working with the state to get the software to do an energy audit. They would do that before installation and then after, if there is more than a 20% energy reduction (which he thinks there will be) I will get $$ back from the state. The bigger the reduction, the bigger the refund and I could potentially get back $3000. So I called the second company and asked them about it and they said that it wasn't worth it because they do not do energy audits and I'd have to pay an outside company. So they blew me off basically. I will wait to hear back from the salesman to see if he will give me a quote on another brand or if Whirlpool is my only option with them....