When purchasing a new Comfort System for your home there are many things to consider!
The first thing you want to make sure of is that you are getting a system that will take care of your needs. There is many different brands of equipment and types of systems on the market today. Investigate the different systems and euipment and ask questions and find a contractor you can trust. A good contractor can reccomend the type system he thinks will do best for your home based on several factors. 

That brings us to the contractor. No brand of equipment or type of system is any good at all, unless it is properly installed and maintained. The contractor you choose is actually more important than the equipment you choose. With that said, I would like to be your contractor, however there is many very good reputable contractors in the valley. I am sorry to say that there is also some who don't always have there customers interest at heart or may like to cut corners to get the price down or, well you get what I mean. This is where you need to check out who ever it is that you are thinking of installing a system. The best thing to do is ask for references and call them and ask them their opinion. You can also check to make sure they are licensed and insured and check with the Attorney Generals office or Better Business Bureau. It is your home and you deserve to have a first class comfort system installed correctly by someone who will stand behind there work. 

You need to make sure a heat loss, heat gain calculation is done on your home to make sure that your new system is sized correctly. Also your ductwork needs to be inspected to verify that it is sized properly and that it doesn't have any duct leaks.

One thing to pay attention to as you compare different contractors and equipment is warranties. Equipment warranties are one thing that vary greatly. Labor warranties also vary. Most contractors offer a 1 year labor warranty, although I have seen some who lately are only offering a 30 day labor warranty. Also some contractors offer longer labor warranties. I would suggest that if they are offering you a longer labor warranty that you make sure this is through a manufacturer. This way if the contractor would go out of business your warranty would still be good. 

I would be glad to offer my opinions on diffferent types of systems or equipment, even if you are not considering my firm to install your system. Just email me at john@ejtson.com and I will respond promptly with my opinion on your question.