Ok...there are things that you should be aware of. You have an excellent opportunity to get high efficiency equipment installed and at a good price. The Federal Gov. is still offering up to a $1,500.00 Federal Income Tax Credit through the end of the year. Also most manufacturers are offering pretty good rebates, not to mention your utility companies should be too. There is a lot of money to be saved right now if you buy. I would also recommend only dealing with companies in good standing with the BBB, and getting references from friends is always good. Realize that dealing with someone who does it on the side saves you money now, but they are not authorized to do warranty repairs if need be later. You have to be licensed and bonded in order to deal with Manufacturers and warranty claims. (at least in my state). That brings me to warranties....I highly recommend purchasing the extended warranty, which should add around $300-500 to the purchase price. This will cover all labor charges related to repairs for the next 5-10 years (whichever you buy). The standard labor warranty on new installations is 1 year. After that first year you will be responsible for all labor charges (which is $79.00 hr. here and we're cheap). The extended warranty will pay for itself and you will not have to worry about anything. Im not sure if I have helped or not, but I hope so. I wish you luck whatever you decide to do.