Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Ok so a central AC system is technically not outdoor power equipment, but the condenser is outdoors and it is powered.  So I'm looking for some advice from the board that has given me great advice on other topics, because it's time to replace the Central AC system in my house (20 year old air handler leaking freon and a 14 year old condenser).

I'm pretty much looking at the top of the line systems from Carrier (Infinity 18), Trane (XLi 19), and Lennox.  Does anyone have any experience with these units and recommendations as to one manufacturer versus the other.

Right now I'm favoring the Trane, but I am somewhat concerned that it is a Freon based unit, not Puron. Now I know Freon will remain available essentially for the entire useful life of any new AC system, so if there any reason not to still purchase a Freon based system?

Any suggestions would be much appreciated.

i really think the major brands are about equal, but some food for thought:
Now is the time to install if one is going to do it. its my understanding, government requirements are mandating the increas in the seer rating of new installations and the hvac contractors are telling me ac installations will about double in price.and will require changing out the compressor unit, (on existing installations) as well as the condenser in the air handling unit, as the two styles are not compatable.  manufacture of the higher seer rated units has begun and while sale of the old style isnt prohibited when the're gone, they're gone.  preliminary cost analysis ive seen shows that even with the higher effeciency ratings of the new units, still projected a higher yearly operating cost on the more effecient unit (because of equipment cost difference) than the previous style unit. so while they may be more energy effecient its till going to cost more to install and run.