What are the differences between the xr13, xr14, and xl15i?
That pretty much seem the same as far as performance goes. I guess the XL series has a 12 year compressor warranty. Also, as far as extending the warranty to 10 years if a matched system is used, is it critical to install a Trane thermostat to get the extension? I have read that the Honeywell IAQ is better than the Trane branded equivalent.