The Comfort model adds things such as compressor protection switches, a more durable cabinet to protection the coil, better exterior finshes, and compressor covers to make the unit quieter. In general the construction and components are a better quality.

The Base model is designed to be an inexpensive unit for home builers. If you plan to be in the house more than 5 years, then in my opinion the extra money for the Comfort model is a good investment.

There may also be a difference as to how the defrost mode operates, timed verses demand, not to mention SEER & HSPF. Have all the details explained and compared.

SR

This is EXTREMELY confusing. Carrier seems to have changed their lines. According to the Carrier website, the lowest line was formerly the "Base" series. Now the lowest is called the "Comfort/Base" series, including the 25HBC3 and 25HBC5. The AHRI database shows these as "Base" units.

The next line up is now called "Performance/Comfort" series, and includes 25HCB3, 25HCB6, 25HCC5, 25HPA5, 25HPA6. The first of 3 of these show up on AHRI as "Comfort", and the last two as "Performance" (but discontinued.)

I'm assuming that although Carrier now calls the 25HBC units "Comfort," the preferred one is the 25HCB the appearance is from the Product Data sheets seems pretty similar.