When changing the outdoor unit, should the indoor unit also be changed?

The answer is, most likely yes. Here's why.

Matched System Design: All air conditioner and heat pump outdoor units are speciallydesigned to work with a matched indoor unit for optimal efficiency and performance. The effect of this matched equipment is a synchronized, top-performance team that ensures dependability and efficiency. Air conditioner and heat pump outdoor units may ”operate” with indoor units other than those for which they have been speciallyconstructed; however, the outcome would be a definite compromise in system performance.

Design Advances: Over time, indoor blower coil units have undergone many design advances — especially in the areas of air handling performance, filtering efficiency and operating sound levels. An up-to-date outdoor unit will also incorporate the latest design advances.

Higher Cooling And Heating Efficiency: The cooling and/or heating efficiency ratings that are advertised for an air conditioner or heat pump are based on their performance as matched systems. While changing only the outdoor unit may consequence in improved efficiency when compared with your old system, it will not be as efficient as it was designed to be, and your savings will be lower than with a matched system.

Equipment Age: If an air conditioner or heat pump is 10 years old or more and needs to be replaced, the indoor unit is likely just as old and has been subjected to the same amount of wear and tear. Changing both units means you won't have to replacethe indoor unit in just a short time… you'll have more years of efficient service from both units.

New Warranty: A new system also delivers you a new product warranty. Changing the indoor unit together with the outdoor unit results in peace of mind, knowing that the new warranty covers the entire system for the same period of time.

A Bargain: At first glance, replacing only the outdoor air conditioner or heat pump may appear to be a savings. But, when you consider the lower cooling and heating efficiencies, decreased reliability and high cost of ownership that results, it's not such a bargain. Replacing an entire system may cost more, but the result is efficiency, reliability and comfort for years into the future.