HVAC Units: Should You Replace Indoor and Outdoor Components at the Same Time?

When replacing air conditioning units, remember that the indoor and outdoor components of a central air conditioner are designed to work together.

The indoor unit is composed of the evaporator coil installed inside the air handler that extracts heat from air inside your home. The outdoor unit, typically mounted behind or to the side of your house, includes the condenser coil that disperses the heat into outside air. The two units are connected by insulated lines that circulate Freon refrigerant.

It’s possible that only one unit, and not the other, may be affected by coil corrosion, damage or some other event. Still, when replacing air conditioning units it’s important to replace both, instead of just one. Here are some reasons why:

A/C coils are engineered as a matched set.

The evaporator and condenser coil are calibrated in size and refrigerant capacity to extract and disperse an exactly equivalent amount of heat energy. Installing a new unit while leaving the old one in place disrupts that critical balance and inhibits proper cooling performance.

Efficiency depends on matching coils.

Every new air conditioner comes with an official energy efficiency rating known as SEER (Seasonal Energy Efficiency Ratio). This figure represents estimated energy consumption and monthly costs of operation, allowing the consumer to make an informed buying decision. The SEER calculation for an A/C unit is strictly based on tests utilizing matched, original equipment coils. If you replace only one coil and not the other, you can no longer expect to get the same energy efficiency and costs that were indicated by the original SEER rating.

The warranty requires it.

Most manufacturer’s warranties stipulate that installation of mismatched units including coils voids the terms of the warranty. If you require service or replacement of expensive components like the compressor, you may not get warranty coverage if only one new coil has been installed instead of a manufacturer-approved matched set.

For professional advice and service regarding replacing air conditioning units, contact Energy 1 Heating & Air Conditioning.

Our goal is to help educate our customers in Lorain, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, download our free Home Comfort Guide or call us at 440-201-2959.