What Is an Evaporator Coil and What Does It Do?

Quick Answer

The evaporator coil is the indoor coil where refrigerant absorbs heat from your home's air, cooling and dehumidifying it. It works as the indoor partner to the outdoor condenser, and the two run together as one cooling loop.

What Is an Evaporator Coil?

Quick Answer:

The evaporator coil sits inside, on or near your furnace or air handler. Cold refrigerant runs through it, and as your blower pushes warm household air across the coil, the refrigerant absorbs the heat from that air.

As the coil cools the air, moisture also condenses on it and drains away, which is how your AC dehumidifies. The cooled, drier air then returns to your rooms through the ducts.

What Does the Evaporator Coil Do?

Quick Answer:

It absorbs heat from your indoor air. The refrigerant inside the coil evaporates as it picks up that heat, then carries it outdoors to the condenser to be released. That is the heart of how your home gets cooler.

Because it also pulls moisture from the air, the evaporator coil is central to both comfort and humidity control. A clean, properly working coil is essential to efficient cooling.

Why Does an Evaporator Coil Freeze or Fail?

Quick Answer:

A coil freezes when airflow is too low or refrigerant is too low, both of which let it get cold enough to ice over. Dirty filters, blocked vents, a dirty coil, or a refrigerant leak are the usual culprits.

If you see ice on the coil or refrigerant line, turn the system to fan only and call a technician. Running it frozen can damage the compressor, so the cause needs fixing before you cool again.

At a Glance

Honest Fix believes an informed homeowner makes better decisions, so we explain the why behind your system in plain language. When you need service, you get straight answers and honest fixes, backed by the Lifetime Trust Shield.

Frequently Asked Questions

Where is the evaporator coil located?

It is indoors, usually inside or right above your furnace or air handler. Because it is enclosed in the cabinet, inspecting or cleaning it is typically a job for a technician.

Why does my evaporator coil freeze up?

Freezing usually comes from low airflow or low refrigerant. A dirty filter, blocked vents, a dirty coil, or a refrigerant leak can each let the coil get cold enough to ice over. The cause should be fixed before running again.

How often should an evaporator coil be cleaned?

Most coils benefit from a check during the yearly tune-up, with cleaning as needed based on how dirty they get. A coil in a dusty home loads faster, so a technician cleans it when buildup starts to hurt airflow.

Have a Question About Your System?

Still have a question about your system? Call Honest Fix at (740) 825-9408. We will explain what is going on in plain language and give you an honest recommendation, with no jargon and no pressure.