rating iconrating iconrating icon

Dirty Evaporator Coil

December 29, 2025
dirty evaporator coil

How It Can Affect Your HVAC System

You probably have some working knowledge about your air conditioner, but do you know how the evaporator coil operates? Evaporator coils are an essential part of your air conditioning system and if you have an older HVAC system, it is possible the coil may have already accumulated dirt overtime. It is important to perform routine AC maintenance to keep not only your evaporator coil running properly but the rest of your HVAC system running efficiently as well. If you were to leave a dirty evaporator coil it could lead to more costly AC repair or even a full AC replacement. Below find out how a dirty evaporator coil could impact your HVAC system.

What Are Evaporator Coils?

An air conditioner’s evaporator coil is the part of the HVAC system where the refrigerant absorbs heat. It is where the cold air comes from. Unlike a furnace that produces heat, an air conditioner does not actually produce any cold air. Instead, the evaporator coil uses refrigerant to absorb heat from the air and carries outdoors. The refrigerant in your system constantly circulates to remove heat until the indoor temperature reaches the set temperature on the thermostat. The evaporator coil is located inside the home or near the air handler in a split-type ac system. The evaporator coils are made from copper, steel, or aluminum because these metals conduct heat easily. In residential settings, they are usually bent into U shapes and protected by fins which help attract heat and moisture.

Symptoms of A Dirty Evaporator Coil

It is important your evaporator remains clean to function efficiently and properly. If your air conditioner is not properly cooling your home, a dirty evaporator coil may be to blame. Even a minimal layer of dust on your evaporator coil can reduce its efficiency, because it will not be able to absorb as much heat as when its clean. Your system will now have to run longer to reach your desired temperature using more energy.

AC Is Not Cooling

Dirt and dust limit the evaporator coil’s ability to absorb heat from the air. Any dirt or dust on the coil acts as a layer of insulation between the air and the refrigerant in the coil. This will make it difficult for it to absorb heat from the indoor air and will result in higher indoor temperatures.

Higher Energy Bills

If your air conditioner has a dirty evaporator coil it will have to work harder and for longer periods to maintain the same desired temperature. If your energy bills have increased, but weather has remained relatively the same, it may be due to a dirty evaporator coil. A dirty coil is significantly less efficient at removing heat from indoors.

High Indoor Humidity

Another function of the evaporator coil is to pull humidity out of the air and recirculate the air that make makes your home feel comfortable. A dirty evaporator coil will not address indoor humidity as efficiently as a clean evaporator coil.

Frozen Evaporator Coil

In more extreme cases a dirty evaporator coil can lead to the development of ice on the coil. Refrigerant circulating throughout a dirty coil will not warm up as much as it should. The very cold refrigerant will cause the water vapor along the coil to freeze. The ice will then continue to accumulate until any remaining heat absorption is completely blocked.  If you allow your system to continue to run with a frozen coil it could raise the compressor temperature eventually leading the component to completely fail. A dirty condenser coil, dirty air filter or a refrigerant leak can all also cause the evaporator coil to freeze. Turn your air conditioner off if you notice any ice on the coil and contact a professional to inspect the issue.

Clogged Condensate Drain Line

When an evaporator coil absorbs heat, it also creates moisture along the coil. The excess water drips from the coil and into pan, where it leaves the system through the condensate drain line. If the water dripping from into the drain line contains dirt or dust it can easily lead to a clogged drain line. Water will then overflow from the drain causing water damage, high humidity, and even health hazards from mold spores.

Give LA Heating & Air A Call Today

You may find DIY methods online, however any evaporator coil cleaning, maintenance, and repair should be left to a professional. While you may think a dirty evaporator coil is a minor issue, it is important to reach out to a professional as soon as possible to prevent costly AC repairs or early complete breakdown of your HVAC system. This is why routine AC maintenance is so critical for your system to operate properly and efficiently. Give LA Heating and Air a call at 818-341-3406 or contact us online for any air conditioner repairs, maintenance or installation service you need.

Dirty Evaporator Coil: How It Can Affect Your HVAC System related posts:

Customer Reviews & Testimonials

Shape- Social Media IconShape BG CTA

New In Our Blog

Piggy Bank with cash falling out near AC

Why Load Calculations Are Essential for Heat Pump Installation in Los Angeles

Discover how Manual J load calculations ensure accurate heat pump sizing, better comfort, lower energy bills, and compliance with Los Angeles rebate and Title 24 requirements.

Piggy Bank with cash falling out near AC

Heat Pump Rebates in Los Angeles (2026): Complete Guide to HEEHRA, LADWP, Burbank, Glendale, Federal Tax Credits & More

See all heat pump rebates available in Los Angeles, including HEEHRA, LADWP, Burbank, Glendale, GoZero, SCE incentives, and the $2,000 federal tax credit

Piggy Bank with cash falling out near AC

Heat Pump Installation & Electrification in Los Angeles: Complete Cost, Rebate & Contractor Guide

Heat pumps are rapidly becoming the preferred HVAC solution for Los Angeles homeowners looking to reduce energy bills, improve comfort, and qualify for major California rebates. This hub is your complete, authoritative guide to everything you need to understand before replacing your AC or furnace with a modern heat pump — including costs, rebates, system sizing, and how to choose the right contractor.

Piggy Bank with cash falling out near AC

Heat Pump Installation in Los Angeles: How to Choose the Right Contractor

This guide explains how heat pump installation works in Los Angeles and what homeowners should look for when choosing a contractor. It covers installation requirements, common mistakes, certification and permit considerations, pricing factors, and how to avoid issues that affect comfort, rebates, and long-term performance—so you can make an informed decision before installing a heat pump.

Piggy Bank with cash falling out near AC

Why TECH-Certified Contractors Are Required for Heat Pump Rebates in California

If you’re considering a heat pump in California, this post explains one critical requirement most HVAC companies leave out: TECH certification. You’ll learn why the state requires TECH-certified contractors for rebates, how certification affects install quality and system performance, and what can go wrong if you choose the wrong installer. It also shows how TECH compliance protects you from denied rebates, poor airflow, and systems that can’t keep up with LA heat—so you can make a confident, informed decision before you install.

Piggy Bank with cash falling out near AC

The HVAC “$5,000 Rule” — A Simple Way to Know When to Repair or Replace Your AC

Learn how the HVAC $5,000 Rule helps you decide whether AC repair or replacement makes financial sense. Simple formula, expert guidance for LA homeowners.

We Install and Service All Major Makes and Models

{ "@context": "https://schema.org", "@type": "Organization", "name": "LA Construction Heating and Air", "url": "https://www.laheatingairconditioning.com" }