What Is An Ac Coil

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What Does The Evaporator Coil Do

Why Does The Evaporator Coil Freeze (And How to Diagnose It)

September 10, 2019 | Blog

Your air conditioner is vital for keeping your Pelahatchie, Mississippi, home cool. One of the main parts of the system is the evaporator coil. Without it, your AC system wont work correctly. Lets look at the basics of how the air conditioner works and the role the evaporator coil plays.

Air Conditioner Coil Cleaning Methods

How to Clean AC Coils with Compressed Air

Your dealer may use a combination of using compressed air, a shop-vac and heavy-duty coil-cleaning chemicals that meet the specifications of your air conditioner model. This method is typically recommended only for the outdoor condensing coil. Cleaning the indoor evaporator coil with compressed air will blow dust and debris inside the home. Using compressed air can be a quick and reasonably effective method to remove surface dust, dirt and debris from the coil. When cleaning an outdoor coil with compressed air, an HVAC dealer will blow the air through the coils opposite the direction that air flows through the coil during normal use. This will result in pushing air through the cleaner side back through the dirtier side. Your dealer will be careful to blow the air straight through the fins, not at an angle. This is because the fins are very thin metal and bend easily. Using the shop vac, the service technician can then clean the unwanted dirt and debris from the unit. These actions will remove mostly loose, surface materials from the coil. To remove more stubborn buildup, your dealer can follow up with either a household detergent or a commercially available coil cleaning solution.

How to Clean AC Coils with Household Detergent

How to Clean AC Coils with Commercial Cleaners

How To Know That Your Evaporator Is Leaking

A leaking evaporator is caused by internal corrosion. To confirm that your ACs problem is leaky AC coils, here are some of the most common symptoms you would encounter:

  • Longer cooling time
  • Weaker airflow
  • Repeated need for refrigerant fill-ups

When you experience these signs, it would be best to call HVAC technicians so they can confirm if your hunch is true. Usually, air conditioner problems share the same symptoms, so it would be wise to seek the help of a licensed professional. They would conduct tests and inspections to know the real cause of your AC problem. More importantly, they would recommend the best solutions to your problem.

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Airflow And Cooling Capacities

Just like AC systems, evaporator coils have maximum cooling capacities. So, the replacement model needs to have the same output as the units original part. Most manufacturers produce the same evaporator coil in multiple sizes so that you can get the version that fits your AC system.

Most models are available in sizes that range from 1.5 to 5 tons, but finding 12,000 BTU or 9,000 BTU models shouldnt be too difficult.

Should I Replace My Acs Evaporator Coil Or The Whole Ac Unit

What is an Evaporator Coil â Differences Between âAâ? and âZâ? Types

If youve been told that your ACs evaporator coil is damaged, youre probably thinkingbig deal, I can just replace it, right?

Well, its not always that easy.

In some situations, replacing just the evaporator coil means it will mismatch your condenser . And if the condenser and evaporator mismatch in either age, SEER or refrigerant, youre going to run into problems like:

  • High energy bills
  • Less comfort
  • A unit that will die much earlier than it should

Well explain what we mean by mismatching coils and when you should replace the entire unit versus just the evaporator coil. But first, lets take a quick look at what an evaporator coil does and how it can get damaged.

Need professional advice on replacing your ACs evaporator coil vs replacing the entire unit?

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Evaporator Coil & Condenser Coil For Dallas Homeowners

An air conditioning system has two coils, condenser coils and evaporator coils usually made of copper tubes with aluminum fins. The evaporator coil, or indoor coil, is often described as the cold coil because it provides indoor cooling. The coil works by absorbing heat from the indoor air that is blown over by the air handlers fan. The condenser coil or outdoor coil is the warm coil as it rejects the heat as a fan blows outside air over the surface.

This video shows the difference of condenser coil and evaporator coil.

Inside And Outside Temperatures

Your heat pump and air handler will not function very well when outside temperatures are below 60 degrees. Sometimes, the evaporator coil will freeze if the A/C is running when its cool outside.


Diagnose your thermostat for any obvious problems. Try to avoid using your air conditioner at night when the temperatures drop. We recommend setting your programmable thermostat to 78 degrees or higher while at home and 84 degrees or higher while away from home. Setting your thermostat too low, especially when it isnt that hot out, can cause your system to malfunction and freeze up.

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When To Replace Your Ac Evaporator Coil

Here are a few signs that denote you need to replace your AC evaporator coil:

Poor Cooling

An evaporator coils fundamental task is to cool the air. So if you experience your AC unit isnt cooling properly, the problem may lie with your evaporator coil.

Over time, the AC coil can rust or get damaged in other ways. As a result, it cant properly conduct heat absorption, forcing it to blow warm air rather than cool air.

Related Article What To Check If Ac Is Not Cooling The House?

Frost Build Up

This a rather annoying issue as it makes your air conditioning system turn off/on frequently, using much more electricity than usual.

Hence, the AC compressor cycles more frequently because the evaporator coil fails to cool down the indoor air due to ice build-up on the surface.

Related Article A Quick Fix For A Frozen Evaporator Coil


You may often see water trickling from the coil. In small quantities, its fine as its just the water condensed from your indoors.

But, if you experience excessive water dripping from the coil, chances are the coil may have a leakage. Mainly, this problem occurs when the evaporator coil itself gets damaged.

Related Article Troubleshoot A Leaking Evaporator Coil

Unusual Noises & Sounds

Often, the AC unit will make unusual noises when its evaporator coil has a problem. Hissing, banging, or clanging may signal that the AC coil has to be replaced or repaired.

Related Article What Noises Point To Ac Having Problems?

Dirt, Deposits & Corrosion

How Does My Air Conditioner Work

How To Clean Your AC Condenser Coil

The air conditioning system actually revolves around heat transfer. The AC system has an indoor unit, the evaporator coil, and an outdoor unit which houses the compressor, condenser coil, and a fan. The units connect through lines that contain a chemical fluid known as a refrigerant. The inside evaporator allows the refrigerant to absorb heat that is in your home.

The fluid containing the heat then flows to the outside unit and is released outside. The compressor keeps the fluid moving throughout the system, constantly reusing the same refrigerant. As the fluid is moving back into the house, it moves through the condenser, which blows air over it and cools it. That cool air gets blown into your house and the refrigerant once again absorbs heat and the loop continues.

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What Is A Central Air Conditioner Evaporator Coil

The evaporator coil is the part of your AC system that actually cools the air before it is blown into your home.

Most homeowners never actually see the evaporator coil because it is covered by a metal case that is usually in an indoor closet or attic. Your evaporator coil is an A-shaped web of copper coils that sits inside your indoor AC unit.

Evaporator coil.

To help you really understand an evaporator coils role within the AC system, lets take a quick look at how your air conditioner works to cool your home.

Coil And Installation Costs

Arguably, the most difficult decision youll have to make is whether you want to replace just the evaporator coil or the entire system. The part itself can cost you between $300 and $1,800 depending on its tonnage, type, and brand.

The installation costs vary from $400 to $1,000, so you may have to spend well over a thousand dollars to repair your AC system. You should opt for a replacement coil that comes with a long warranty period to avoid covering reparation costs in case it breaks down.

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A Closer Look At The Condenser Coil

An AC condenser unit

Once the refrigerant reaches your outdoor condenser unit , its already in a hot gas form. In order for the refrigerant to cool down to a liquid state and repeat the cooling process, the heat needs to escape into the air outside. And this is exactly what your condenser coils are responsible for.

Condenser coil

Your condenser coils sit directly behind the condenser finsthe thin metal wiring that covers your outdoor AC unit . As refrigerant travels to your outdoor unit, it fills the many condenser coils, increasing its surface area so that heat escapes faster.

Condenser unit fan

The condenser unit fan blows air across the condensing coil, which helps push the heat into the outdoor air. Once the majority of the heat is squeezed out of the refrigerant, it cools, returns to a liquid form and travels back to your indoor unit. Then the cooling process repeats all over again.

So your condenser coils are essential to helping your home stay cool. But, if theyre dirty, youll run into problems…

How To Clean A Dirty Condenser Coil

4 Steps to Completely Clean Your HVAC Evaporator Coils

If your outside condenser unit is dirty, try this DIY cleaning method:

  • Remove debris like leaves and sticks from the condenser unit
  • Use a hose on a gentle setting to clear off dirt/debris
  • Cut back any surrounding shrubbery at least 3 feet from your outdoor unit
  • When to hire a professional:

    If you can see that your condenser coil is covered in a thick layer of dust, then its time to .

    A professional has the right cleaning equipment to remove dust buildup from your condenser coils without damaging them in the process.

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    How The Hvac Evaporator Coil Works With The Rest Of Your Ac

    The condenser coil and compressor are as crucial to your AC system cooling down warm air as the HVAC evaporator coil. If either of them breaks or wears down, it has similar consequences to when the evaporator coil fails.

    Once the evaporator coils refrigerant cools and absorbs the heat, the compressor turns it into a gas and directs it to the condenser coil, which sends the heat back outside, leaving your home with nothing but cold air. The condenser coil then sends the refrigerant back to the evaporator coil, where the process continues until you turn the system off.

    Since all three parts are valuable in the heat transfer process, wear and tear to any of them drastically drops your air conditioners efficiency. Unfortunately, HVAC evaporator coils are fragile devices that slow down with something as common as dust buildup.

    The Importance Of The Compressor And Condenser Coil

    As mentioned, the compressor changes the cold refrigerant into gas and sends it into the condenser coil. The coil dispels the hot air to the outside. The refrigerant then loops back to the inside unit in the house, gets cold again, absorbs heat and disperses it to the outside.

    As long as the air conditioner is running, the refrigerant keeps up this continuous loop. Maintaining the proper level of refrigerant is vital or it wont be able to absorb heat. Its important to leave this service to trained service technicians as the evaporator coil needs special handling.

    If youd like to learn more about the workings of your air conditioner or need to schedule maintenance, give Modern Air a call today at 202-5968. Our professionals are ready to serve you.

    Image provided by Shutterstock

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    Proper Maintenance For Air Conditioner Coils

    Removing debris from the outdoor unit is one thing you can do to keep the system working efficiently. You can hose down the outdoor unit to help remove dirt and grime. For a deeper clean however, you should bring in a professional to avoid damaging the coils. Galmiche & Sons specializes in this kind of air conditioner servicing. So give us a call at 314-993-111 to have our experts inspect and clean your air conditioner coils to keep you happy and cool.

    Rheem Rcf6024htamca The Best Coil Replacement For Rheem Ac Units

    Evaporator Coil! How it Works- Refrigerant Flow, Phase Change, Saturation Point, Superheat, Tips!

    A cased evaporator coil like the Rheem RCF6024HTAMCA might be a good solution if you have a furnace, heat pump, or AC manufactured by this brand. This model can be paired with outdoor units the cooling outputs between 18,000 BTU and 60,000 BTU.

    In addition, the N coil design enables you to use this coil with vertical and horizontal AC systems. ITs maximum airflow capacity is 1,900 CFM, while the bi-directional airflow function lets you switch between horizontal and vertical airflow directions.

    • Excellent protection against refrigerant leaks
    • Ten-year warranty
    • Pricing information is available upon request

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    How Does An Air Conditioner Condenser Coil Work

    For you to understand how an aircon condenser coil works, it is important to point out its main function first: a place where all the warm air gets removed. The aircon condenser coil is responsible for the heat transfer process. This is where much of the absorbed heat is transferred from your house and into the open outdoors.

    An AC condenser coil is made up of different tubes that are filled with refrigerant liquid. In order for it to fully function, a chiller inside the coil cools the fluid and moves through the condenser tubing. Once this process is done, itâs further converted into gas. Afterwards, the converted gas is distributed through the entire cooling system.

    After this conversion process is done, the refrigerant then releases the heat and returns to a liquid state. From here, the cycle will continue in a closed system.

    Looking into a condenser coil closely throughout this process will also show you the process of the refrigerant vapor. This vapor is usually processed through a cycle of warm trading loop, allowing it to be turned into a fluid and making the heat from the cold indoor zone get dismissed in the process.

    From this condenser coil process, the aircon is able to provide the quality breeze that every homeowners and office workers expect.

    Web Best Condenser Coil Cleaner

    Web makes a condenser coil cleaner that is safer for the environment and your pets. The biodegradable formula is designed to be sprayed on and rinsed away.

    You wont have to scrub the coils unless there is a major gunk build-up, and you can rinse away from the outside of the condenser without having to access the interior of your condenser.

    When rinsing, you should use nominal pressure from a garden hose and not a spray nozzle otherwise, this will push the solution and debris back into the coils. It is also ill-advised to use indoors on your evaporator coils as there isnt a degreasing solution involved. Surface contamination of the evaporator coils would be cleaned, but the grime and grease will remain.

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    The Benefits Of Keeping Your Coils Clean

    Its important to keep the AC coils clean so that heat can exchange efficiently through the coils without being blocked by dirt and debris. A lack of routine maintenance on the coils can lead to higher energy bills and consumption or an overheating AC system.The condenser coils, being on the outside of your unit, get hit the hardest by dirt and grime. If the condenser coils are dirty, heat wont transfer out of your home as easily. And the harder your unit has to work to maintain your desired temperature, the more costly your monthly bills and the higher the likelihood of your system breaking down prematurely.Although the evaporator coils are located inside your unit, they are still exposed to dust being filtered out of your home. If the evaporator coils are dirty, they cant remove as much heat or humidity from your space and will take longer to cool the air.

    Your Evaporator Coil Removes Heat From The Air

    ASPEN 175R

    What most people dont realize is that ACs dont actually create cool air. They simply remove heat from the indoor air, which is where your evaporator coil comes in.

    The evaporator coils are filled with very cold refrigerant . And as warm air from inside your home passes over those cold coils, the refrigerant absorbs all of the heat and moisture from that air. The result? Cold, dehumidified air that gets blown directly into your home.

    Warm return air from the home passes over the evaporator and becomes cool supply air.

    But what happens to all of the heat that your evaporator coil has just absorbed?

    Well, that is what that big metal box in your backyard is for. The refrigerant inside of your evaporator coils carries that heat all the way to your outdoor AC unit. From there, your condenser coils dump all of the heat into the outdoor air.

    Your AC repeats that absorb heat/dump heat process until your home reaches your set temperature.

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    Evaporator Coils: How They Work What They Cost And How To Keep Them Clean

    Chances are, youre not interested in a dysfunctional air conditioner that never turns on. And youre probably really not interested in an air conditioner that blows out warm air in the middle of a hot summer day. Thats why its important you keep your air conditioners evaporator coil in the best possible shape.

    Your evaporator coil is a major part of your AC unit because it absorbs heat from inside your home. It then works with other parts of your air conditioner to cool your home by transferring all that heat outside.

    That means if your evaporator coil is broken, your home wont get as cool as you want it. Understanding how an evaporator coil works and what you can do to maintain it will play a big role in saving you the heartache of a broken air conditioner in the summer.

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