Guide To HVAC Refrigerant Line Insulation

  • September 15, 2022
  • By MR COOL

Air conditioner refrigerant line insulation is easy to install and can make a difference in your unit’s cooling capability. Like all insulation, the type used for your refrigerant lines protects the system from excessive heat transfer and inefficient operation. 

Whether you’ve just installed a new unit that needs insulating around the refrigerant lines or must replace worn AC line insulation, learn more about the process to reduce the time and effort it takes to complete. 

Why Do Refrigerant Lines and Pipes Need Insulation?

Lines leading from the inside of the house to the outdoor condenser include the liquid line and the suction line. The smaller liquid line releases heat through the pipe’s copper material and feels warm. This line does not require insulation because covering it reduces its efficiency in releasing heat. The suction line will feel cold to the touch because it carries cooled refrigerant that leaves the condenser. This line is the one to insulate. 

Refrigerant lines and pipes should have insulation around them to protect them from damage and inefficiency. Winter erosion, UV damage and condensation may require insulation replacement to avoid temperature fluctuations or malfunctioning. With worn insulation or no insulation at all, refrigerant lines may absorb heat, reducing the system’s cooling capacity.

Closed-cell insulation is one way to combat this because of its sturdy structural makeup, designed to trap more air and keep heat against the insulated object. When choosing close-celled insulating material for your AC pipes, consider the following refrigerant line insulation requirements: 

  • UV protection: Because the AC lines are outside, the insulation covering the suction line needs protection from sun damage. Over time, UV rays will break down the insulating material. Quality insulation should have built-in protection from this type of damage to reduce how often you need to replace the pipe coverings. 
  • Moisture control: Moisture naturally occurs around the suction line from condensation. However, moisture and rain from outside the pipe can erode insulation. Choosing quality insulating materials can prevent premature moisture erosion.
  • Damage prevention: Insulation completely covers the larger suction line. This extra layer provides protection against external damage that could happen to the pipe, such as rocks kicked by a lawn mower or squirrels scratching at the pipe.

How Often Should Refrigerant Line Insulation Be Replaced?

Over the cooler months, your AC system may experience a buildup of dust or dirt on the lines leading to the outdoor condenser. Plan to replace the AC line insulation at the end of the winter each year. Making a priority of installing new insulation before the summer season ensures your system is ready for use. Because refrigerant line insulation cost is so low, replacing this covering is also a cost-effective method of saving energy and making your AC system more efficient during the summer. 

The added benefit of replacing the condenser line insulation is that you won’t need to turn off the AC unit to stop condensation from forming on the line. 

What Type of Insulation Is Used for Refrigerant Lines?

Refrigerant lines use diverse types of insulation. Common materials for AC insulation wrap include foam rubber, polyethylene foam and fiberglass. Among these, the best balance of cost and effectiveness is in polyethylene foam products. These have close-celled designs to prevent moisture intrusion. 

The easiest type of insulation to install is a pre-packaged sleeve design, such as pre-packaged AC insulation wrap sleeves. These may come pre-slit or require some manual preparation. With sleeves, you have the correct type of insulation in a simple-to-install format that reduces your time on the job. 

Like insulation inside your home, the insulation you use for your refrigerant lines should have an R-value that matches the climate of your area. The higher an insulation’s R-value, the more effectively it can insulate. Check your owner’s manual for your AC and local R values to find the appropriate insulation grade to use. You can also find your approximate R-value zone and target through the U.S. Department of Energy’s website.

How to Insulate AC Refrigerant Lines

To insulate your AC refrigerant lines, take the following steps: 

1. Remove the Old Insulation 

When insulating your AC refrigerant lines, you must remove the old insulation with a razor or utility knife, being careful not to nick the copper pipe. It’s always good practice to wear personal protective equipment (PPE) when handling any type of insulation.

2. Measure and Purchase the Insulation and Materials for Your AC Lines 

Measure the diameter of the pipe to ensure you get an appropriately sized insulating sleeve to fit around the pipe snuggly. Measure the length of the pipes to determine how much insulation to purchase and add an extra half-inch or so to the measured lengths to account for any pipe contraction and expansion. Have enough insulation on hand to cover the suction pipe outside to protect against moisture damage from condensation and the line inside to prevent pipe sweating. 

Don’t forget to purchase electrical tape to seal between the insulating sleeves and separate insulating tape to seal any unslit insulation. 

3. Preparing the AC Line for Insulation 

If your air conditioner is on, shut it off to raise the temperature of the suction line until it no longer creates condensation on the outside after you wipe it clean with a towel. Clean off any dirt from the pipes to ensure better longevity for the insulating sleeves. 

4. Cut the Insulating Sleeves to Size 

Measure the length of the line and add your extra half-inch. Cut each sleeve to this measurement. Most sleeves come pre-slit with adhesive strips inside the slits. If you purchased unslit sleeves, make a cut through one side of the insulation to the center of each cut piece. 

5. Install the Insulation Sleeves 

Open each cut sleeve and place it around the suction line. Peel off the backing material over the adhesive on the slit and press the sides together. If using unslit sleeves, apply insulation tape along the slit and press the sides of the slit together to seal. Check that the insulation lays flat against the pipe all the way around. 

6. Seal Sleeve Joints 

Where two sleeves come together, wrap electrical tape around the edges of the two sleeves to join them.

Choose MRCOOL Products and Parts for Your Home’s HVAC System 

At MRCOOL, we create reliable heating and cooling units designed for both DIY and professional installation. We also make the parts needed to maintain and service those units. If you need parts or a new AC unit, visit your local MRCOOL reseller. We also offer technical support via our contact page if you have questions about your MRCOOL air conditioner. See for yourself how MRCOOL HVAC systems provide you with comfort made simple.

8 thoughts on “Guide To HVAC Refrigerant Line Insulation”

  1. I am surpriesed if I cannot set the MRCOOL remote to be in degrees celsius.
    I live in Canada and we use the Metric System here so it would be wonderful if the controller could be set (reset?) to display degrees C rather than only degrees F

    How can I reset my remote???

    1. Try pressing the up and down arrows at the same time for three seconds. If this does not alternate the temperature display between Celsius and Fahrenheit, please give us a call at 270-366-0457.

  2. In my installation, I need to run refrigerant lines down left side of inside unit or else run the lines down inside closet wall to crawlspace out to compressor unit. What do you recommend?
    Also, I want to install my compressor on outside wall 6 feet below inside unit. Recommended 8 feet below, or will 6 feet below work?

    1. The line set will come out of the right hand side of the unit if you’re looking straight at the front of the indoor unit. It would not be able to have the line set come out of the left side, so it seems like running the line set inside the closet wall might be the best solution. 6 feet below should work.

  3. We have foam rubber covering refrigerant lines on a flat roof. After 2-3 years, it has deteriorated due to UV and seagulls. Would your polyethylene or fiberglass product be a good replacement? Are they durable? What are your prices? Can I buy from you…or do I go through a dealer?

    1. We don’t sell direct, so you would need to purchase from one of our retailers. You can find our retailers on our Where to Purchase page. This being said, the insulation would likely be a part that you would need to request, rather than a product that we have for sale. Please give us a call at 270-366-0457 for more information. We do however have our 12 foot LineGuard line set cover available at our retailers, but this provides cover and protection from the elements more than it does insulation.

  4. Re: Storage of excess refrigerant line when wall mounting the external unit.
    I know the line should be coiled flat however since I am planning to mount my unit 4 feel off the ground to accommodate snow accumulation (and providing a roof) does this meant that I would be wise to construct a covered shelf or table to accommodate and protect the excess line? Dropping it to the ground and coiling it there might be possible however I would think that this could expose the line to ice and other damage. Thanks.

    1. While you should try to store the line set horizontally if possible, it should be alright if the line set is looped vertically as well. If you are willing to construct a shelf or stand for the excess line set, that should work well.

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