What Do You Need to Know About Your Heat Pump Compressor?

Frequently Asked Questions:

"I need a new compressor!"

"Should I buy a new, off-brand, or refurbished heat pump compressor?"

"What is a compressor?"

What does a bad compressor sound like?"

"Do I replace my compressor or my entire heat pump?"

"Do I need to hire a contractor or do I replace it myself?"


"I Need a New Compressor!"

If your current heat pump needs a new compressor, record the make and model of your heat pump and contact a dealer.  Below are links to the most common dealers in your area:

Trane heat pump dealer

York heat pump dealer

Carrier heat pump dealer (enter zip code in upper right hand corner of the page)

American Standard heat pump dealer

Goodman heat pump dealer

Lennox heat pump dealer

Rheem heat pump dealer

Bryant heat pump dealer

Heil heat pump dealer


"Should I Buy a New, Off-Brand, or Refurbished Heat Pump Compressor?"

Pros of a new, equivalent compressor:

  • No risk associated with using a different compressor
  • The warranty of the entire heat pump may stay in place (as long as the other conditions are adhered to)

Cons of a new, equivalent compressor:

  • Typically is more expensive

Pros of an off-brand/refurbished compressor:

  • Typically is less expensive

Cons of an off-brand/refurbished compressor:

  • May be louder
  • May results in a less efficient heat pump
  • The heat pump may need additional "tweaking" for smooth operation

In conclusion, it is worth checking out the price of both an equivalent model and an off-brand model.  

However, buyer beware!

If the price difference is minor.....go with the equivalent model.  While most off-brand compressors do just fine, some do not.  

As a result some homeowners have had to spend more money in the end because the heat pump compressor failed more quickly.


"What is a Compressor?"

A compressor performs two functions within the refrigeration cycle:

  1. Maintains a specific rate of refrigerant flow
  2. Increases the pressure of the refrigerant by "compressing" the refrigerant gas

When problems with the compressor exist, one or both of the above functions are affected.

Is there a difference between a compressor in a heat pump versus a standard air conditioner?

No.

In fact, a compressor used in an air conditioner can be equally exchanged with the compressor in a heat pump (as long as the heat pump compressor performance for the cooling side of each is the same, as well as other criteria such as pressure differential and refrigerant type).

Most modern heat pumps utilize a scroll compressor, as this is typically the  quietest, most efficient compressor for residential and small commercial applications.

Below is a fantastic video from Copeland, one of the largest scroll compressor manufacturers in the world.

It doesn't have any sound explaining the process, but it is somewhat intuitive.  Just note for the video: the blue gas is the low temperature/low pressure refrigerant entering the compressor and the red gas is the high pressure/high temperature refrigerant leaving the compressor. 


"What Does a Bad Compressor Sound Like?"

There are many, many different noise that come from a heat pump compressor which can help to diagnose problems.

First let's hear how a good compressor sounds.  You will hear slight fluctuations in noise as the compressor loads and unloads.

Good scroll compressor:

Next this is a good example of a compressor that is going bad, but still operating.

Scroll compressor going bad:

When a compressor shuts down, internal equalization can cause the compressor to "backspin" if the check valves are non-existent or not working correctly.  Below is an example of what this sounds like.

Scroll compressor backspin at shutdown:


"Do I Replace My Compressor or My Entire Heat Pump?"

To replace, or to not replace. That is the question.

The answer to this question is actually somewhat simple.  Assuming that the technician has made an accurate diagnosis.....

We must determine whether or not the unit is too old to justify a brand new heat pump compressor.

  1. First, compare the cost of each replacement.  Often the labor cost for replacing a compressor is more than the labor cost of installing a new heat pump.
  2. Next ask the dealer to compare the energy efficiency of the new heat pump with that of your existing heat pump.  See our heat pump efficiency tables to determine the energy savings that you can expect to see.
  3. How old is your current heat pump? As a general rule of thumb if the heat pump is less than 5 years old, it is usually best to replace the compressor.  

    A heat pump that is 5-10 years old requires a little more insight.  Due to recent pressure in the HVAC industry for more energy efficiency, a heat pump that is greater than 5 years old is often very inefficient by today's standards.  So if you consider the cost required to replace a heat pump compressor, as well as the energy savings that you would lose by not purchasing an efficient heat pump, usually a new heat pump is the best decision.

    If the heat pump is greater than 10 years old, buy a new heat pump.  Even if you hit the lottery and the heat pump lasts 20 years or more, the energy savings you would lose out on over that time would be significant.

"Do I Need to Hire a Contractor or Do I Replace It Myself?"

Due to high labor costs many people ask this question.  Here are a few things to consider:

  • EPA regulations state that it is illegal to service or repair refrigeration machinery without the certification required to handle refrigerants.  
  • If the refrigerant in the heat pump is bad, the new compressor will quickly go bad as well.  Trained professionals always test the refrigerant for acid to ensure this will not happen.
  • Most older heat pumps contain R-22 which is an ozone depleting refrigerant.  Most newer heat pumps contain a more environmentally friendly R-410a.  You must ensure that you purchase and install all components that are designed to work with the correct refrigerant.
  • The copper refrigerant lines must be isolated or evacuated in order to safely service the compressor.
  • Often a new liquid line filter drier is installed when the compressor is replaced.  This ensures clean refrigerant piping and efficient operation.
  • A compressor that is improperly installed can result in hundreds and sometimes thousands of dollars in extra repair costs.

With all of this considered, many decide to replace the compressor themselves.  Exercise caution and be sure that you are properly trained.  Perhaps there is someone that you know who is certified to handle refrigerant.  In this case, you could perform the work unrelated to the handling of refrigerant.

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