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AC or heat pump compressor motor insulation kit - noise or sound reduction - cited & discussed at InspectApedia.comHVAC Compressor Sound Insulation
Sound / Noise Reduction for air conditioners, heat pumps, refrigeration equipment

Why do we insulate the compressor/condenser motor on some air conditioners & heat pumps?

Can a fence around the condenser unit reduce noise without causing service or equipment life problems?

An AC or heat pump compressor motor noise blanket or industrial noise curtain reduces the total sound output of the unit by about 5 db, perhaps up to 50% by reducing the passage of noises to the unit exterior.

This article series explains the use of insulation on HVACR systems including motors & refrigerant piping insulation.

Page top photo: the Brinmar Sound Blanket, an AC compressor sound blanket sold by HVAC suppliers & other vendors. This compressor cover was the one we found most-widely sold during our informal compressor noise cover survey made in October 2022. It is sold for about $85. U.S.D.

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HVAC Compressor Motor Insulation

HVAC compressor motor sound blankets cited, explained, discussed at InspectApedia.com - insulation on the compressor motorThe noise from an air conditioner or heat pump condenser unit can be a nuisance or worse depending on the size, condition, and installation details of the unit. Some industrial HVAC compressors can produce noise levels at or exceeding 90dB!

Illustration: examples of air conditioner or heat pump compressor motor insulating covers sold principally for use in noise reduction. The effect of these covers on the compressor motor life is also discussed below on this page.

Watch out: if you are responding to a complaint of excessive noise at a condenser unit, before blaming the compressor or adding a sound insulating blanket or enclosure remember to check these basic sources of condenser unit noise:

[Click to enlarge any image]

When choosing an HVACR compressor motor sound reduction cover, consider a cover that is made specifically to fit your compressor motor brand and model. Compressor noise-control insulating covers are made by several manufacturers and sold sized to fit specific compressor brands including Alliance, Copeland, Bryant, Carrier, Goodman, Rheem, McQuay, Tecumseh, Trane, and York compressor motors.

Watch out: If you are thinking of a do-it-yourself compressor noise blanket, when choosing a compressor motor insulation material keep in mind that simply wrapping the motor in fiberglass is a mistake - the insulation will become wet, hold water against the motor, become ineffective, and may risk electrical shock or failure, or may come loose and get sucked into the fan system.

Also take care when building sound-insulating walls or boards around the condenser unit: don't violate the manufacturer's clearance distances nor air-flow requirements lest you increase the unit's operating cost and cause it to overheat, shortening its life.

The following Q&A discuss a reader's discovery of an insulating blanket on the compressor motor of an air conditioner condenser unit installed in Florida.

On 2022-10-15 by InspectApedia (Editor) (mod) - Sound blankets for A/C or heat pump compressor motors

Insulation on suction line & on compressor motor (C) InspetApedia.com Gergen

@Anonymous

Why Insulate the AC or Heat Pump Compressor Motor Itself?

Yours is a different situation entirely.

The insulating jacket on the compressor motor itself is usually installed primarily to reduce the noise level of the condenser unit.

Particularly when the condenser unit is close to occupied spaces such as an outdoor patio or deck, an HVAC technician may install a sound cover on the compressor to reduce noise complaints by building occupants - a common installation detail in states like Florida.

Separately at REFRIGERANT PIPING INSULATION we explain the importance of insulation on refrigerant piping - also show in your photo and the original subject of your question [below].

In a HOT climate the role of insulation on the suction line is to keep it cool - to avoid excessive warming that in turn would make the compressor/condenser unit have to work still harder to compress returning refrigerant gas when compressing it, then cooling it back to liquid refrigerant.


Below we show a typical insulating jacket sold for AC & Heat Pump Compressor Motors, produced by Armstrong and selling for around $100. U.S.D. - Armstrong R100673-01 Compressor Insulation Wrap

In the trade these are called an HVAC Compressor "Sound Cover" or "Compressor Sound Blanket".

On 2022-10-15 by Anonymous - insulation on the compressor motor in Florida

anonymous follow-up:

Hi. The opposite. I am in scorching Florida climate. Advise.

On 2022-10-15 by InspectApedia (Editor) (mod)

@Anon,

Looks like a careful installation - I suspect you are located in a sometimes freezing climate and that this is a heat pump. Am I right?

The installer has also added an insulating jacket on the compressor motor itself - not something I've seen in cold climates..

Do give us your location.

On 2022-10-15 by Anonymous

from Anonymous

Here's a photo of the inside of my condenser unit -

>Insulation on suction line & on compressor motor (C) InspetApedia.com Gergen

On 2022-10-15 by InspectApedia (Editor) (mod) - good practice, rather than harmful, to insulate refrigeration lines right up to the compressor motor

@Anonymous by private email,

No, not at all, it's harmless to have insulated refrigerant piping close to the compressor motor (inside the condenser) and in some climates it may even be necessary;

And it is perhaps a more-meticulous job than usual.

I'd like to see a photo of your condenser and refrigerant piping installation. That may let us comment further.

On 2022-10-15 by Anonymous by private email

Is the pipe in this picture (from your website), that is always suppose to be insulated on the outside, not insulated within the condenser unit for some reason?

My question is, is it better to cover the pipe or should it be always exposed, (because there is actually a valid reason for it being exposed) even though it is subjected to the elements?

Please, advise.

How to install an HVAC Compressor Noise Control Blanket

Watch out: don't work on an AC or heat pump compressor unit with the cover opened or removed before turning off power. Otherwise if the motor starts you could be badly injured by the spinning cooling fan.

Typically the procedure is quite simple:

  1. Remove the compressor noise blanket from its packaging where it was probably shipped in compressed form, and shake it a bit to allow it to fluff up.
  2. Open the blanket and, depending on its design you'll either slip over the the compressor or wrap it around the compressor.
  3. In either case align the noise cover slots or openings positioned to clear the refrigerant suction and high pressure line.
  4. Some compressor noise blankets include a separate top cover that is then installed, and
  5. Most of these compressor noise blankets are secured with velcro or similar strapping.
  6. If all else fails do the unusual thing: read the installation instructions provided by the compressor noise blanket manufacturer.

Does HVAC Compressor Motor Damage the Motor or Shorten Its Life

Goodman 4 Ton Heat Pump 19 SEER Inverter Split System cited & discussed at InspectApedia.comMost sources we reviewed agreed that covering the compressor motor itself won't damage the motor nor decrease its life nor increase its operating temperature.

The compressor motor is cooled principally by the returning refrigerant gas in the suction line.

Really? Yes, in fact some high-SEER HVAC compressor motors like the Goodman 4-Ton 19 SEER Inverter Split System shown here are delivered from the factory wrapped in sound-deadening insulation.

Product specification excerpt:

High-density foam compressor blanket provides noise reduction when the compressor is in operation.

Keep in mind that while the hot, compressed, refrigerant gas indeed must be cooled to a liquid by blowing air across the condensing coil in the condenser unit, the compressor motor itself is not providing that cooling, and the compressor motor temperature itself is cooled down chiefly by returning refrigerant entering on the suction line or low-side of the motor.

If your compressor motor is overheating most-likely there is another cause such as improper refrigerant charge or a failing motor or motor bearing.

Is a Sound-Reduction Fence Around an Air Conditioner or Heat Pump Compressor OK & Effective

OPINION: to significantly-reduce noise from a compressor/condenser unit a surrounding fence would need to be nearly-solid, preferably built of sound-absorbing materials such as fiberboard, and would need to be both horizontally sufficiently-far from the condenser unit so as not to block its required air-flow, and enough higher than the unit that noise doesn't simply pass right over the enclosure.

Typically you need two feet or more of horizontal clearance distance for air control and three feet or more on two or more sides for working space - or the fence needs to be easily removed for service.

See details

at CLEARANCE DISTANCE, HVAC

Other Condenser Unit Noise Reduction Features

Where Buy HVAC Compressor Noise & Sound Insulating Covers & Related Products

FabSrv AC compressor motor noise or sound control cover cited & discussed at InspectApedia.com

Specialty HVACR suppliers like those listed below provide compressor insulating blankets or sound control packages


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Continue reading at REFRIGERANT PIPING INSULATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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Suggested citation for this web page

COMPRESSOR MOTOR INSULATION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

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