Photograph of air conditioning compressor condenser units with many problems Clearance Distances for Air Conditioner / Heat Pump Compressor / Condenser Units

  • CLEARANCE DISTANCE, HVAC - CONTENTS: AIr conditioner or heat pump outdoor compressor/condenser unit clearance distances. Minimum Clearance Distances for a building air conditioner or heat pump unit, Maximum Distances From a Building for air conditioners & heat pumps.
  • POST a QUESTION or READ FAQs about the recommended minimum & maximum clearances or site distances for air conditioner or heat pump outdoor compressor/condenser units
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Clearance distances for outdoor HVAC compressor/condenser units:

This article describes the recommended minimum (and maximum) distances to separate an air conditioner or heat pump outdoor compressor/condenser unit from building walls, other equipment, fences, shrubs, etc. In our photo at page top these two compressor/condenser units are too close together as well as too close to the building walls.

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Air Conditioning & Heat Pump Equipment Minimum Clearance Distances from Building Walls, Shrubs, Other Equipment

Photograph of an overgrown air conditioning condenser

Blocking air flow through the outdoor A/C or heat pump compressor/condenser unit is a really bad idea that shortens equipment life (as the equipment runs hotter) and increases system operating costs (for the same reason - hotter operating temperature means lower efficiency during the cooling season).

Article Contents:

Air conditioning or heat pump compressor/condenser units mounted too close to a wall, surrounded by shrubs, or multiple units located too closely together will probably not receive enough cool air flow to function properly.

And even worse, compressor/condenser units that are too close together not only have to fight for their incoming cooling air, but they may feed hot exhaust air to one another, increasing their operating temperatures still further.

The final authority on proper HVAC equipment clearance distances is the manufacturer's installation instruction manual. But here are some general rules of thumb for air conditioner or heat pump clearances that we will cite here.

[Click to enlarge any image]

In our photo at left the A./C compressor units are too close together and also suffer from airflow blocked by shrubbery. This collection of air conditioning compressors are too many too close together - they will be fighting for cooling air around the condenser unit, increasing operating cost and shortening air conditioner compressor life

Rule of Thumb Lateral or Horizontal A/C / Heat Pump clearance distances

AC compressor too close to house wasll (C) Daniel Friedman

A rule of thumb is to maintain at least two-feet (24") between the A./C compressor/condenser unit and any nearby obstruction such as a building wall, shrub, or fence.

If there are multiple air conditioner or heat pumps installed in the same area, and following the sense of the rule above, I'd keep the units at least 4 ft. apart from one another as well.

In our photo (left) from a home in New York, the compressor/condenser unit actually leaning against the house wall (its support pad tipped). About 1/3 of the air flow from this unit is completely blocked by the building wall.

At least the wall kept the unit from tipping over, though.

Closest recommended clearance distances for A/C or Heat Pump Compressors

If you do not have manufacturer's installation instructions at hand we recommend following the "rules of thumb" for A/C or heat pump clearance distances given above.

But of course the final authority is the equipment manufacturer. Here is an adapted (reformatted) quote of clearance requirements from a Carrier 24ANA Infinity Series Air Conditioner of 2-5 nominal ton size A/C equipment installation manual:

  • General working space around the compressor/condenser
    When installing, allow sufficient space for airflow clearance, wiring, refrigerant piping, and service.
  • Clearance to the service side or end of the compressor / condenser unit
    Allow 24 in. (610mm) clearance to service end of unit
  • Clearance space above an air conditioner compressor/condenser unit
    Allow at least 48 in. (1219.2mm) above the compressor/condenser unit.
  • Clearance space at sides of an air conditioner or heat pump compressor/condenser unit for air flow
    For proper airflow, a 6-in. (152.4 mm) clearance on 1 side of unit and 12 in. (304.8 mm) on all remaining sides must be maintained.
  • Clearance distance between adjacent air conditioner or heat pump compressor/condenser units
    Maintain a distance of 24 in. (609.6 mm) between units.
  • Clearance distances for the compressor/condenser from water, ice, snow
    Position so water, snow, or ice from roof or eaves cannot fall directly on unit.
  • Rooftop clearance distances for A/C or heat pump compressor/condenser units
    On rooftop applications, locate unit at least 6 in. (152.4 mm) above roof surface.

Other Clearance Distances & Protection Advice for the Outdoor Coil / Compressor/Condenser Unit of an Air Conditioner or Heat Pump

Lennox® typical compressor condenser installation instructions (see REFERENCES) include these additional bits of advice about the outdoor condensing coil and compressor unit:

  • Please contact your dealer to schedule proper inspection and maintenance for your equipment.
    Cleaning of the outdoor unit’s coil should be performed by a trained service technician. Contact your dealer and set up a schedule (preferably twice a year, but at least once a year) to inspect and service your outdoor unit.
  • Make sure no obstructions restrict airflow to the outdoor unit.
  • Grass clippings, leaves, or shrubs crowding the unit can cause the unit to work harder and use more energy.
  • Keep shrubbery trimmed away from the unit and periodically check for debris which collects around the unit

    Lennox Corporation, "Installation Instructions, Elite® Series XC13 Units, Condensing Units 506635-01" (09/2011), retrieved 12/2/2014, original source: /Lennox_XC13_IOM.pdf

Reader Question: A/C compressor clearance from entrances

(Feb 19, 2015) Chuck said:
Are there any clearance requirements for condensing units and entrances?



You mean beyond what's in the article above and specific to building entries?

I haven't seen that explicit spec. beyond what's mentioned in the article above or a generic 3-foot rule to give good air circulation. Perhaps in the unit's installation guide you'll see some schematic on clearances that's different. Is this a noise complaint or an air flow concern?

In my opinion and probably the opinion of your local fire or building code compliance officials, the compressor/condenser should not be located where it forms an obstruction or hazard around building entrances. Since an exit stair or door wants at least a 3-foot landing or clearance in the direction of travel it seems to me that'd be a bare minimum and 48" or more makes more sense; imagine trying to bring a couch into a building having to lift it over the AC unit.

Reader Question: A/C compressor clearance to privacy walls

(Aug 4, 2015) Robert Mendez said:
Clearance space above an air conditioner compressor/condenser unit
Allow at least 48 in. (1219.2mm) above the compressor/condenser unit.

My question: what about the distance from the wall stretching out above the unit and to the sides? Any recommendation on the length? My e-mail is


If you're talking about privacy walls or screens at patios or decks, say at a condo, the A/C compressor condenser side-clearance distances specified by the manufacturer (and cited above) need to be respected.

Other building mechanical systems that could interfere with the heat pump or air conditioner compressor-condenser unit

Photograph of air conditioning compressor condenser units with many problems

In our photo at left, from a Minneapolis MN home, these two compressor/condenser units are just about three feet apart - a little close, and that right-most larger compressor/condenser unit is too close to building walls, a clothes dryer vent, and shrubbery.

We also see that direct-vented heating appliance white PVC piping is blowing exhaust close to these units. The installation is nice-looking and neat though.

  • Clothes dryer vent outlet: Do not locate a compressor/condenser unit where the clothes dryer vent will blow onto or close to the unit. Lint-clogging of the compressor/condenser's condensing coils is likely to be a problem and the extra warm air won't help the cooling cycle efficiency or equipment life. Move the equipment or move the dryer vent.
  • Heating appliance direct vent outlet: Do not locate the outdoor HVAC compressor/condenser unit where exhaust from a direct-vented heating appliance will blow onto the unit.
Air conditioner compressors too close (C) Daniel Friedman

These four air conditioner compressors were found jammed into a wall niche along a street in Queretero, Mexico.

These units may have a short life before needing replacement.

Where there simply is not adequate space to provide proper air circulation around an air conditioning compressor or multiple compressors, it may be a good idea to let the building owner know that the units won't have a long life.

Reader Question: A/C condenser unit clearance to kitchen exhaust vent

(Oct 19, 2015) Gary said:
Is there a specific clearance for an exterior downdraft kitchen vent on the exterior wall to the condensing unit ?


OPINION: While we can't anticipate every crazy installation of stuff on or around buildings (people are very creative), there are possible hazards that I can imagine, so I'd like to see 48", principally because I don't want kitchen grease accumulating on the top of the condenser;

Watch out: there could be a more subtle hazard, even a fire hazard: if the compressor/condenser unit's exhaust is upwards out of the top of the unit (as is often the case) and if it blows up into the air intake of the kitchen exhaust fan while that fan is "on" (such that that fan's outlet baffle is normally blown-open by the kitchen fan) the strong blast of upwards air out of the A/C condenser unit may either close off the kitchen exhaust fan outlet baffle or it might even blow backwards back into the kitchen, risking grease accumulation in the kitchen exhaust, backdrafts, odors, even a fire.

Reader Question: minimum required distance between a home A/C condenser unit and a fill valve for a home heating oil tank

2015/11/06 Tom said:
what is the minimum required distance between a home A/C condenser unit and a fill valve for a home heating oil tank?


Fair question, Tom but I don't know. I've not seen a specific standard for that distance and doubt one exists. In general the condenser ought to be far enough away from the fill and vent valves that there is

- good working space around the condenser unit for maintenance and repair as well as adequate distance from the house wall so as not to obstruct air flow (shown in the article above)

All of that is subjective, but giving the delivery person several feet (3+) ought to be enough in my opinion.
- easy access for your oil delivery driver so she doesn't have to squeeze in between the condenser unit and the wall to reach the fill pipe or listen at the vent pipe; giving plenty of room here for a person to walk and drag a hose also reduces the chance of a splash of waste oil from the nozzle onto the AC unit.

Reader Question: impact of the A/C compressor unit on nearby indoor rooms

(Jan 29, 2014) David Kutil said:
is it possible that having 2 heat pumps next to the house could cause a room to be too cold or too hot? The room next to the two units is always too cold in winter or too warm in summer compared to the other rooms in the house. We were wondering if the air coming off the heat pumps against the side of the house would cause this. The heat pumps blow air up and we can see that the air hits the windows on that side of the house.



I don't think so. It's true that blocking air flow across a heat pump will limit its effectiveness, but I'd be surprised if that showed up as a difference between rooms in the home.

Your question is a good one but I'd be surprised if we could see an indoor effect from air exiting the heat pump.

Use the CONTACT link to send us photos of the installation and I may be able to comment further.

Rule of Thumb Vertical A/C / Heat Pump clearance distances: 4 ft. overhead free space

AC compressor air flow (C) InspectAPedia

In our sketch above you can see typical air flow patterns from an outdoor central AC compressor/condenser unit. Air enters at the sides and exits at the top of this unit.

So obstructing airflow out at the unit top will also reduce air flow across the condensing coils, shortening equipment life and cutting its efficiency. A rule of thumb is to assure that there is at least 4 ft. above the A./C compressor/condenser unit.

For example, installing an A./C or heat pump compressor under an outdoor deck might block its airflow (not to mention the noise aggravation). In fact typical A/C or heat pump installation instructions recommend that you locate the unit away from windows, patios, decks, etc., where unit operation sound may disturb the customer.

Reader Question: deck interferes with air circulation around the compressor unit

(Dec 2, 2014) steve wilson said:
Will an outside compressor unit get enough air circulation if there is a deck built over it?


Maybe not, Steve. The manufacturer probably specifies a minimum number of feet of clear space above the compressor/condenser unit to avoid restricting its intake or more often outflow.

For example, Lennox air conditioner installation instructions for the compressor/condenser unit typically require 48" of clear space above the unit.

Not to mention people

Possible A/C or heat pump Clearance Distance Exceptions

Photograph of a tipping air conditioning compressor

The most important clearance distances to respect around an outdoor air conditioner or heat pump compressor/condenser unit are with respect to those sides of the equipment through which air is intended to flow - either "in" to the unit our "out" of the unit.

Some outdoor units use a top mounted fan that blows "up" out of the unit, drawing cooling air through the condensing coils at one or more sides of the equipment. For these units both side clearance and top clearance must be respected.

But often the condensing coil does not extend through all four sides of the unit. If this is the case, the distance clearance from the side of a unit through which no air is expected to flow is probably less critical - though you should still be careful that multiple units placed too close together are not competing for the same air.

In our photo above, air moves into this compressor/condenser through three of its sides, but its "back side" (facing the building wall) is not one through which air moves.

Air Conditioning & Heat Pump Equipment Maximum Distances From a Building

Moving an air conditioner compressor to a distance of about 40 feet from a building won't prevent it from working, but the installer might need to adjust the diameter of the refrigerant lines to be sure that the equipment is working at 100% of its capacity.

it's not that the air conditioner won't work at all if the compressor/condenser is located at an unusual distance from the air handler/evaporator coil, it's more that it may lose some capacity and have to work harder - meaning higher electrical bills and in extreme cases, shorter equipment life.

Some air conditioner manufacturers such as McQuay provide a refrigeration piping guide that gives complete, detailed guidance and charts on refrigerant line sizing (diameter) as a function of length of run.

Details about refrigerant piping diameters, distances, and effects on equipment operation are

Continue reading at COMPRESSOR / CONDENSER INSTALLATION ERRORS or select a topic from the More Reading links or topic ARTICLE INDEX shown below.




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