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.
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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 photoat page top these two compressor/condenser units are too close together as well as too close to the building walls.
Air Conditioning & Heat Pump Equipment Minimum Clearance Distances from Building Walls, Shrubs, Other Equipment
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 operasting costs (for the same reason - hotter opeating temperature means lower efficiency during the cooling season).
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 veed 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.
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
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 Infinitiy Series Air Conditioner of 2-5 nominal ton size A/C equipment installation manual:
General working space around the compressor/condenser
When installing, allow sufficienit 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.
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
Keep shrubbery trimmed away from the unit and
check for debris which collects around the
- Lennox Corporation, "Installation Instructions, Elite® Series XC13 Units, Condensing Units 506635-01" (09/2011), retrieved 12/2/2014, original source: https://www.lennox.com/pdfs/installation_maintenance /Lennox_XC13_IOM.pdf
Other building mechanical systems that would interfere with the heat pump or air conditioner compressor-condenser unit
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.
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.
Do not locate the outdoor HVAC compressor/condesnerr unit where exhaust from a direct-vented heating appliance will blow onto the unit.
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.
Rule of Thumb Vertical A/C / Heat Pump clearance distances: overhead free space
In our sketch (left) 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 insturctions recommend that you locate the unit away from windows, patios, decks, etc., where unit operation sound may disturb the customer.
Possible A/C or heat pump Clearance Distance Exceptions
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 thorugh 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.
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Lennox Corporation, "Installation Instructions, Elite® Series XC13 Units, Condensing Units 506635-01" (09/2011), retrieved 12/2/2014, original source: https://www.lennox.com/pdfs/installation_maintenance /Lennox_XC13_IOM.pdf
 Carrier Corporation, "24 ANA Infinity™ Series Air Conditioners with Puron® Refrigerant, 2 to 5 Nominal Tons (Sizes 24 to 60), Installation Instructions", Carrier Corp., 7310 W. Morris St., Indianapolis MN 46231, 2009, for Carrier A/C models 24ANA7 and 24ANA1 units.
 Thanks to reader (Anon)
for discussing the allowable distance between air conditioner compressor and a building or from the air handler - July 2010
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