Outdoor Unit Air Flow Issues – A Deep Dive
Your air conditioner won’t work correctly if there is a lack of airflow around the outdoor unit. In Winter the unit has to absorb heat from outside to heat the air inside your home, in Summer the unit needs to expel heat that has been removed from inside your home. Without the ability to move high volumes of air from the outdoor unit, your air conditioning outdoor unit will have serious performance issues. Performance can drop over 50% with inadequate ventilation and this is worse when the ambient temperatures are very low and very high. If the outdoor unit is installed close to a fence or wall, the air blows against the fence and bounces back towards the unit. This air recirculates around to the back of the air conditioner unit causing the refrigerant coil to freeze in Winter and overheat in Summer.
Problematic outdoor airflow issues include:
- Fence, wall or obstruction within 2m of the front of the air conditioner
- One or multiple units blowing air into the back or side of another air conditioner
- Multiple air conditioners blowing towards each other (especially if they are offset)
- Dense trees, shrubs in front of the air conditioner can prevent proper ventilation
- Rubbish stored behind the air conditioner can hinder airflow
- Pet hair and dander can clog the outdoor coil, preventing airflow
- Outdoor units installed on a balcony or within entertaining areas can cause unwanted air blowing on guests
Fence, wall or obstruction within 2m of the front of the unit
The best way to overcome front obstructions such as a fence or wall is to relocate the air conditioner. The new location should be well ventilated and the outdoor unit installed with adequate distance between the front of the unit and any obstructions such as a fence or wall. The specific distance depends on manufacturer specifications but keeping a minimum of 2 meters will ensure no issues. If the cost to relocate the unit is high or there are no locations around the property that are suitable, the only other option is to install a deflector on the front of the outdoor unit. Magnetic deflectors are available and provide a DIY solution that is removable to allow access when required.
One or multiple units blowing air into the back or side of another unit
If two or more air conditioners are blowing into each other, in Summer the hot air from one unit will be sucked into the other unit, causing the front unit to overheat. In Winter, the rear unit blows cold air and the front unit will freeze. As with the outdoor unit near a fence or wall, the best way to overcome other units blowing into your air conditioner is to relocate one or more of the problematic units. If units cannot be relocated to a suitable location, a deflector should be installed to the rear outdoor unit to stop air blowing into the front outdoor unit. Magnetic deflectors are available and provide a DIY solution that is removable to allow access when required.
Multiple units blowing towards each other (especially if they are offset)
This issue is particularly common in apartment, townhouse living and independent living villages. With multiple air conditioners installed close together, often the units are blowing towards each other. If the units are close or down an alley between houses, this causes each unit to blow air into the opposite unit. Both units recycle the other units air and cause freezing and overheating issues, drastically reducing unit performance. If the units can be installed in a better location, this is the best fix. If this is not possible, a deflector installed to both units is required. If only 1 unit has a deflector installed, the unit without the deflector is now ok but the unit with a deflector is still suffering performance loss until the opposite unit has a deflector installed. Magnetic deflectors are available and provide a DIY solution that is removable to allow access when required.
Dense trees, shrubs in front of the unit can prevent proper ventilation
As we have covered above, outdoor unit ventilation is important to ensure correct operation and performance of your air conditioner. If the front or sides of your air conditioning unit is overgrown with trees, shrubs or bushes, it can act like a barrier and prevent adequate ventilation. Ensure the plants are cut back and thinned out to allow airflow from your air conditioner. This can also help prevent bugs, lizards, snakes, spiders and mice from making a home within the outdoor unit.
Rubbish stored behind the unit can hinder airflow
Most air conditioning units installed in Australia will draw air through the coil at the back of the unit and then blow the air out the front of the unit. If there is rubbish such as boxes, tools, cardboard or plastic etc stored behind the unit, the amount of available air is reduced. This causes the unit to freeze in Winter and overheat in Summer. Keeping the space behind the unit clear is a very important factor to ensure correct operation of your air conditioner.
Pet hair and dander can clog the outdoor unit, preventing airflow
This is a common problem, especially with a large, hairy dog living outside. We have often found a mat of dog hair against the back of the air conditioner coil. This acts like a blanket over the coil and dramatically reduces airflow and performance. This can be removed with a dustpan brush or by hand. Ensure you wear gloves to prevent any cuts from the coil. If the hair has become ingrained within the coil fins, you may require a professional clean from the inside out. This is often done with a foam cleaner which expands and pushes the hair outward.
Outdoor units installed on a balcony or within entertaining areas can cause unwanted air blowing on guests
Not all airflow issues affect performance, sometimes your entertaining area is subject to unwanted airflow from your air conditioning outdoor unit. Outdoor units installed on a balcony or within an entertaining area can cause discomfort as unwanted air blows at your guests. One solution is to relocate the outdoor unit to a new location, this is the best way to prevent unwanted air in your entertaining area. If relocation is not possible or practical, another solution is to install a deflector onto the unit and divert the air away from the entertaining area. A deflector can deflect the air at a 45 degree angle, either upwards or sideways, away from your entertainment area. Magnetic deflectors are available and provide a DIY solution that is removable to allow access when required.
In a nutshell
- Outdoor unit airflow has a massive effect on the efficiency of your air conditioner
- Outdoor airflow issues are worse when the ambient temperature is very high or low. Often the issue is not noticed as easily during mild weather
- Most issues can be identified by the homeowner
- Professional advice is required to relocate an air conditioning outdoor unit or clean the coil from the inside
- If a unit cannot be moved, a defletor is recommended. Deflectors can be installed DIY, especially our magnetic removable deflector found here
