How to make your Air Conditioner more Efficient



Posted: Tuesday, June 01, 2010

by Donald Grummett
http://www.mgservices.ca

Here are a number of ideas to help you get the most bang for your buck' from your window air conditioner.

1 Clean Filter

This is a very obvious suggestion but also a very important one. Once the air conditioner is installed and running it's something many of us simply forget to do. Remove and clean the filter every week during the operating season. Also brush off any accumulated debris near the front of the air conditioner. If required soak filter in few inches of hot water to which has been added a small amount of laundry detergent. Rinse thoroughly and allow to dry before reinstalling into the air conditioner.

Remember that although the filter captures debris from the room its primary job is to protect the cooling coil located at the front of the machine. Any dirt or debris entering here will coat the coils and drastically reduce its ability to pick up room heat, thereby lowering the cooling effect. Therefore keep the filter clean to keep up the efficiency.

2 Properly Levelled

Level is not a correct description when referring to window air conditioners. In fact they must be installed so that the rear of the machine is approximately 1-inch lower than the front. This slope allows water collected by the cooling coil to flow through channels in the base and then into rear. Once at the rear the moisture is allowed to drop out of the base onto the ground.

Since removal of the room moisture is what produces most of the cooling effect within the air conditioned room, then proper installation is critical.

Try not to exceed this 1-inch drop because water collecting in the base must not be allowed to run out too quickly. The water in the base has a purpose -- it's used to cool the condenser coil (the radiator-like device at the rear). Every time the fan motor turns water from the base is picked up by the fan blade and thrown onto the hot condenser. This will lower the condensers surface temperature and make it transfer the maximum amount of heat. Therefore proper levelling will result in a more efficient air conditioner.

One of the reasons people may lower the rear too much is in an attempt to eliminate the splashing noise made by the water accumulating in the base. People will often associate any unusual noise with something malfunctioning. Therefore they lower the rear of the air conditioner and force out the water until the noise ceases. Never do this the splashing noise is simply an indication that the air conditioner is working well.

3 Raise Thermostat

Again, this one is common sense. If operated at a warmer temperature the air conditioners overall run time will be less, resulting in less electricity consumed.

4 Ambient Temperature

Be aware that as your body encounters most temperatures your brain tries to make your body adapt to the new environment. The simplest way to express this is that, your brain will try to convince your body that any temperature it finds itself within is normal'. This is how we adapt to cold of the winter or the heat of the summer. So a strange adaptation can occur when we occupy an air-conditioned room. Over a period of weeks your body may become used to working in an air-conditioned environment. As the cooling season continues this can result in you wanting to operate the air conditioner at an increasingly colder temperature. Even to the point that what you may feel is a warm room temperature would seem too cold to someone who doesn't have air conditioning. Therefore use a room thermometer as your guide rather than what your body feels. Otherwise you will be tempted to keep increasing the temperature adjustment to make the room progressively colder which will increase run time and lower efficiency.

5 Turn Off

Turn your air conditioner off whenever you're not occupying the room especially if you leave the room for an extended period. There is a common fallacy that when you leave the room for a long period its more energy efficient to lower the thermostat to minimum and keep the air conditioner operating. This is false. Even setting it so that only the fan is operating will result in needless electrical consumption. Therefore if you wish to raise efficiency turn the air conditioner off whenever you leave the room. Even if the room becomes very warm while you're away it will only take a few minutes for the air conditioner to cool it down again once it's restarted

6 Turn off during bad weather

Modern window air conditioners often have electronic touch pads or computers. Both are prone to failure if the electricity goes off during a thunder or lightning storm. Also, momentary fluctuations in the electrical service can cause power spikes that may harm delicate electronic components. When operating erratically or giving false readings these components can negatively affect efficiency. Therefore we always suggest turning off (or even unplugging) window air conditioners during a storm.

7 Watering the condenser

I have had inquiries about doing this therefore I feel I should respond to this silly idea. Attaching a lawn hose to the rear of the air conditioner and constantly running water across the condenser will actually make the air conditioner more efficient. But it's another common myth that's actually a really bad idea. Both the cost and waste of water involved with this method should prohibit it from ever being considered. Plus, running water through electrical machinery is so dangerous that it should never even be suggested.

8 Sunlight into room

Direct sunlight through your windows will warm up the room making the air conditioner run longer and consequently lower its efficiency. The simple act of closing drapes or lowering blinds can help cure this problem.

9 Shading rear of air conditioner

Natural shading occurs on the northern or eastern sides of your house and will result in a more efficient air conditioner. This is something to consider when deciding which window opening to place it into. It's something that costs nothing and yet most people don't even consider how much placement can contribute to efficiency. Direct sunlight striking the rear of your air conditioner will make it work harder by overheating the already hot condenser coil. Therefore shading the rear area allows the condenser to give off its heat quicker which will raise its efficiency. Other authors suggest the addition of an awning or planting a tree to shade the rear of the air conditioner. Shading your air conditioner by these methods is usually not practical because the money spent will not be recouped by any resulting increase in efficiency.

By Donald Grummett

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Top-level comments on this article: (1 total)
» left by Gadgeteer from NYC 1 year 344 days ago.
#7 is not entirely correct.
 
Commercial AC does run water over the condenser, thought not in nearly the quantity you'd have by blasting a garden hose over a window AC.
 
There have been residential water cooled units for many years for use in very hot areas. There is also a kit made to create a fine mist at the intake side of the condenser, which includes a water softener to prevent mineral buildup, and a valve the activates only when the condenser fan is running. This kit is normally used for central AC but would work if installed appropriately window unit - you'd want to insulate the hose to prevent it from dispensing _hot_ water, etc. Very little water is needed, as the idea is not to put the coil in a water bath, but to use evaporative cooling so the coil sees cool, mist-laden air.
 
As for the electrical issue .... common window units today have vents in the top, and the side vents open _upward_ to deliberately collect rainwater. Excess overflows to the outside, it's not a boat and the water can't rise to approach the electrics. Better take it back to the store if you're worried about water inside!  Mineral scale, mold and water waste will be issues with the garden hose method but all can be addressed with a little thought.
 
So, just pointing a garden hose at your AC is "clever" but not quite smart. But a refinement of that idea does work, especially in hot climates.
» left by Anonymous 1 year 343 days ago.
Thank you for your input. I'm glad we agree that using a lawn hose to cool your window air conditioner is not "very smart". Being a HVAC mechanic myself I understand your evaporative condenser scenario but this article is written for the average householder with none of our experience. Plus, with the average 8000 BTU unit costing less than $200 the addition of a water spray system would seem to be somewhat uneconomical.
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