Improperly Sized Systems
When it comes to air conditioners, bigger is not necessarily better. In fact, an oversized air conditioner will constantly cycle on and off, leading to inefficient power usage and uncomfortable temperature changes. Of course, an undersized air conditioner is just as problematic; without enough cooling capacity, your unit will wear itself out quickly and fail to keep your room as comfortable as it could. Either case is a sure ticket to an expensive AC repair down the road.
If you need a new air conditioner, make sure your contractor does a complete load calculation to determine exactly how much cooling capacity your home needs. By taking square footage, layout, insulation and load-generating appliances into account, your HVAC professional can find your home's cooling load and recommend an air conditioner that is perfectly sized to meet that cooling need.
Incorrect AC Positioning
The location of your air conditioner has a big impact on its energy efficiency. While it may seem convenient to put your bulky HVAC system in an unused corner on the west side of the house, that placement will force the machine to work harder to cool your home. Instead, find a shady spot to put the air conditioner; the less direct sunlight it gets, the less power it will need to cool your home. Remember that window-mounted air conditioners should also be tilted back slightly to allow for proper drainage.
In addition to being positioned in the shade, your air conditioner shouldn't be blocked in by shrubs or other objects. As unsightly as it may be, leaving the outdoor unit free to breathe will improve ventilation and help it run more efficiently. Finally, make sure the thermostat is positioned away from lamps and other appliances that create heat; if the thermostat gets too hot, it may incorrectly control your air conditioner.
Running AC 24/7
It may seem easy to just let your air conditioner run full blast all day long, but doing so wastes a fair amount of electricity. If the room is going to be empty for most of the day, turn the thermostat off before you leave and then turn it on again when you return. Your air conditioner system needs only a few minutes to cool your room, so you won't sacrifice much comfort by doing so.
Likewise, it can be a good idea to shut your air conditioner off overnight. Your body can tolerate higher temperatures when asleep than when awake; moreover, leaving your AC unit idle as temperatures fall helps to prevent freezing up in the morning. Consider investing in a programmable thermostat to take the work out of this temperature manipulation.
Incorrect Thermostat Settings
If you get into your room and want the air to get cooler right away, don't turn the thermostat way down and expect your AC unit to work faster. For instance, if you are comfortable at 77 degrees, don't set the thermostat to 70 in an effort to reach 77 quickly. In reality, your air conditioner will skip right past the desired temperature, wasting energy in the process, and you will find yourself even more uncomfortable as the temperature shifts rapidly.
As a rule, you should set the thermostat as high as you are comfortable; for most people, that spot is somewhere between 76 and 79 degrees Fahrenheit. Remember, every degree makes a difference of about 7 percent in your unit's power consumption, so even a small adjustment can make a big difference on our monthly utility bills.
Not Using Ceiling Fans
Many people think of air conditioning as a substitute for a traditional ceiling fan; in fact, these two HVAC systems are designed to work in concert. A ceiling fan helps your air conditioner run more efficiently by moving air around the room, which not only saves money on your utility bills but also reduces wear and tear on the AC unit itself. Furthermore, a good ceiling fan creates an artificial "wind chill" effect that helps you feel comfortable at slightly higher temperatures.
To get the most use out of your HVAC system, look for an Energy Star rated ceiling fan, and be sure to put it in the down-flow setting during the cooling season. Some fans can be reversed during the heating season to help your heater run more efficiently, too.
Not Changing the Air Filter
The air filter is the essential component of every air conditioner that removes dust and debris from the air before it blows into your room. Inevitably, air filters become clogged with dirt as the air conditioner operates. Most air filters need to be cleaned or replaced on a monthly basis, although some high-efficiency filters can last a little longer between cleanings. Dirty air filters can reduce system efficiency and lead to problems such as freezing.
If your air conditioner has a reusable filter, be sure to wash it in cold water and let it air dry completely before putting it back in the unit. Trying to wipe off the air filter can damage its delicate dust-trapping surface.
While your air conditioner is running, leaving doors and windows open reduces its operating efficiency and undermines your HVAC system's ability to bring your room to a comfortable temperature. Whether you're letting hot air into your room during the day or bringing in cool air at night, the air conditioner system has to fight even harder to pull the humidity out of the air and cool your room down. When the air conditioning is on, please keep all windows and doors closed.
A closely related mistake is using exhaust fans in the kitchen or bathroom. These fans can push conditioned air out of your house, which needlessly increases the strain on your air conditioner. During the cooling season, use these fans as sparingly as possible.
Not Providing Routine Maintenance
Air conditioners may be able to run on their own for extended periods of time, but they need occasional maintenance to operate at maximum efficiency year after year. At least once per cooling season, have a HVAC maintenance technician check your unit for any emerging issues that could call for an expensive AC repair down the road. An HVAC professional can also make some small calibration adjustments to improve your unit's energy efficiency.
Between professional maintenance checks, you can also help preserve your air conditioner by providing good home maintenance. Changing the air filter regularly is an important step, of course, but you should also check the window seals, run a stiff wire through the drain channels and check the refrigerant gauge to identify any emerging issues. A little prevention now will save you plenty on AC repairs later.
Not Fixing Emerging Issues
Especially in the middle of a busy day, it is easy to just let a rattling sound or frequent cycling on and off slide. In reality, these visible or audible issues are usually signs of bigger problems lurking just beneath your air conditioner's cover. Your air conditioning unit represents a significant investment in your comfort, so protect that investment. At the first sign of trouble, check your unit for any signs of significant problems, and be ready to call an HVAC professional to take a closer look.