There are few things more frustrating on a hot summer day than running an air conditioner that can’t keep up with cooling your space. The cause of the inefficiency may range from a simple maintenance task that has gone overlooked for too long, like changing out a dirty filter, to a more serious problem, like a refrigerant leak, that requires a visit from an AC repairman.
Your windows are the source of much of the heat that invades your home during the summer months. Even the highest quality windows can’t completely insulate your home from the extreme temperatures outside, but older windows are especially problematic.
If you are having trouble keeping your home cool, try closing the blinds during the hottest part of the day. If you are still having problems, you might want to install blackout curtains, which work well to block out both light and heat. If you’re interested in a more permanent solution that allows you to enjoy the sunlight, then you might want to invest in some double or triple pane windows that provide much improved insulation.
The evaporator coils and condenser coils on your outdoor unit need plenty of airflow around them in order to do their job properly. That’s why, as a general rule, you need to keep all plants, shrubbery, and flowers at least a few feet away from all sides of your unit.
Dust, dirt, leaves, and pollen can build up on these coils, which is why it’s a good idea to either have a technician clean them off during your seasonal tune-up or occasionally rinse the outdoor unit off yourself with a gentle flow of water.
Sometimes it’s not that there is anything wrong with your system. In extreme cases, it might be that your system is just not powerful enough to cool your home efficiently—or, as they say in the AC industry, “undersized.” Other times it’s unusually hot (much higher than the average temperature) and your AC system was simply never meant to deal with that much heat.
Air Filter is Dirty
One potential cause of a unit that won’t cool sufficiently is a dirty air filter. If the air filter becomes clogged by dust, pet hair, and similar debris, then there isn’t enough air flow for your air conditioning unit to keep your house cool. You should check your manufacturer guidelines to find out the size and type of filter you need, and follow recommendations about how often to clean or replace your air filter. It’s a good idea to try changing out your air filter to see if that helps before calling out a repairman.Windows

Insulation
Insulation keeps the cold out of your home during the winter, but not everyone realizes that it also keeps the cool air in during the summer while protecting your home from the hot temperatures outside. Poor insulation can make it extremely difficult for your air conditioning system to keep your house at a comfortable temperature.Thermostat
Your thermostat senses the temperature in your home and turns the AC unit on to maintain the temperature setting you’ve indicated. Most AC experts recommend that you set the fan to AUTO instead of ON. On AUTO, the fan only comes on when the AC comes on; if it’s set to ON, the fan blows all the time and will be blowing warm air when the AC isn’t on. If the thermostat has a low battery or, worse yet, a dead battery, it won’t be able to function properly. If you see a “low battery” indicator, then try replacing the batteries. If the problem isn’t a low battery, make sure the thermostat is set on a lower temperature than the outdoor weather. Sometimes thermostats malfunction and need to be replaced, a task that an AC technician can easily accomplish if necessary.Your Outdoor Unit

Leaking Ductwork
If your ductwork has developed some serious leaks, then your air conditioning unit won’t be able to keep your home cool. When you have leaky ductwork, the cool air that’s supposed to keep your rooms cool ends up going to unoccupied areas of the home, like the roof or your walls. An AC technician can use a non-toxic smoke to track down any leaks in your ductwork and then repair them for you.Refrigerant
Refrigerant is essentially what absorbs the heat from the air in your home. If your system doesn’t have enough refrigerant (often referred to as a charge), then it simply can’t keep your house cool on especially hot days. You may feel comfortable at night or early in the morning, but you’ll notice that it just can’t keep up in the heat of the day. Refrigerant leaks are not uncommon, and AC technicians can check refrigerant levels, find and fix the leaks, and then add the necessary charge of refrigerant needed for your system.Other Potential Problems
