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tips to keep your home air conditioner working smoothly

Air Conditioning is an essential part of life nowadays, and anything of real value needs utmost care and attention. Are there hot and cold spots in your air-conditioned room? Do you have pressure imbalance - strange whistling noises, doors closing by themselves, drafty areas - anywhere? Are you getting little to no air coming from your AC? Is your AC blowing warm air? Now that spring is here, it is the perfect time to take a look at your air conditioner and plan for any updates that might be needed - before the summer rush!

These are common AC problems that you may be able to troubleshoot yourself. Common causes are remarkably simple, so even basic care and a tiny bit of DIY can help. Let’s talk about these common problems a little bit more.

Keep the Air Filter Clean

Air filters are an important part of a ventilation system. You’d be surprised how many problems a dirty filter can cause - from warm air blowing through your house to ice on your unit to blown circuits.

Filters help block airborne particles like molds, bacteria, viruses, pollen, and dust. But if the ducts are clogged, this impairs free airflow. A clogged-up filter starves your AC unit for much-needed air.

AC units with dirty filters have to work harder to provide the needed temperature. In the worst-case scenario, the AC will be unable to deliver at all. Overworked units result in higher utility bills. Also, when the air is inhibited from flowing through the ductwork, it backs up into the air handler and causes the condenser to freeze over.

If you find ice on the condenser (the outside unit) and you’re not getting cold air inside, chances are your filter is at fault. Filters are designed to catch and keep dirt, dust, pollen, and any other debris from getting into your home ventilation. When the filter is full of caught debris, it gets clogged up and restricts the air in the system.

A clogged filter wreaks havoc on your AC unit. It may affect the coils, motors, and blowers of your HVAC system.

So the primary purpose of the air filters is to protect the AC unit itself. But faulty filters may also pump your home full of dust and allergens. These can cause physical symptoms such as headaches, fatigue, tightness in the chest and other cold-like symptoms that will persist until you clear up or change your AC’s air filter.

How frequently you need to change your air filters may depend on the type of air filter your system requires, overall indoor air quality, pets in the home (and how many), occupancy, and the levels of air pollution around the home. Here is a general guideline on when to change your air filters:

  • Vacation home or single-occupant with no pets and no known allergies: once every 6-12 months
  • Suburban home with no pets: once every 90 days
  • With a dog or cat: once every 60 days
  • More pets and/or known allergies: once every 20-45 days

Changing a filter is a remarkably easy step to take. Just be sure to follow a schedule and to use the appropriately-sized filter for your unit. A filter that’s too small is going to let all those contaminants go right past it. There are both disposable and reusable filters available.

Checking on the Outside Unit

Another thing you need to do to ensure good HVAC airflow is to clear the area surrounding your condensing (or “outside”) unit. Outdoor units can become obstructed by accumulated leaves and debris. Even condensing units situated inside mechanical rooms can be obstructed by stored equipment or furniture. Your system can overheat when its access to air is curtailed.

Air conditioners pump refrigerant throughout the system in a cycle that runs from hot to cold, and the hot air needs a place to exit. That is the main function of the outside unit. So when you’re doing the yardwork, just check around the condenser for grass clippings, leaves, or trash that may be impeding airflow. A thorough check once a year is great, but you can keep it simpler with a  regular check while mowing the lawn or shoveling snow.

An occasional cleaning of the vents and ductwork helps, too. You might need a pro to do the job thoroughly, but regularly dusting the vent covers and even occasionally popping them off and checking inside can be a help to keep the air flowing.

This might seem overly obvious, but we’ll say it anyway: make sure all vents and registers are free of obstructions from your furniture. This kind of blockage can keep the system from working as designed, and cause uneven cooling and higher bills. There are various zoning options to improve your HVAC system that can more adequately address these needs.

Follow Your Nose

A common indicator that something is amiss within the vents and ductwork of an AC system is foul odors coming out of them.

A “rotten egg” odor may indicate that you have a dead animal in your ductwork. Birds or rodents or other small animals often make their way into the system through the furnace ventilation system. Of course, you can look yourself and try to pull out any remains yourself. If you can’t find it, call a pro.

A “dirty sock” odor may show up when the moisture in the system allows mildew to grow on your system’s evaporator coil. The best possible solution is to have your evaporator coil, condensation system, and the ductwork cleaned. You might be able to do a basic job yourself on this; there are numerous anti-mildew chemicals available.

Just be aware that getting the evaporator coil and condensation pan clean may only eliminate the smell for the short term. It could just be that the system and environment together are prone to this. If you have a recurring problem, talk with a contractor. There are several options, including a special coating for the condenser or UV-C lights that can kill the mildew.

Have Regular Maintenance Done

Basic care can go a long way to keeping your system running right and keeping you as cool as you want to be. Of course, there are things beyond the scope of these DIY care and maintenance solutions.

A professional HVAC contractor will understand exactly how your home’s system works. They don’t only maintain your units but can be a huge help in optimizing your system for performance and efficiency. A yearly visit from a pro will go a long way to preserving optimal function.

Remember, too, that certain aspects of your AC like charging refrigerants need to be dealt with by licensed professionals.


As tragic as a problematic air conditioner may seem to be, don’t fret. A majority of AC issues are caused by simple factors. You can often figure out and fix the source of the trouble yourself with a few simple steps and regular care. If it’s beyond you, there are plenty of reputable contractors around. But being able to do some basic troubleshooting yourself saves money and gives that sense of pride that only comes from handling issues personally.


This is a guest post by Bob Wells, a retired HVAC tech who now dedicates himself to sharing knowledge on his website HVAC Training 101. Bob worked over 30 years in the field, 23 of which he ran his own contracting business. He’s dedicated to keeping up with the latest developments in the field and helping others to learn the trade better and advance their own careers.

Bob is on Twitter with the handle @hvactraining101 and you can also find him on Facebook.