29 Air Conditioner Tips to Optimize Your AC and Lower Your Energy Bill

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Air conditioners are a luxury that most people don’t give a second thought until their unit breaks down or their monthly energy bills skyrocket — man AC accounts for more than 10% of annual energy costs, which could be a lot higher on hot summer days.

Fortunately, there are easy, low to no-cost ways to optimize your air conditioning and reduce costs. To prevent your air conditioner from sputtering out during the hot summer and decrease your energy costs, follow our detailed maintenance and efficiency air conditioner tips below.

a man inspecting an air conditioner

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1. Set the Ideal Thermostat Setpoint

Set your ideal temperature on your thermostat and let it be. Don’t change it back and forth just because you’re feeling a little too hot or too cold. Instead, add or remove clothing layers to get comfortable, and your AC unit will thank you.

As a general rule of thumb, don’t set your AC unit lower than 65-70ºF. A great way to optimize your thermostat’s setpoint is with a programmable unit or a smart thermostat – the best ones are the Ecobee and Nest.

2. Unclog Your Vents and Ductwork

a person dusting the AC’s vent

A common HVAC problem in homes is low airflow which is caused by an obstruction in your vents and ductwork. If the supply and return vents in your home have clogs, this will reduce the amount of air that can flow through them.

Because of that, your AC unit will have to work harder and longer to supply cool air to your home and reach your thermostat’s setpoint.

Besides your vents becoming clogged with dust, hair, etc., your ductwork may form a buildup of these “dust bunnies,” too. Usually, it takes months to years to become a problem.

Most HVAC experts recommend cleaning your vents at least once a month and vacuuming out your ductwork every five to seven years (or sooner if you have lots of shedding pets).

Learn More: What is an HVAC System?

3. Turn Off Your AC at Night

In many areas throughout the U.S., the outdoor temperature is significantly cooler during the nighttime. If you turn off your air conditioning once the sun goes down and open some windows instead, you might see substantial savings on your energy bill.

Plus, since your AC unit will no longer be running as often, it will experience less wear and tear, which means you’ll deter repairs and maintenance associated with high usage.

Before you choose to turn your AC off at night, consider the outdoor night temperature and pollen. If the temperature or pollen count is forecasted to be high, opening your windows probably won’t be worth the potential energy savings.

Pro tip: if you have a programmable or smart thermostat, you can set your AC to turn on and off automatically based on the time of day or the outdoor temperature. However, these features depend on the specific thermostat model.

4. Turn off Heat-Emitting Appliances

Appliances that put off heat will make your air conditioner run longer. Why?

It’s because they’re heating your home—  the exact opposite of what air conditioners do!

Avoid using these common heat emitting appliances and electronics (if you can):

  • Stovetop
  • Oven
  • Tea kettle
  • Coffee pot
  • Computers and monitors
  • Televisions
  • Lights

So, by limiting your usage of these appliances and turning them off promptly when not in use, you will not only save energy by using them less but also by optimizing your air conditioner’s cooling too.

​​5. Replace Your Light Bulbs

a person installing a LED light bulb

If your home has fluorescent, incandescent, and halogen light bulbs, consider replacing them with LED bulbs. LED bulbs produce up to 80% less heat and use over 50% less energy than traditional light bulbs.

Yes, you’ll have to fork over some money to replace all your old light bulbs with LED versions, but you’ll have a quick ROI (return on investment) through your monthly energy savings.

6. Turn Off as Many Lights as You Can

Since even LED light bulbs add heat to your home, turning off the lights when you leave a room can help reduce your energy costs two-fold.

You save on the electricity from the lights being off, plus it reduces how often your AC unit runs, which could be substantial.

7. Replace the Filters

a hand pointing to an AC filter with thick layer of dust

Your HVAC air filter, whether you have a MERV 13 or HEPA filter, will negatively impact your air conditioner’s performance as it gets dirty. Your HVAC filter is designed to capture dust, hair, pollen, mold, viruses, and other pathogens, but it doesn’t last forever.

You have to change it; otherwise, it will get so dirty that it will block airflow, resulting in increased cooling cost and damage to your AC unit if you go too long with changing it.

Note: How often you should change your filter depends on the type of filter and the condition of your home, but the rule of thumb is to change it out once every six months. Read our full guide here.

Some filters can last up to a year, but if you have lots of furry pets, you may have to change your filter more often than twice a year.

Check for a clogged filter once every month or so and replace it if it looks dirty— you’ll know when to replace it when you see a thick layer of dust on it.

8. Clean the Condensate Pan and Drain Line

During regular operation, your air conditioner removes humidity from the air as it cools. This happens within your air conditioning system’s air handler (indoor unit).

When warm air blows across the evaporator coils (which contain cold refrigerant), heat transfers from the air to the refrigerant. The refrigerant gets warmer, and the air gets cooler.

And since warmer air can hold more moisture (humidity) than cooler air, water will condense out of the air as it cools. Typically, the water condenses directly on the evaporator coils. It then drips into the condensate pan, strategically placed directly below.

The water then drains from the drip pan into the condensate drain line, flowing outdoors or into your sump pit.

Condensate drain lines can get clogged from calcium buildup, algae, mold, or a mixture of all three. Usually, condensate drain line clogs are easy to fix by pouring vinegar or bleach into the pan.

But sometimes, you’ll need to use a shop vacuum (on the outlet) and a pipe cleaner to remove stubborn clogs. You should check your condensate drain pan at least once a year. It should never have standing water in it.

You should have your condensate pan and drain line clean and inspected every year too. When you have your local HVAC technician come out for your yearly AC tune-up, the condensate pan and drain line are on their inspection checklist.

Need a HVAC Expert?

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9. Clean the Coils

A HVAC professional cleaning an AC’s coil

Your air conditioning unit has two sets of coil:

  • Evaporator coils— located in the air handler inside your home
  • Condenser coils— located on the condenser unit outside your home

Your evaporator coils tend to get clogged with dust, dirt, and hair, especially if you don’t keep up with replacing your HVAC filter.

You can clean it yourself with a vacuum, some soap and water, and a soft-bristle brush, an air comb, or you can hire an HVAC technician to do it for you.

On the other hand, the condenser coils tend to get clogged with leaves, twigs, grass, dirt, and other outdoor debris. You can clean them the same way you clean the evaporator coils, but you can use a garden hose to help since it’s outdoors.

Trim back any vegetation at least three feet to help maintain the cleanliness of your outdoor coils.

You should clean your indoor and outdoor coils at least once a year. Coil cleaning is usually part of routine maintenance packages offered by many HVAC contractors.

10. Straighten Your Coil Fins

The coil fins in your air conditioner collect heat from the air in your home to cool it. They are basically a mesh-type metal grate that allows air to pass over your coils.

If they get bent, they will prevent proper airflow and reduce how effective your air conditioner can cool the air. The outdoor unit of your air conditioner also has coil fins that can get bent— the four “walls” of your condensing unit are almost entirely coil fins.

You can straighten the coil fins with a fin comb by “brushing” the fins along the grain. However, don’t push too hard, or you might damage them.

Fin combs generally aren’t available in hardware stores, but you can find them online. Alternatively, your local HVAC contractor will have some too, which they can sell to you or use themselves to straighten your fins.

11. Adjust the vents

Your HVAC system is designed to heat and cool your entire home. If your vents are blocked or obstructed somehow, that will reduce your air conditioner’s effectiveness.

So make sure they are fully open and no furniture or a misplaced blanket over the supply vents.

12. Close Windows and Doors

This might sound like a no-brainer, but keep your doors and windows closed, especially in the hot summer. Yes, it might feel good every so often to get some fresh air in your home.

However, keeping the doors and windows open for too long will make your AC unit work more and cost you more money.

13. Check Wiring and Other Components

Over time, certain electrical components of your air conditioner can wear down. You or your HVAC technician should verify that the wiring and other electrical components are secure once a year.

Checking the wiring and other electrical components is part of your annual AC inspection and tune-up. The HVAC technician will check:

  • Proper contactor function
  • Relays function correctly
  • Capacitor is normal (and not deformed)
  • Wiring is secure with no sparks

Related Article: The Best Battery Powered Air Conditioners

14. Have the right air conditioner size

a couple shopping for an airconditioner

If you’re upgrading your existing AC unit or building a new house, you should ensure you choose an air conditioner that is the right size. Air conditioner size is synonymous with cooling capacity and is measured in BTUs and tons. One ton equals 12,000 BTUs.

In general, the air conditioner size you need depends mainly on the size of your home and various other factors, such as:

  • Insulation
  • Floor plan layout
  • Natural shade from trees
  • Local climate

Note: Your home will need between 20 to 30 BTUs of cooling capacity per square foot of finished living space for the most part. However, it will vary based on the above factors.

To calculate the right size air conditioner for your home, an experienced HVAC technician can provide an exact estimate on the size you need by using a Manual J calculation on your home.

If you choose the wrong size, you’ll have lots of problems down the road. An AC unit that is too small will run constantly and never reach the setpoint on your thermostat.

On the other hand, an oversized air conditioner will cool your home too quickly and turn on and off frequently. This is known as “short cycling.” It is problematic because turning on and off often uses much more energy than running for longer intervals.

Additionally, short cycling doesn’t give your air conditioner enough “run time” to remove humidity from the air in your home. As such, a common symptom of an oversized AC unit is high humidity which can make you feel damp and uncomfortable. Plus, the humidity gives mold the perfect conditions to flourish.

Need a HVAC Expert?

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15. Use a High-Efficiency Air Conditioner

The efficiency of an air conditioner is measured in SEER (seasonal energy efficiency ratio). It measures the AC unit’s efficiency across the entire cooling season.

Note: AC units with higher SEER ratings are better and use less energy than non-rated counterparts.

They also provide better home comfort– the cooling they provide is more “even,” meaning your home will have fewer hot and cold spots. Plus, they have better humidity control.

Upgrading an existing air conditioner that still has many years of service usually doesn’t make sense financially. However, if you need a new AC unit, consider a high-efficiency system. But note that they will cost more upfront than a unit with a lower SEER rating.

16. Add Attic Ventilation and Insulation

a worker adding thermal insulation in the attic

If you don’t have good insulation and ventilation in your attic, you might be making your air conditioner work harder than it needs to. Typically, attics are connected to residential HVAC systems, which means they heat up and cold down based on the outdoor temperature. 

Adding extra insulation will ensure that the warm air in the attic doesn’t warm up the rest of your house and counteract your AC unit. Plus, adding passive or active ventilation will also help remove hot air from the attic.

17. Replace the Compressor Relay Switch

The compressor relay switch is located on your outdoor unit. It turns on and off the electricity to the compressor and controls when it runs and for how long. If it were to fail, your air conditioner would stop working, and your house would heat up until it is repaired.

To prevent a random failure and one to two uncomfortable days without air conditioning, most HVAC manufacturers recommend you replace the compressor relay once every 5 to 10 years, depending on the make and model.

18. Use Fans

Turn on a fan instead of lowering the setpoint on your thermostat when you feel hot. Whether you use a floor fan or ceiling fan, they will help circulate the cold air, and the breeze will help cool you down. Moreover, they use less energy than making your AC run longer. ​

19. Find Air Leaks and Seal

a person sealing the window

Many homes have air leaks or small holes and crevices that hot or cool air can escape. Air leaks can be challenging to find if you don’t know what you’re looking for. However, they are usually present around windows and doors.

More often than not, the leaks around windows and doors are due to bad seals or old gaskets. In this case, replacing the seals around the doors and windows can solve air leakages and optimize the efficiency of your AC unit.

You can find air leaks with a flashlight at night– see if you can see the light through cracks from the outside of your home. Alternatively, you can feel around the seams for changes in air temperature with your hands.

For small leaks, you can use felt, foam, rubber, or metal weather strips, and for larger ones, you can use polyurethane insulation foam.

Besides air leaks in the structure of your home, your air ducts could have leaks too. These you can seal up with some trusty duct tape.

Need a HVAC Expert?

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20. Cool Spaces that You Are Only Using

While a central AC unit is sized for cooling your entire home, you might be able to save money by only cooling only the part of your home you are currently using. But with a central AC system, this will only work if the thermostat is in the same room you are cooling. 

If you close off the vents to the room your thermostat is located in, it will get hotter than the rest of your house and continue to run the AC. This will make the rest of your home too cold and overwork your air conditioner. 
On the other hand, if your home has zone cooling with ductless mini-split systems, window AC units, or portable air conditioners, it is much easier to cool only the room you’re using.

Learn More: What is the difference between a mini-split and a central air conditioner?

21. Level the Air Conditioner Pad

Several AC units resting on a level air conditioner pad or base

The outdoor unit or condenser unit of your air conditioner sits outside your home on an air conditioner pad. The unit is designed to operate with the system being level. If it is not level, the fan and the compressor motor will be unbalanced.

When it is unbalanced, it will operate inefficiently and can cause the unit to break down completely. Plus, it will likely be very noisy when it runs. So, it is crucial to fix it as soon as possible.

How do you level a sinking air conditioner pad? There’s no quick trick or easy method. You have to remove the condenser unit and the pad, dig under it, level it with sand, then carefully replace the pad and outdoor unit.

22. Use Shades or Blinds

Unless you were born yesterday, you know that the sun coming in through your windows heats the room. If you’ve ever laid in a sunspot, you know this to be true.

As such, blocking out the light is a great way to reduce your cooling bill and take the stress off your AC unit.

Blackout curtains, shades, and blinds work best. You can close them when you leave for work or while you’re on vacation. This will keep your home’s indoor temperature more manageable throughout the day without relying too much on your AC unit.

23. Use Solar Screens or Tint Your Windows

Besides blackout curtains, blinds, and shades, you can invest in solar screens for your windows. 

Solar screens are desirable by many homeowners because they block out 65-90% of the UV rays, which reduces the heating effect (and use of your AC unit) but still allows some light to enter your home.

Along with solar screens, you can directly tint your windows for the same effect and benefits. However, tinted windows are permanent, whereas you can roll up solar screens when you don’t need them.

24. Plant Some Trees

Trees aren’t just visually appealing additions to your property; they can also provide shade to your home. If you plan to plant some trees to shade your home, do so strategically. Plant the trees on the south side of your home if you live in the Northern hemisphere since that’s the direction the sun rays will be coming from.

25. Add Shade to the Outdoor Condenser

Along with your home heating up from the sun, your outdoor condenser unit will too. If you’re building a new home, have your builder place your outdoor unit on the north side of your home (assuming you’re in the Northern hemisphere). That way, it will almost always be in your home’s shade.

However, if your AC unit is already installed, you can add shrubbery or trees nearby to provide shade. Or you can add a fence to block the sunlight.

Never wrap the outdoor unit (unless it’s winter and the AC unit is off). If you cover it in the summer, you will obstruct airflow and cause significant damage.

26. Turn Off Exhaust Fans

Exhaust fans are a great way to remove steam and odors from your bathrooms and smoke from your stovetop. However, they exhaust a ton of air directly outdoors that your AC unit worked so hard to cool.

Obviously, you can go without using exhaust fans indefinitely. However, you can remember to turn them off right after you don’t need them anymore. In other words, don’t leave them on for hours (or days) at a time.

27. Get a Dehumidifier

A dehumidifier could be necessary for homes in humid areas like Florida and the rest of the Southeast U.S.. Air conditioners remove humidity from the air when they cool it.

However,  if the outdoor air is too humid, the inside of your home will be too. When moisture is high indoors, mold and mildew can breed. Plus, it makes you feel wet and sticky.

Therefore, a supplemental dehumidifier can optimize your air conditioner’s performance and make your home more comfortable and safe (mold is a health hazard).

28. Keep Cooking to a Minimum

Cooking at home adds heat to your air-conditioned interior. This means your air conditioning system will have to kick on to counteract the added heat.

Obviously, if you cook less often at home, you’ll be reducing the heat you add to your home and save money on your AC bill. However, you might end up spending more money on take-out.  A great alternative might be cooking outdoors with a grill or smoker.

29. Have the AC Professionally Serviced

Getting your air conditioning system professionally serviced once per year is the best way to maintain your system. It reduces the need for repairs, frequency of breakdowns and extends the lifespan of your air conditioner.

You can schedule routine maintenance with your local HVAC contractor. An HVAC technician will inspect and tune-up your air conditioner’s indoor and outdoor unit.

Need a HVAC Expert?

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Keep Your HVAC System Efficient

Running your air conditioner in the summer uses a lot of energy and puts strain on it. Fortunately, with our detailed tips above, you can optimize the performance of your air conditioner.

Putting these air conditioning tips into practice will reduce the amount of energy your air conditioner uses, lowering your energy bills. Plus, since your AC unit will be running less often and has less strain, you reduce the likelihood of breakdowns and costly repairs.

Do you have any questions relating to this article? Email us at [email protected] or call us on +1 (310) 961-4908

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Jonathon is a mechanical engineer with over ten years of experience in the HVAC industry. He has hands-on experience with all types of HVAC systems.

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