14 Free Ways to Make Your AC Energy Efficient

air conditioning unit on outdoor wall
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Your air conditioner keeps your space cool, but the convenience comes at a cost. AC units of all types are energy consumptive, which is hard on the planet and your bank statement.

Rather than swallow the rising cost of cooling your home, keep them in check with some free ways to make your AC more energy efficient.

How to Know If Your System Is Dropping in Efficiency

The first way to tell if your AC is running efficiently is if your bill jumps up but your usage doesn’t. It can be difficult to measure since temperatures fluctuate, but if you see a notable increase, take it as a warning.

If your system is constantly kicking on and off, you may also have an issue. This can be caused by many factors, but the result is confusion for your system, causing it to cycle through unnecessarily.

If you see a visual issue with your air conditioning unit, such as ice formation, condensation, or a dirty filter, or hear unusual sounds, you can wager efficiency is less than optimal.

1. Understand Passive Cooling

exterior solar shading above windows

Embracing techniques for keeping your home cool without using AC is the premier way to keep your AC from working harder than it needs to.

The cooler you can keep your home by other means, the less you’ll need to rely on mechanical cooling systems. Basically passive cooling is any practice that cools the space without consuming energy. In other words, open a window, block incoming sunlight, and arrange interior layout to maximize airflow.

2. Time It Right

One key component of natural ventilation is tapping into cooler air when it’s available. Depending on where you live, the coolest air in any 24-hour period comes after the sun goes down.

Open all the windows overnight, if possible. If there are safety or other concerns, open all screened doors and windows as soon as the temperature outside is lower than the temperature inside.

Leave them open until you go to bed and open them again as early as possible in the morning.

3. Use Airflow to Your Advantage

open windows with nature outside

Remember the basic law of thermodynamics is that heat rises. It’s important in helping to clear the warm air out of your home and there are several ways to implement this law into your natural ventilation.

First, drive air from the lower levels to the upper levels through fans and/or open windows. This allows cooler air to replace warmer air on upper levels.

It’s called the chimney effect and it’s driven by convection. When cool air enters the home on the lower level and mingles with the heat in the space, the combined mass rises to the upper level where it escapes out the open windows.

The lower space then refills with air from the open window, creating a vacuum effect that continuously pulls air through the space. The chimney effect is particularly effective in homes with cathedral ceilings or open skylight windows.

4. Let the Fans Do the Work

smiling woman in front of fan

While fans may not be completely free to operate, they are significantly less expensive to run than air conditioning units. Rely on fans to circulate air and drive warmer air out of the room.

On lower levels, place fans in front of open windows and doors when the air is cool. This will drive cooler air into the space. Upstairs, aim fans towards the openings to drive warm out.

If you live in a single level home, place fans away from one opening and facing another opening to guide air through the rooms.

You can also rely on ceiling fans to help with temperature control. Most ceiling fans have a setting that allows you to reverse the direction of the blades.

Rotating one way, the blades push warmer air down into the room (during winter). Rotating the other direction, the blades pull warm air up towards the ceiling, keeping the living space cooler.

5. Cue the Cross Breeze

breeze in bedroom coming through curtains

Creating a cross-breeze is one of the most effective ways to cool a home. Many resorts and vacation homes in tropical areas rely on this technique instead of installing AC for a good reason—it works.

The key to effective breeze cooling is figuring out which direction the wind blows. In some areas, it’s fairly consistent, commonly coming from the same direction during the same times each day (most often in the afternoon).

Open up windows during that “window” of breeze to encourage the flow through your home.

As mentioned, take advantage of cooler nighttime and early morning temperatures. Leave screened windows open to allow the cool air in. Then trap it inside by shutting windows on each side of the house as the sun hits it, i.e. the east side in the morning and the west side in the afternoon.

6. Effectively Manage Heat from Activities

The way you go about activities around and inside the home has a significant impact on the workload of your AC. Avoid heating the space up during the day when temperatures are warmest.

For example, close whatever window coverings you have on the inside or the outside of your windows. A dark space will stay cooler. If you have blackout curtains, you’ll notice the best results.

Even during the sultry days of summer, you need to eat and do laundry, but appliances in the home generate a lot of heat and compromise your success in the battle against a hot house. Plan ahead to avoid turning on appliances as much as possible.

Dust off that crockpot book and cook dinner without turning on the stove. Also enjoy some summer grilling that takes the hot cooking outdoors. Better yet, on very hot days, go with a cold sandwich or salad and avoid cooking altogether.

Avoid running the dishwasher during the day and turn off the heat dry setting.

In the bathroom, take cool showers, open the window, turn on the fan, and skip the hair dryer. Showering at night is also helpful.

Also save laundry for the evening hours and hang clothes instead of running the clothes dryer. Remember, all the heat you create will make your AC work harder.

7. Turn up the Thermostat

If you have central air conditioning, put some thought into using it. Every degree you adjust is a decision between saving and spending—conserving or consuming.

Turn it on if you need to, but consider redefining your definition of comfort by a few degrees rather than being wasteful.

If the opportunity arises, swap out your thermostat for a programmable model. You can even get smart models now you can control from your phone.

These devices provide better control when it comes to responsible AC usage. Turn the system off or change the settings remotely if you’re away from home.

Similarly, when you are home, program the system to provide a comfortable atmosphere when the family is using the space, but keep it from kicking on when everyone is gone, and at night when natural breezes do the job.

8. Maintain Your AC Unit

hands cleaning AC filter

Like all appliances, your AC unit will work most effectively when it’s kept in well-maintained condition. Clean your coils at least once each year. Also clear the drain line on a central AC system.

Head outside and clear away debris from your AC unit a few times each year too. If your system suffers from build-up and lack of cleaning, it will cause it to overwork, which decreases efficiency and costs you money.

Although not free, replace your furnace filter every one to three months. This is the best way to keep your AC and your heating at tip-top performance. If you have a portable or window unit, it will likely have a washable filter to clean several times each season.

9. Keep Vents Clear

Air circulation is key to an efficient AC system. Keep your units from overworking by ensuring clear airflow throughout the space. For example, if you rearrange the furniture, plan placement so the vents aren’t restricted.

10. Check Your Bulbs

Light in any form creates heat. When it’s time to replace bulbs, swap out the incandescent bulbs for cooler, and more energy efficient, models.

Always turn out lights when you’re not using them to keep the heat down and the energy savings up. Also make sure motion-sensored and smart-controlled lights are properly set so they’re not illuminating more than necessary.

Finally, keep lamps away from the thermostat, which could cause a higher temperature reading and initiate air conditioning to kick on.

11. Clean House

As mentioned, a clean air conditioning system will work most effectively. Keep the system from working to filter out dirt and grime by keeping a clean house. Dust, sweep, and vacuum often.

Also remove your vents and vacuum them out at least once a year. Change your vacuum bag or empty your canister before it’s full for maximum efficiency. Also clean your vacuum filters regularly.

12. Shade Your Condenser

shaded AC condenser outside

The large outdoor unit of your AC system is the condenser. It may be located on the roof or around the foundation of the house. This large unit is the workhorse of your AC system. You can help it work more effectively by providing shade.

Alongside the house, you can place plants that will shade the unit. Just be sure they don’t drop leaves or other debris inside the condenser.

You can also place a shade sail or umbrella over the unit, whether it’s on the ground or on the roof. The key is to make sure you don’t restrict airflow, so keep coverings away from the sides and top of the unit.

13. Insulate Against Air Loss

With all of this talk about the importance of air flow it seems counterintuitive to mention insulation. However, keeping hot air from entering your space keeps you from having to then cool it.

Similarly, keeping the air you’ve paid to cool from escaping means your AC unit doesn’t have to work so hard. Insulation stifles airflow keeping warm air out and cool air in.

Just like with cold air during the winter, evaluate any place air flows from indoors to outdoors. Close the damper in your fireplace.

Feel around your doors and windows for airflow and install weatherstripping as needed.

Grab a package of insulation foam for your light switches and outlets.

Use the insulation that came with your window air conditioner or portable air conditioner.

In addition to sealing all the holes, be ultra conscious of opening and closing doors. Even a few minutes with an open door can flood a room with warm air on a hot day.

An open door also allows cold air to escape, to which your air conditioner will respond by kicking on to once again cool the air.

14. Build a Homemade Cooler AC

There’s a quick and simple way to cool a small space, with a cooler, ice, and a small fan. Really, this technique mirrors what an air conditioner does by forcing air through material that cools it.

Styrofoam coolers work great for this project, but you can cut into a regular cooler if you want too. To start, cut a hole in the top of the cooler that is about the size of the fan’s faceplate. Place the fan face down into the hole. You can use a corded fan or a battery-powered option.

On the opposite end of the cooler, cut out a hole or two, the size of whatever PVC pipe or similar ‘exhaust’ material you have laying around. Insert the piping into the holes. These are where the cool air will be released. Fill your cooler with ice and chill out.

A Note About Other Types of AC Units

If you have a window unit or a portable air conditioner, the same guidelines apply. For mild climates, resist putting window air conditioners in place until the heat really sets in, and remove them as soon as nighttime temps begin to drop. That way you can use the window for free and natural ventilation rather than expensive AC.

For other ways to save money and the resources of the planet, check out What is Passive Solar Heating? and The Efficiency of Ancient Passive Heating and Cooling Techniques.