How to make a Window AC more efficient (9 Methods)

Window ACs are power-hungry! Even though they are one of the most-efficient AC types, their running cost adds up over time.

In this article, I’m going to explain 3 essential things you should do to make your window AC more efficient.

Quick Answer: You can make your window AC more efficient by insulating windows and gaps below your door. Also, clean the evaporator coil and air filter. To avoid efficiency-decreasing dirt accumulation, clean your window AC’s internals yearly. Additionally, use high-quality extension cords (instead of cheap ones) and run your AC on a moderate cooling setting. 

The efficiency of a window AC defines how well it utilizes electric power to produce cold air.

In other words, if your window AC is not cooling efficiently, your unit consumes more power.

Let’s have a look at some of the tips you can use to make a window AC more efficient.

Improve window AC efficiency through insulation

Your window AC’s efficiency can be increased by changing a few things in your room, and you won’t even need to touch your unit. 

All you have to do is to insulate your room correctly, and I’m going to tell you how you can do this easily. 

Keep your doors closed

If you are using a window AC in your room, ensure every door of your space is closed before turning it on. 

This will allow you to lock all the cooling inside your room and prevent heat from entering it.

Also, if the room doors are open, window AC tries to cool the air outside the room as well and consumes energy accordingly. 

If you close your room doors, your window AC will not have to consume more power to cool down the area outside the room. 

Also, your room will remain cold even after turning off your window AC unit. 

Insulate the Window AC setup

As window ACs are installed on the windows and walls, there is a high possibility of gaps in the Window AC setup. 

These gaps can ruin your room’s cooling, allowing the outer heat to enter and the inner cool to leave.

That is why it is important to properly seal the gaps and insulate the window AC setup to save cooling and bills. 

If your unit is set up on a window, make sure to seal the gaps between the frames of the lower and upper sash. 

There should be no gaps or cracks around the panels (side panels).

You can also insulate the window AC setup by:

  • Using thermal curtains
  • Using Bubble wrap to seal the opening in your window
  • Doing removable magnetic insulation
  • Using fiberglass
  • Spray foam insulation
  • Using foam tape (to air-seal the window)
foam tape

Block the gap below the door 

I’ve already discussed how hot air can ruin your room’s cooling if it makes its way into your room. Therefore, you should block the gap below the door to prevent this from happening. 

Any heavy or thick fabric can block the gap below your door. It may, however, cause problems when opening and closing the door. 

I’d recommend using an under-door draft stopper (usually made of rubber) to block the below-door area.

The best thing about the draft stopper is that you won’t need to remove it repeatedly as you open or close the door.

For more window AC insulation tips, check out: How to insulate a Window AC (for efficiency)

Improve window AC efficiency through maintenance

Maintenance of a window air conditioner is essential as it helps keep it fresh and increases its life and efficiency. 

While maintaining your window air conditioner, you must clean its filter and coil and schedule maintenance once a year. 

So, let’s start with the maintenance of your window AC unit. 

Clean the Coils 

The function of the coils is to move the hot air out of the space and let the cool air in through the window AC unit. 

This process attracts dirt and dust. If there is dirt, the unit will have to work more, reducing the AC’s lifespan and increasing energy bills. 

To allow it to work efficiently, clean the coils using a brush and a cloth (you can also use a handheld vacuum cleaner).

How to properly clean the coil?

  • The first thing you should do is turn off the window air conditioner.
  • Remove the front panel and clean the unit’s fins using a soft brush or a cloth. 
  • Clean the unit’s coil using a coil cleaner ( it can be foam or water solution). 

You can also use soapy water instead of the coil cleaner, but make sure to dry out the parts before you turn on the unit.

Clean the filter

The filter is like a superhero of a window AC, as it stops dust particles from entering the window AC unit and keeps it clean. 

These dust particles accumulate on the filter, making it clogged after some time (If not cleaned frequently) 

When the filter is clogged, your window AC consumes more power to get the air from the filter. 

Cleaning the filters is necessary because it keeps the air quality fresh and helps make the window AC work more efficiently. 

Even though it is easy to clean the filters, we tend to forget them more easily. You should clean the filter dust buildup at least every week, and if you are not using it regularly, then at least once or twice a month. 

Also, you can use soapy water and rinse it with water. 

How to clean your window AC filter? 

First, check the user manual of your window AC unit and remove the front panel accordingly. You will see the filter; press it a little until it comes out.

I recommend dry-brushing your AC filter, since water enhances mold and bacteria growth.

At least in my personal experience, air filters tend to stink after rinsing them with water. So, I rather dry brush all the dust off.

The filter should not be damaged as it will let the dust go through, damaging the unit. Replace it if it is damaged. 

If you want to avoid any dust inside the unit during off-seasons, you can cover it using the AC covers. It will be helpful to prevent debris and dust from building up in the unit. 

Covers avoid not only dust but also rust.

Perform a yearly AC maintenance

If you are using your window AC without servicing it for a long time, then it will likely consume more energy. 

Not only will it consume more energy, but it will also provide poor cooling.   

When a window AC keeps running without thorough maintenance, the dust particles will settle down in your unit. 

As a result, the coil and filter will get choked, and your the AC unit’s internal heat transfers (to remove the heat from your room) won’t work efficiently.

And you end up with repair costs and energy costs. 

So, make sure to schedule complete maintenance of your window AC unit once a year (or at least every two years).

Reduce your window AC’s power consumption

You can make your window AC more efficient by decreasing the power consumption of your unit. 

The power consumption of window AC is inversely proportional to its efficiency. 

Power consumption = BTU (Cooling Capacity) / Efficiency 

If we somehow manage to reduce the power consumption of our window AC, the efficiency will increase. 

Below are some of the methods you can use to reduce the power consumption of your window AC unit. 

Use a heavy-duty extension cord

If you use an extension cord to supply the power to your window AC unit, ensure it’s not worn out and is low-quality. 

If you use a low-quality and worn-out extension cord, it consumes more power to power your window AC unit. 

Also, it can get overheated after some time, causing damage to your unit or any electrical hazard. 

So, make sure to get an extension cord that can withstand more current than your window AC draws. 

It will help you save bills and get the best performance out of your window AC. 

For example, if your window AC draws 19A current, your extension cord must be a heavy-duty extension that can withstand 20A current. 

Also, do not use long extensions and power cords because they increase total power consumption.

heavy duty extension cord

Run your AC at moderate cooling settings

The best and easiest thing you can do to reduce power consumption is to set your AC settings to moderate cooling. 

The logic is simple if you set your window AC to its extreme settings, it will keep running to decrease the room’s temperature. (According to the cooling settings) 

As a result, your power consumption will increase, and efficiency will decrease. 

So, Setting your window AC temperature at a moderate temperature is ideal for energy saving and attaining a comfortable temperature.  

What to do if your window AC is still not cooling enough?

Even after trying all these hacks mentioned in this article, you still struggle to improve your AC’s efficiency and reduce energy bills. It’s time to replace your window AC unit.

There could be two main reasons your window AC is still not cooling enough after trying these hacks: 

  • Your window AC is very old. 
  • Your unit has been through several repairs. 

So, if your AC falls on this list, then it’s to replace your unit with a new and more powerful one. 

I will highlight some signs if you’re still unsure whether you should replace your AC. If your AC shows these signs, then you must replace it. 

  • The window air conditioner is older than ten years.
  • The unit is making a lot of grinding or scratching noises. 
  • When turned on: it smells smoky/burning. 
  • It needs a lot of repairs from time to time to function. 

I’ve recommended a few best window AC in a separate article. If you want to buy a new one, you should check this one: Best Air Conditioner for Small rooms


If the efficiency of a window AC is less, it consumes more power to perform well. The higher consumption of power increases energy bills. 

With a few simple hacks, you can improve the efficiency of your window AC and cut down on your energy bills.

Insulate your room and window AC setup properly. Clean the coils and filters of your unit frequently. Also, Keep your settings at moderate cooling. 

If these hacks don’t work for you, your AC may need a repair, or it’s time to replace your window AC for good.