condition 1 : www.ahs.com/home-matters/repair-maintenance/how-to-install-a-window-air-conditioner/ How to Install a Window Air Conditioner | Home Matters | AHS

Your browser is out of date.

For the correct work of a site, install the new version.

ALERT If you received an email from American Home Shield stating that our contractor has been unable to reach you -- and you do NOT have an open service request -- please disregard it. We apologize for the confusion. This message was sent in error. Thank you for your understanding.
Repair & Maintenance

How to Install a Window Air Conditioner

If you think installing a small window air conditioning unit is a big job, you might be surprised. With some information, planning and the right tools, you can complete this do-it-yourself project and keep your cool at the same time.  Here’s what you’ll need to do:

Small ac unit

Gather Tools and Materials 

  • Tape Measure 
  • Drill 
  • Screwdriver 
  • Safety Goggles 
  • Torpedo Level 

In addition to your air conditioning unit, you’ll also need some insulating foam panels or strips to fill in any gaps between the unit and the window frame.  Heavy work gloves may also help protect your hands and help you grip the unit as you lift.  It’s also helpful to have an extra pair of hands around to assist with lifting and positioning the unit, so ask a friend or family member to be present when it's time to install a window air conditioner.

Know Before You Purchase

Before you purchase and install a window ac unit, you’re going to have to do some homework and research for window installation.  Choose the window where you will place your unit, preferably near a three-pronged electrical outlet. If you don’t have such an outlet within easy reach of the window, you’ll need to purchase an extension cord that is specifically labeled for air conditioners. 

Choose the right window

Make sure that the air conditioner you select is designed for the type of window that will house it. Is the window double-hung, casement, or a slider?  Many units require a sash or double-hung window that can be raised and lowered, so if you have another kind of window, you’ll need to shop for a unit that is compatible.  It’s also important to accurately measure the width and height of the inside of the window frame to make sure the window unit will fit properly.

Okay, one last thing that you'll need to know is your room size to make sure the air conditioner can adequately cool the area.  The cooling capacity of air conditioners is rated in British Thermal Units, or BTUs.  Ask your local home store or air conditioner retailer to help you calculate how many BTUs you need for cooling your specific area.  You may need to adjust your cooling requirements if your room has high ceilings or if the window is in a sunny spot. 

RelatedLet the Fresh Air In - Your Window Guide for Spring 

Energy Efficiency Rating of Window Air Conditioning Units 

Now that you have an idea of what all you'll need, it's important that you also consider the Energy Efficiency Rating, or EER, of the unit that you purchase. The EER measures how well the air conditioner converts cooling energy, and a higher rating means more energy efficiency.  Units with the ENERGY STAR rating use 10 percent less energy and cost less per year to run.  You’ll also want to look for other cooling features that can help increase energy efficiency and enhance your comfort, such as variable fan speeds, digital temperature control, energy-saving settings, timers, learning & programmable thermostats. Next, it's time to get the ball rolling with installation! 

RelatedSteps to install a learning thermostat and save money on energy 

How to Install Window Air Conditioning Unit

Step 1:  Prepare Your Window 

For installing a window air conditioning unit, take the time to inspect the window and make sure the frame is in good condition and doesn’t have any obstructions. If there’s a storm window, you’ll have to remove it or affix a spacer block to the windowsill to raise the air conditioner away from the storm window frame.  After you’ve prepared the window, read the manufacturer’s installation instructions carefully before you start the mounting process.  Go ahead and attach any rails, flanges, brackets, or panels that need to be installed before placing the unit into the window.

Step 2:  Mount The Air Conditioner On The Window

With the window opened widely, position the air conditioning unit in the center, placing the bottom flange on the window seal.  Close the window onto the unit.  Before going any further, it’s important to make sure that the unit will be level so that it will operate properly.  Check the air conditioner’s position with a torpedo level and adjust accordingly before anchoring it into place.

Step 3:  Secure Air Conditioner In Place 

Affix any brackets that came with the assembly by drilling pilot holes and tightening the screws with a screwdriver.  Open the side panels and insert screws or clips to immobilize them, and add foam strips or panels around all sides as needed to seal off the unit as completely as possible.  In addition to preventing insects and moisture from entering the room, a good air conditioning seal prevents cool air from escaping the room.

Step 4: Test Your AC Unit

After you’ve made sure that all the parts of the air conditioning unit are installed correctly, it’s time to plug in the air conditioner and turn it on.  Avoid placing other electrical appliances, like lamps or televisions, near the air conditioner’s thermostat, as the heat from these appliances can signal the air conditioner to cool longer.  For the greatest energy efficiency (and lower utility bills), choose the highest comfortable thermostat setting, and avoid running the unit when it’s not needed. So there you have it. You've learned how to install your window air conditioner so now, you can beat the heat and stay cool.

Don't forget that after you've installed your small window ac unit you'll need protection for everyday wear and tear. Don't let your new appliance go unprotected. Protect your budget from unexpected appliance breakages and repairs with a Home Warranty Plan from American Home Shield®.


Affordable plans

Affordable plans for
inevitable breakdowns.

Protect your home's systems and appliances from unexpected breakdowns with an American Home Shield® Home Warranty.

Get a Quote
It only takes a few seconds.