As the summer season drags on, you might find that your window air conditioners are losing some of their cooling power. It could be that you installed them improperly, the effects of which are now being felt. Or a few key maintenance checks might be in order.

Step 1: Check the Placement
For starters, it’s best to avoid placing a room air conditioner in a window that’s pounded by sun, since direct sun will force it to work harder. North-facing windows receive the least sunlight, or look for a window on another wall that’s shaded by trees, an awning, or another source of coverage. Closing curtains and blinds is another way to reduce solar heat gain.

Moving indoors, it’s also important to keep heat-generating objects, such as a TV or floor lamp, away from the air conditioner. That’s because the unit’s thermostat can sense their heat, causing the unit to run longer than necessary.

Finally, our tests have found that some room units do a better job blowing air either to the right or to the left. This won’t be a factor if the air conditioner is installed in a window located in the center of the room. But if the windows are all near a wall, choose one that will allow the air to blow toward the middle of the room, rather than into the wall. Some models are omnidirectional.

Step 2: Maintain the Machine
All room air conditioners have a filter behind the front grille that can get clogged with dirt and dust, which reduces airflow through the unit, diminishing its efficiency and ability to clean the air. A few times a season, pop off the grille and take out the filter. Remove debris with a vacuum then wash the filter in warm, soapy water. Let the filter dry before reinstalling it. If the filter is badly worn, it’s time for a new one.

You should also inspect the window seals around your unit to make sure hot air isn’t getting into the room or cold air escaping. If leaks are present, reseal around your unit with weatherstripping.

Step 3: Program It Properly
We’re seeing more programmable window air conditioners and even connected units that can be controlled from your smartphone. Whether you have one of these high-tech air conditioners or the manually operated kind, give some thought to the temperature setting.

If that’s too hot to handle, see if you can at least tolerate slightly warmer temperatures, since you stand to save 3 percent on your air conditioning costs for every degree you raise the temperature.