Smarter: Why Your Air Conditioner Isn’t Cooling Enough

person using thermostat Photo: Getty Images

The heat this summer has been brutal, and so this week I’m examining the reasons your AC might not be running as efficiently as it can. Other topics covered in this issue: a cleaning hack that made one of our writers sick, and does permethrin-treated clothing prevent tick bites?

Also, if you’re an EV owner, I want to hear from you! Let me know about the things you wished you had known before purchasing your EV in this very short questionnaire.


‘You’re Hot, Then You’re Cold’

A few days ago, I suggested to my boyfriend that given how hot our apartment was, wouldn’t it be great if we could sleep on the rooftop and enjoy the breeze?

He was not as starry-eyed about the proposal. What about mosquitoes? Or safety concerns? And surely I was joking, right?

Yeah, that was a joke, I said, not telling him that he was living with a person who had entertained similar ideas about sleeping on a fire escape and who once dangled her arms outside of an open window at night while she slept just so she could be a little bit cooler.

As much as I would like my rooftop fantasy to be true, right now I’m making do with the heat the same way most people probably are, with fans and an AC. I’m also doing everything I can to make sure I’m optimizing my air conditioning. If you feel like your room isn’t cooling down enough even with a window AC, here are some tips you can try.

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Make sure your AC is in the right place.
Position your window AC units in north-facing and shadier windows, because direct sunlight makes it harder for it to cool a room. Also avoid having your computer, lamps, or any heat-emitting devices block the unit’s airflow.

If you’ve installed foam seals around the AC, check them.
Foam tends to break down over time, including from UV exposure. So it’s helpful to inspect the edges around your window unit to make sure they’re completely sealed and no hot air is infiltrating your room, says Chris Regan, an engineer and CR’s AC tester. You can also use caulk to prevent hot air from coming in.

Clean your filters regularly.
Dirty, clogged air filters will reduce the airflow in your AC units and decrease their efficiency. Vacuum your window unit filters every few weeks and wash them with warm water and soap at least every two months. For a central AC system, have a licensed, certified air conditioner contractor check on it every year.

Avoid portable AC units if you can.
They’re usually noisier, use up more energy, and are far less effective than window ACs at cooling a room. In our tests, it took a portable AC at least 20 minutes and often much longer to lower the temperature in our test chamber from 90° F to 85° F. By contrast, the best window ACs cooled the temperature by 10° F in 15 minutes or less. For highly rated window units, check out our top picks this year. And though we don’t test central air conditioning units, here are the most reliable central air conditioning systems, according to a survey of our members who own them.

And If you want to cut down on energy costs, here are some things you can do: Block the sun from your rooms with blinds, drapes, or shades to minimize the amount of heat you’ll have to get rid of with your AC. Turn on a ceiling fan, which, according to the Department of Energy, can make the temperature feel up to 4° F cooler.

Another important thing to keep in mind is that people tend to operate their AC at too low a temperature, Chris says. Bear in mind that the smaller the difference is between the indoor and outdoor temperatures, the lower your cooling costs will be. If you set the AC to an extremely low temperature when it’s over 95° F outside, the unit might struggle to cool the space to that temperature.

Bonus reading: For a different way to cool and heat your home, here are four reasons you should consider installing a heat pump.


I have a window AC, but what about you? Click below to participate in our poll.


Some of the most excruciating parts of summer are getting into a car that has been baking in the sun for hours. So what are some ways to get your car air conditioning to cool down faster?

🚗 Don’t run your car’s AC before you go. 
The AC works much better when you’re actually driving because the faster the engine turns, the faster the AC compressor runs, which allows the system to cool more effectively.

💨 Open your windows. 
When you start driving, turn on the AC and open all the windows for 10 to 20 seconds to let the hot air out. 

🧊 Set your AC to the lowest temperature.
The air is typically cooled to 38 degrees in a standard AC system. If you set the temperature higher, you’re forcing the system to reheat the cooled air, which is more fuel-consuming. So to make your car air conditioning more efficient, set it to the lowest temperature and adjust your fans if it feels too cold.

Read more of our tips on how to cool your car most effectively while burning less fuel.


Which type of washing machine uses less water, a front-load washer (one that opens from the front) or a top-loader?

(The answer’s at the end.)


Why this Pine-Sol cleaning hack is a baaaad idea.

@consumerreports You might have seen folks using #pinesol to clean upholstered furniture, but we explain why this #cleaninghack may be unsafe. #cleantok #safetyfirst ♬ original sound - Consumer Reports

Among the many cleaning hacks CR writer Perry Santanachote has tried, some are actually helpful and don’t, you know, make her sick, like using a dishwashing wand to clean the shower.


Is permethrin-treated clothing good at warding off ticks? Yes, but it’s not without health risks.


🌶️ What Is Chili Crisp and Why Should You Make It at Home?

Um, because it’s absolutely delicious?

💕 Should You Buy Your Vacation or Honeymoon From BJ’s, Costco, or Sam’s Club?

I need to buy some hot dogs, toilet paper, and a room with an ocean view.

🍹 6 No-Alcohol Cocktails That Fight Inflammation

And all of them are under 100 calories.

🍳 The Surprising Things I Learned When I Ditched My Gas Stove for an Induction Range

Is it worth it to switch?


Well, that’s one sharp chef’s knife. 

@consumerreports Do you know what to look for when shopping for a new chef’s knife? See ratings and reviews at 🔪 #cheftok #knives #kitchenessentials #kitchenskills ♬ original sound - Consumer Reports


The answer is a front-load washer. It uses, on average, around 10 gallons of water per load, less than high-efficiency top-loaders (13 gallons per load) and much less than top-load agitators (20 gallons per load). 

Front-load washers have some other clear advantages going on for them: They’re often gentler on fabrics and quieter than top-load washers. On the other hand, they’re more prone to getting mold and mildew. But if you’re torn between choosing a front-loader vs. a top-loader for cleaning efficiency, here’s our verdict.

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"Summer is my frenemy."

Headshot of CR Author Pang-Chieh (BJ) Ho

Pang-Chieh Ho

I'm a newsletter writer who likes looking into the different ways we can live smarter. The topics I cover typically explore unanswered questions we have about the products we use every day and bridge the gaps between what owners' manuals advise and what we actually do. In my spare time, I like to take photos, critique movies out loud while I watch (at home!), and take care of my ever-increasing plant "children."