
AC Unit Not Blowing Cold Air? It's Time to Change Your Filter
Every year when I pull my air conditioner out of storage and reinstall it, I'm worried about whether my window unit managed to survive the colder months. This year when I turned it on, I was worried when instead of a cool breeze, my AC unit was blowing tepid air. I was braced for the worst and did the math on how much a new one would cost, but thankfully it wound up being a simple fix. I just needed a new air filter.
Once I pulled it out and saw the mess, it made sense. A dirty filter slows everything down and forces the unit to work harder, sometimes to the point where it stops cooling altogether. The fix? A quick clean or a swap for a new one, depending on your setup.
Now I make a habit of checking the filter regularly. It takes just a few minutes, but it keeps the air cold, clean and flowing. That's a lifesaver during these brutal summer months.
Below we'll outline when to change your AC filter and how to swap it the right way to guarantee your AC unit runs properly and efficiently. For more, explore these six ways to save on air conditioning this summer and effective ways to lower your AC bills when on vacation.
Read more: How to Clean Your Air Conditioner So It Runs Like New
Here's how to tell if your AC filter needs changing
The only real way to know it's time to replace your AC filter is by checking on it every so often. To do so, pop your AC filter out and hold it up to the light. If you can't see through the filter, then it's time for a new one. Below, find step-by-step instructions on how to change out your filter.
If your air filter looks like the filter on the left, then it's time to replace it.How to change an AC home air filter
First things first: You need to locate it. It could be several places: in the air handler cabinet, return air duct or in a window AC unit, etc.
Next, make sure you get the right filter size -- the dimensions are usually printed on the side of the filter – so you can make sure you're buying or ordering the right size replacement.
Now, it's time to actually change the filter:
Turn the power off . This will ensure that you don't touch live voltage or that debris be sucked into the unit. So, be sure to turn off power at the unit and also at the circuit breaker.
. This will ensure that you don't touch live voltage or that debris be sucked into the unit. So, be sure to turn off power at the unit and also at the circuit breaker. Remove the old filter. Simply slide it out of the slot that holds it in place.
Simply slide it out of the slot that holds it in place. Take note of its condition . Can you see through it when it's held up to the light? If not, definitely time to replace it.
. Can you see through it when it's held up to the light? If not, definitely time to replace it. Insert the new filter. To make sure you get it in the right way, make sure the arrow icon on the filter's frame points away from the return air duct and toward the air handler mechanism.
Buy the right size filter by checking the dimensions printed on the old filter's frame.
mphillips007/Getty Images
How often does an AC filter need to be changed?
Do you know off the top of your head the last time you changed your filter? If you can't remember, it has no doubt been too long.
Many HVAC filters actually say on the packaging that a monthly check-in is ideal to keep dust and allergens to a minimum. For the most part, experts agree your filter will probably need to be replaced every three months or so, but monthly assessments can guarantee you don't leave a worn-out filter in your unit for too long past its effectiveness.
Other factors that change the lifespan of your AC filter
Depending on a number of factors, such as your surroundings, the season and the inhabitants of your home, you may want to replace your air conditioning filter more or less often than once a month.
Air filter type
Some air conditioning filters are made to last longer than others. But luckily, you don't have to do a ton of research or be an AC expert to know which brand is best. Just look at the packaging.
All AC filters have a Minimum Efficiency Reporting Value (MERV) rating. The higher the MERV number, the better quality the filter is, meaning it can hold contaminants or debris more efficiently and therefore lasts longer.
The only downside to picking a filter with a high MERV rating is that it can slow down the airflow in your AC unit. The best filter options will have a balance between good quality and good airflow, which is typically a filter with a MERV rating between 6 and 8. If you have a high-efficiency AC unit, you may be able to get away with a higher MERV rating, but check the owner's manual just in case.
Geography
Geography and seasonality can also affect how often your filter will need to be replaced. Living in a dusty or more polluted environment calls for a new air filter at least once every three months.
For example, in desert climates, your AC is filtering out all that desert dust (in addition to 90-plus degree temperatures) to keep the air in your home pleasant to breathe. Your AC is likely working overtime, which means it'll need extra maintenance.
Pets
What sort of creatures inhabit your household can also determine how often you'll need to replace the filter. If you're like me and have two long-haired pets living with you, checking your filter every three weeks is a good rule of thumb to prevent build-up.
Usage
If you live in a temperate climate and rarely turn your AC unit on, you can probably wait up to six months to change the filter. A simple way to remember is to switch the filter out once in the spring and again in the fall.
Watch this: Beat the summer heat with this DIY air conditioner
02:39
An added incentive to change your filter
Not only can regularly changing your AC filter help improve your home's air quality and conditions, it can save you money over time. Replacing a dirty, clogged filter with a new, clean one can lower your air conditioner's energy consumption by 5 to 15 percent, according to the US Department of Energy. And less energy consumed by your AC equals lower utility bills, which is a huge perk in the heat of summer when electricity costs spike for much of the US.
For more, you can also check out this home upgrade that can save you money on AC costs and this comparison between window AC units and portable AC units.

Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles


Washington Post
40 minutes ago
- Washington Post
Protesters block highway in Los Angeles
We and our third-party partners process personal data including through the use of cookies, pixels, and other tracking technologies to provide, analyze, and improve our services; personalize your experience (including content); and personalize ads on and off the services. Learn more and manage your preferences at our Privacy Policy


CBS News
an hour ago
- CBS News
Denver voted best tap water in the U.S. and Canada but conference judges award Virginia community
Denver voted best tap water in U.S. but Virginia county wins over judges Denver voted best tap water in U.S. but Virginia county wins over judges Denver voted best tap water in U.S. but Virginia county wins over judges Attendees of a tap water conference voted Denver has the best tap water in the U.S. and Canada, but judges from the organization disagreed. The American Water Works Association just awarded Henrico, Virginia, the accolade at the annual AWWA Annual Conference and Exposition in Denver. The region near Richmond faced off against cities and communities across the country, including Denver, but ultimately beat Denver, along with other communities' tap water. Three judges tasted samples from 26 water utilities across the U.S. and Canada. Denver scored a first-place spot in the "People's Choice" category -- voted on by all conference attendees -- but failed to place in the top three among the judges in the "Best of the Best" category. "People's Choice": Denver Appleton, Minnesota Bloomington, Minnesota Taylor Wilson, left, of Denver Water, accepts the "People's Choice" award on behalf of the city for best tap water in the U.S. and Canada at the American Water Works Association's 2025 conference in Denver on Tuesday, June 10, 2025. CBS While perhaps a product of the attendees having had a lot of Denver's water throughout the four-day conference, Denver and Colorado rarely rank particularly high in lists of best-tasting or cleanest tap water. U.S. News and World Report recently ranked Colorado as 33rd for drinking water quality among U.S. states and Colorado failed to rank in the top 10 for large metro areas in the U.S. in a recent J.D. Power U.S. Water Utility Residential Customer Satisfaction Study. Denver did, however, rank 9th in its 2025 study in the "West-Large" regional category and in its "West-Midsize" regional category, Colorado Springs Utilities ranked 6th and Aurora Water ranked 10th. American Water Works Association judges taste tap water from utilities around the U.S. and Canada at the organization's 2025 conference in Denver on Tuesday, June 10, 2025. CBS The "Best of the Best" winners at the AWWA conference were: Henrico, Virginia Taylorsville Bennion Improvement District, Utah Ames, Iowa The conference wraps up on Wednesday and includes a number of competitions, including a "meter challenge," pipe tapping competition, and more. The finals for each of those competitions are on Wednesday.
Yahoo
an hour ago
- Yahoo
All 6 killed after plane crashes into ocean near San Diego
The Brief All six people aboard a twin-engine Cessna 414 died after the plane crashed into the ocean near San Diego. The pilot reported trouble maintaining altitude and twice turned toward shore before the crash, according to audio and radar data. The FAA and NTSB are investigating, and the victims have not yet been officially identified. Six people were killed after a plane crashed into the ocean 5 miles off the coast near San Diego, authorities said. What we know The twin-engine Cessna 414 crashed at around 12:30 p.m. Sunday, not long after it took off, the Federal Aviation Administration said. The plane was returning to Phoenix one day after flying out from Arizona, according to the flight tracking website Searchers found a debris field later Sunday about 5 miles off the coast of Point Loma, a San Diego neighborhood that juts into the Pacific, U.S. Coast Guard officials. The water in the search area is about 200 feet (61 meters) deep. The pilot told air traffic controllers that he was struggling to maintain his heading and climb as the plane twice turned towards shore before going back out to sea, according to audio posted by and radar data posted by FlightAware. The controller urged the pilot to climb to 4,000 feet after he reported the plane was only about 1,000 feet in the air. The controller directed the pilot to land at a nearby U.S. naval airport on Coronado Island, but the pilot said he was unable to see the airport. A short time later, the pilot repeatedly signaled the "Mayday" distress call before controllers lost radar contact. What we don't know Although the FAA said all six people on board the plane were killed, authorities haven't identified them. Dig deeper The FAA said the plane is owned by vitamin and nutritional supplement maker Optimal Health Systems. But the company based in Pima, Arizona, said in a statement that it sold the plane to a group of private individuals in 2023, meaning the FAA database could be out of date. However, the company's founder, Doug Grant, said in the statement that, "We personally know several of the passengers onboard and our sincerest condolences are offered to those affected by the tragedy, all of whom are incredible members of our small community." The crash comes weeks after a small Cessna crashed into a San Diego neighborhood in foggy weather and killed six people. What's next The National Transportation Safety Board and FAA confirmed they are investigating the crash. Local perspective A man who was out surfing when the plane crashed told NBC 7 in San Diego that he saw the plane come down at an angle, then climb back into the clouds before diving again and crashing into the water. "The next time he came out of the clouds, he went straight into the water. But after I saw this splash, about six seconds later, it was dead silent. I knew that they went in the water, nose first, at a high speed," Tyson Wislofsky said. The Source The Associated Press contributed to this report. The information in this story comes from official statements by the U.S. Coast Guard and the Federal Aviation Administration (FAA). This story was reported from Los Angeles.