Heading into summer in the Pacific Northwest means preparing for more than higher temperatures. It means getting ready for inconsistent weather patterns, smoke season, and possible heat domes.
It’s good to prepare for generally worse air quality, too. Indoor air quality can deteriorate in the summer due to pollution, fires, and extreme heat that can prolong allergy season and supercharge mold growth. This is more than uncomfortable. It can make you and yours less safe.
To help you get ready, we compiled a list of everything you can do to optimize your home and your HVAC system before summer hits.
Inside Your Home
Common Sense Stuff
Before you think about your HVAC equipment, there are things you can prepare to do to that will keep your home cooler.
Fans. Make sure you have fans that function. Turning on a ceiling or freestanding fan won’t actually cool the air but it can make you feel up to four degrees cooler than you would otherwise (due to the magic of the wind chill factor.)
Close the shades. Remember to close your shades or curtains during the hottest parts of the day to keep the sun from heating up your space.
Seal it up. Seal windows and doors so you can keep hot air outside and cool air inside. This will also make your house more efficient (which can curb your electricity bill) and keep mold-producing moisture away.
Keep humidity in check. The humidity level in your home is a major factor in maintaining a comfortable indoor temperature. Aim for about 60 percent humidity.
Keep the oven off. Use heat-generating appliances, like dryers and ovens, late in the day or early in the morning.
Bathe in cool water. Taking a cool shower before bed can help keep your body temperature down.
Monitor the air quality. Check to see what the air quality in your area is before opening doors or windows for “fresh air.” If particulates are high, it’s better to keep doors and windows closed and let your air filters do their work. In fact, indoor spaces stay cooler in general if you keep doors and windows closed.
Check Your Thermostat
Before hot temperatures descend, check out your thermostat to make sure it’s working.
Check the battery. First things first. Test the batteries in your thermostat to make sure they’re still good, especially if you have an older thermostat. Replace them if they’re not.
Run your cooling system. Run the cooling system before it gets super hot, just to make sure it’s working. If it’s not cooling your space, call your HVAC service company to get a maintenance check.
Check your programming. Do you remember how to set your thermostat? Remind yourself now: find last summer’s program or set a program for the summer months.
Set a reasonable temperature. Your cooling system is designed to keep your home in a comfortable range, not to freeze you out.
Trane, a manufacturer of heating and cooling systems, says, “When the outside temperature is in the high 90s or more than 100 degrees, your cooling system has to work hard. The closer the indoor temperature is to the outdoor temperature, the more efficiently the unit will work. Avoid turning the thermostat down drastically when you come home. Doing so won’t cool your house any faster and can stress your system.”
Upgrade and save. If you’re in the market for a new thermostat, consider a smart model that can give you full remote access. This will help you set temperatures from afar so your house is cool when you return.
Check Your Air Filter
Your air filters do the heavy lifting all summer by screening out particulates, spores, and other irritants. The dirtier your filters are, the harder your system has to work. Making sure they’re clean or new—at the beginning of summer and throughout this hottest season—will help your equipment do its job more efficiently and effectively.
Replace your filter. How often you replace your filter depends on the type of filter you have. In general, one-inch filters need to be replaced every three months and four-inch filters at least twice a year. If you have pets or people in your home with allergies, you’ll need to replace them more often. Ditto for summertime. You may need to replace your filter every month.
Clean your permanent filter. If you have a washable metal filter, begin the season by getting it clean. To clean it, follow these instructions.
Keep checking your filter. Experts recommend checking your filter every 30-60 days during the peak season to make sure you have the cleanest air possible.
Check Your Air Ducts
To get your house ready for the heat, consider having your ducts cleaned. Cleaning your ducts can:
Greatly reduce allergens, like pollen and dust, that have built up on interior duct surfaces. This can help boost air quality.
Make your system work better. Clean ducts can improve airflow in your home and help your system work more efficiently.
Eliminate odors. If your ducts are full of pet fur and dander, mold spores, or other foreign materials, your house might smell musty. Cleaning them can help get rid of dank, dusky scents.
Outside Your Home
Clear and Prune
It’s important to remove debris from around your outdoor cooling unit. A buildup of grass, leaves, dirt, and the like can clog lines and damage coils, leading to expensive repairs. It can also cause extra dust to get caught in your system, which can make allergies or irritated lungs worse.
Make sure you also prune back any vegetation so there’s a clearance of at least two feet around your cooling unit. This helps with air circulation, which is crucial for your system to run the way it should.
Schedule a Maintenance Check
Finally, schedule with your professional HVAC maintenance crew. When they service your system, they will:
- Check your condensate line
- Clear any clogged lines
- Clean your condenser coil
- Fix airflow leaks
- Inspect your fan and blower
- Check the function of your capacitor
- Make sure your system is draining properly
- Check and correct your refrigerant levels
Once your system is serviced and you’ve changed or cleaned your filter, checked your thermometer, and cleared debris from around your outdoor unit, you’ll be ready for another hot summer.
Sources
4 Ways Extreme Heat Impacts Indoor Air Quality, filtrete.com (accessed April 28, 2026)
Hot Weather Home Maintenance: AC Care & Summer Prep Tips, Dave Musial, fourseasonsheatingcooling.com, June 2, 2025 (accessed April 28, 2026)
Improving Indoor Air Quality, epa.gov, updated September 9, 2025 (accessed April 28, 2026)
Preparing Your HVAC System for Summer Heatwaves, trane.com, published April 8, 2024 (accessed April 28, 2026)
The Winter/Summer HVAC Switch: How To Prep Your System For Hot Months, Bill Miles, antonshvac.com, October 5, 2023 (accessed April 28, 2026)
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