The HVAC is the unsung hero of your home. It keeps it warm when it’s freezing, cool during brutal summers, and comfortable through every in-between. As summer turns to fall, it deserves some TLC to keep running smoothly—and avoid a mid-winter meltdown. With harsher winters as much a symptom of climate change as hotter summers, it’s more important than ever to ensure your system is ready for the cold.
Maintenance, however, is about more than comfort. The U.S. Energy Information Administration estimates that heating can account for nearly 45% of a household’s energy use. Meaning? A well-maintained system can keep your home cozy—and save money and emissions in the process.
If you don’t think your HVAC needs a look, think again. Plenty of folks subscribe to an “if it ain’t broke” approach to preventative maintenance. But, according to Karen Balko, COO for Vector Heating, Cooling, Plumbing, and Electrical, that kind of thinking can be costly. A system, she says, should be treated like your car: “Regular tune-ups prolong the life of the equipment and reduce costly surprises.”
The good news: Showing your system a little love in the fall goes a long way. Replacing filters, checking vents, sealing drafts, and scheduling a tune-up can keep things humming efficiently until spring. Here’s what to do—and what to avoid—to keep your home comfortable and energy bills low.
Do: Inspect thermostats, filters & vents
Most HVAC maintenance should be left to the pros. But there are a few quick, effective things you can do to get your system system ready for the temperature drop. “Systems collect dust, dirt, and moisture all year long—and that buildup can hurt efficiency, indoor air quality, and even cause mold issues if left unchecked,” says Adam Ross, Executive Director of the South Florida Academy of Air Conditioning and owner of Aircon Repair.
- Change filters
Your HVAC’s filter is your first line of defense against dust, allergens, and debris. If it’s clogged, airflow is restricted, the system works harder, and indoor air quality suffers. According to EnergyStar, filters should be swapped out at least every three months—more often if you have pets, allergy-sufferers, or smokers in your home. Not sure if it needs replacing? If the duct-facing side is caked in dust, replace it.
The type of filter also influences how often you’ll need to change it, says Ian Williams, an EPA-certified HVAC technician with Service Experts. A basic one-inch filter might only last a month, while higher-efficiency filters, which are between 4 and 5 inches thick, might last three to four.
When choosing a filter, look at the MERV rating (Minimum Efficiency Reporting Value). A rating between 8 and 13 is ideal for most homes. Higher ratings mean more particles trapped—but check your system’s manual to make sure you’re using the right type. - Check vents & registers
Closed or obstructed vents force your system to work harder, says Ross. Do a quick sweep of your home to ensure vents are open and not blocked by rugs, curtains, or furniture. - Clean around units
Airflow, both inside and out, is one of the key factors of an efficient home. For indoor units, clear at least two feet of space around a furnace or air handler. Vacuum up dust and remove clutter like boxes or household supplies that might be blocking vents or intakes.
For outdoor systems, pick up any leaves, grass clippings, or branches near the unit. Trim back shrubs and plants so there’s at least least 2 to 3 feet of clearance from the unit. This helps ensure proper airflow and makes general maintenance easier. - Test your thermostat
Before the first cold snap hits, switch your thermostat to ‘Heat’ or ‘Auto’ mode and give it a test run. If your home feels colder than expected or if the system doesn’t turn on, the thermostat is often the issue, says Williams. Turn the heat on for about 20 minutes to make sure everything’s working properly. If you hear weird noises or smell anything unusual, contact a service company to handle the problem early.
Do: Let outdoor units breathe
Unless you have trees raining debris onto your system, there’s usually no need to cover it. In fact, most manufacturers advise against it. “Outdoor HVAC units were built to be kept outside, so temperature changes won’t matter as much,” says Williams.
In fact, covering your unit can sometimes do more harm than good. Plastic tarps or airtight seals can trap moisture, which leads to rust, corrosion, and mold. If you’re worried about debris, a light mesh cover can offer protection without restricting airflow.
If you have a heat pump, never cover it because that will hinder its ability to pull ambient heat into the house during the colder months.
Do: Schedule a fall tuneup
The average homeowner can handle filters and thermostats—but not burners, gas connections, or heat exchangers. That’s where the pros come in. Experts scheduling maintenance in early September to avoid the seasonal rush. “It’s very important, especially in some parts of the country that get as cold as they do,” says Williams. “During the fall tune-up, a professional should look at all the electrical, venting or flue pipe, and check the gas connections if it’s a gas furnace.”
A good technician will also clean the units, including the blower motor, which powers the fan that circulates air. According to Williams, even one-eighth of an inch of dust buildup can reduce efficiency by up to 30%. Skipping this step can lead to costly mid-winter breakdowns or dangerous carbon monoxide leaks.
Don’t: Overlook air sealing
A well-tuned HVAC is only half the equation. The other half? Keeping the warm air inside. That’s where air sealing comes in.
Air sealing is basically the process of identifying and sealing any gaps where heat escapes in the winter or cool air escapes in the summer. Common problem areas include window and door frames, spots where pipes or wires enter the home, crawlspaces, fireplaces, and garages. “Check windows, doors, and garage doors to make sure they close tightly,” says Williams. “Inspect seals and use draft stoppers to help block any problem areas where you might be losing heat.”
One of the biggest offenders: The attic. According to the Department of Energy, poor insulation in attics, walls, and floors can account for up to 31% of a home’s heat loss.
If you’re unsure where your home is leaking air, consider hiring an insulation specialist or scheduling a Home Energy Audit. An audit can also evaluate HVAC performance, appliance performance, and other sources of waste.
Do: Think about your system’s age
HVAC systems don’t last forever. Fall is a smart time to take stock of your system’s lifespan—before winter puts it to the test. “General wisdom is that a system will last between 10 and 15 years as long as it’s being properly maintained,” says Williams. “If yours is approaching the upper end of that range, replacing it before a cold snap hits may prevent costly breakdowns.”
To decide whether to repair or replace an older unit, use the HVAC industry’s $5,000 rule: Multiply your system’s age by the estimated repair cost. If the total is more than $5,000, replacement might be the most cost-effective.
Do: Optimize your environment
As more weather fluctuations means more stress on home systems, it’s important to take efficiency steps to lessen the burden. After all, heating a home is hard on an energy bill. Here are some ways to stay warm in the winter that don’t involve reaching for the thermostat.