Winter is approaching, and preparing your furnace now involves more than just flipping a switch.
A well-maintained furnace keeps your home warm, cuts energy costs, and extends your heating system’s life. With a few expert tips and simple DIY tasks, you can get your furnace winter-ready.
Here are 14 practical tips to help you get started.
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1. Choose the Right Furnace Filters
Selecting proper furnace filters boosts efficiency and air quality. High-efficiency filters capture particles like dust and allergens but may restrict airflow if they are not compatible with your furnace.
Check your manual to select safe filters and find the recommended replacement frequency, usually every 1-3 months. If you don’t have the manual, look online using your furnace model number.
If you have pets or recent renovations, check and replace filters more frequently, as they clog faster. For reusable filters, use a proper cleaner, not just water, to remove buildup.
Install filters in the correct direction by following the arrows on the filter frame, pointing toward the furnace or blower motor.
Pro Tip: Use a smartphone calendar or smart home app to remind you when to change filters.
2. Inspect the Filter Housing and Seals
Inspecting the filter housing and seals is an important yet often overlooked maintenance task. Dust and debris can build up, and worn seals may cause air leaks, reducing efficiency and allowing unfiltered air to circulate.
Turn off the furnace for safety, remove the filter, and use a flashlight to check for gaps, dust buildup, or worn seals around the housing. Vacuum the area and replace any damaged seals to maintain an airtight fit.
Pro Tip: A thin layer of weatherproof adhesive on worn seals improves the seal and boosts furnace performance.
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3. Clean or Replace Vents and Grilles
Furnace air vents and grilles can clog with dust, pet hair, and debris, reducing airflow and efficiency. Regularly cleaning or replacing them is a simple DIY task that improves air quality and heating performance.
Use a vacuum with a brush attachment to clear dust and debris from vents and grilles. If vents are old, damaged, or hard to clean, consider replacing them to improve airflow and refresh the look of your rooms.
Pro Tip: Use a long-handled duster for hard-to-reach vents and magnetic vent covers to direct heat where needed.
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4. Calibrate Your Thermostat
After setting up your furnace and ducts, check that your thermostat is functioning correctly. Its location affects its accuracy, so keep it away from doors, windows, or heat sources that could cause false readings.
If temperatures seem inconsistent, check readings in different rooms and adjust using the average.
For smart thermostats, use the settings menu to recalibrate or reset them and regularly update the firmware. For non-smart thermostats, manually compare the reading to a reliable thermometer nearby.
If they differ, remove the cover, locate the calibration screw, and adjust it. Recheck after a few hours and make further small adjustments as needed.
Pro Tip: Use this infrared thermometer to quickly check room temperatures and adjust your thermostat for balanced heating throughout your home.
5. Adjust Dampers to Balance Airflow
After setting your thermostat, balance airflow for even heating by adjusting manual dampers on the ducts, typically found in the basement or attic.
Start by checking the temperature in each room. If some rooms feel too hot or too cold, adjust the nearby dampers. Turn the handles slightly to open or close them and change the airflow.
Make small adjustments and wait a few hours to see how it affects room temperatures. Repeat as needed, especially with seasonal changes.
Pro Tip: Mark damper positions with the date and any seasonal notes to easily readjust them each season, keeping room temperatures consistent.
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6. Seal Gaps to Stop Drafts
After balancing the airflow, check around your furnace for gaps or cracks that could cause drafts and reduce heating efficiency.
Address openings where ductwork enters walls or floors and seal them with caulk or weatherstripping. This helps maintain warmth and reduces the strain on your furnace.
Pro Tip: For small gaps, use a removable caulk. It provides a good seal and can be easily removed for future maintenance or repairs.
7. Use Ceiling Fans to Circulate Warm Air
After balancing airflow and sealing gaps, use ceiling fans to help distribute warm air during winter. Set ceiling fans to rotate clockwise at a low speed.
This direction creates an updraft, pulling cooler air up and pushing warm air down along the walls, making the room feel warmer without adjusting the thermostat.
To change the fan direction, use the switch on the fan base. For consistent warmth, keep all fans on the clockwise setting across all levels of the home. This helps maintain comfort and reduces the load on your heating system.
8. Clean the Flame Sensor Regularly
Maintaining warm airflow is important, but keeping your furnace running smoothly is just as vital. The flame sensor detects when the burner is lit, but dirt buildup can cause it to malfunction, leading to frequent shutdowns.
To clean it, turn off the furnace power and locate the flame sensor—usually a thin metal rod near the burners. Remove it with a screwdriver and gently clean it with an emery cloth or non-abrasive cleaner.
Avoid using soap and water, and wear gloves to prevent skin oils from transferring. Once clean, reattach the sensor and position it correctly.
Pro Tip: After cleaning, turn on the furnace to confirm it’s running smoothly. This helps catch issues early and prevent unexpected shutdowns.
9. Clean & Lubricate the Blower Motor
Keeping the blower motor clean and lubricated is key to maintaining efficiency and extending its life. Dust buildup can cause the motor to work harder, reducing furnace performance.
First, turn off the furnace power. Locate the blower motor and carefully remove it according to the manufacturer’s instructions. Use a soft brush or vacuum to clean dust and debris from the motor and surrounding area without disturbing the wiring.
Check if the motor has oil ports. If so, add a few drops of electric motor oil (not general-purpose oil) to keep it running smoothly. Be careful not to over-lubricate, as this can attract dust and cause buildup.
Pro Tip: Keep a maintenance log near the furnace to track cleaning, lubrication, and any unusual sounds to stay on top of potential issues.
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10. Maintain Furnace-Connected Humidifiers
To keep your home comfortable, maintain furnace-connected humidifiers regularly. Annual maintenance, usually at the start of the heating season, is crucial for optimal performance.
Turn off the furnace and the water supply to the humidifier. Remove and clean the water panel or filter with a disinfecting solution to remove mineral buildup.
Then, clean the water lines and reservoir to prevent mold and clogs. Regular cleaning keeps the humidifier functioning properly and improves air quality.
Pro Tip: Stock up on replaceable pads or filters at the start of the season for quick and easy replacements.
11. Check the Flue for Safe Venting
The furnace flue vents harmful gases like carbon monoxide outside and needs regular checks. Many basic inspections can be done from the attic or basement, so there’s no need to climb onto the roof.
Check inside the flue for rust, corrosion, or wear that could signal leaks. For minor maintenance, use a flexible brush to remove debris that might block the flue. Adding a flue cap with a screen can also help prevent future blockages and improve safety.
If you notice significant damage or are unsure about the flue’s condition, consult a professional to avoid exposure to dangerous gases.
Pro Tip: Use a smoke pencil or incense stick near the flue connections to check for leaks. If the smoke is drawn into the flue, it’s working properly. If it drifts away or back, there may be a draft issue.
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12. Install Carbon Monoxide Detectors
When preparing your furnace, protect your home from carbon monoxide (CO).
Install CO detectors on every level, including basements and attics, and place them near sleeping areas so you can hear them if CO levels become dangerous.
Avoid placing CO detectors near windows, vents, or fans, as airflow can affect readings. Regularly check the batteries and test alarms monthly to keep them functioning properly and ready to alert you to danger.
Pro Tip: Test CO detectors monthly by pressing the “Test” button. Replace detectors every 5-7 years, even if they seem to work fine.
13. Deep Clean Furnace Components
Regular deep cleaning of furnace parts is vital for efficiency and preventing breakdowns. While homeowners can do basic cleaning, a thorough deep clean should be performed annually.
For DIY tasks, check the drain line, pressure switches, and evaporator coil for dirt and debris that could cause clogs. Regularly clean the condensate pump to prevent leaks and mold.
Watch for signs like water puddles or strange noises, which could indicate hidden issues.
Pro Tip: Clean around the condensate drain line and pressure switch with an old toothbrush and a vacuum once a year to prevent blockages.
14. Conduct In-Depth Furnace Checks
After basic maintenance, an in-depth furnace checkup helps spot potential issues and maintain safety, especially for older systems.
Perform simple checks, such as listening for unusual sounds, observing flickering or yellow flames, and noting any strange smells.
These signs might indicate the need for professional help.
Additionally, tasks such as checking for gas leaks, inspecting the heat exchanger for cracks, and assessing combustion efficiency often require expert attention.
Pro Tip: If you’re unsure about in-depth checks, attend a local workshop or online webinar on furnace maintenance. This will build your confidence in handling basic tasks and knowing when to call a professional.
Prepare Your Furnace for Winter
Implement these 14 expert tips to ready your furnace for the winter, reduce heating costs, and prevent unexpected failures. Many tasks are manageable as DIY projects.
For complex or safety-related issues, seek professional help. Combining DIY maintenance with professional services will keep your furnace running efficiently all season.
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