The last thing any homeowner wants it to wake up at 3AM to a freezing cold house. If your furnace shuts down during a winter like many have experienced this year, you may also face costly repairs to burst water pipes, water damage, and even mold. But what can you do? Modern gas furnaces are not only energy efficient but also far more complicated than those from the 1990s. Furnace shut-downs that might have once been caused by a dirty thermocouple now involve smart systems that auto-test combustion air inducers, electronic ignition sensors, pressure switches, and exhaust flow monitoring.
Don’t panic. Even with all this complexity, there are a few basic things you can do to prevent your furnace from leaving you in the cold. To help make this more of a practical guide that you can really use, we’re going to arrange these tasks from the most basic to the more complicated.
How to Keep Your Furnace from Breaking Down
1. Check your thermostat batteries. Because programmable and smart thermostats are powered by batteries, it’s good idea to check once in a while to see how much charge is left. Most thermostats will show a flashing icon if their batteries are running low or need to be replaced.
2. Review your thermostat’s manual and check the settings. Though smart thermostats are very good at prompting the user, the old programmable ones are not. In either case, checking over thermostat settings, especially in areas that suffered through ice storms and blackouts, will allow you to make sure your thermostat is working fine. Check that your thermostat has been set to “heat” and that it’s set to a temperature high enough for the furnace to come on. Believe it or not, roughly 33% of homeowners never bother to set or override the programming features of their thermostats. While this might not cause your furnace to shut down, it will keep your heating bills high.
3. Change the air filter regularly. If your furnace is firing up but there’s very little air blowing through the vents, one likelihood is that the air filter needs to be changed. Air filters trap dust, hair, and other particles in the air. Over time, the filter gets so full of stuff that it restricts air flowing through your furnace system. For most residential heating systems, air filters should be changed every 3 months with the MERV-type specified by the manufacturer.
4. Keep the return vents from being blocked. Again, if your furnace is working hard but there’s little air flowing —and you just changed the furnace filter — check to make sure the return vents are not covered by carpeting or blocked by furniture. Return vents suck in cold air from rooms and take it to the furnace. Keeping the area around them open will circulate heated air more efficiently throughout your home.
5. Clean dust and pet fur from return vents. Dust bunnies, pet hair, and even houseplant leaves can easily get pulled into and onto return air vents, blocking them. Depending on your home (and your lifestyle) vacuum them off weekly. This keeps them from getting covered or clogged and it prevents even more dust from clogging your furnace filter.
6. Make sure nothing blocks the furnace exhaust or fresh air intake. Not all furnaces vent through chimneys. Many newer furnaces have their fresh air intakes and exhausts run through the side of the home and sometimes windblown leaves and insects can restrict air flow. In some cases, exhaust gasses can even be sucked into the fresh air intake and reduce the amount of gas being burned. Depending on how the exhaust pipe is set up, ice can block the furnace exhaust. In these instances, you might want to consult a licensed technician about possible venting solutions.
7. Check over and tidy up your furnace at least once a year. Best done before firing up for winter, turn off the circuit breaker to the blower and set the thermostat to “off”. Next, open any access panels to burners or heating elements and carefully vacuum up any signs of ash, fine debris, or even insects. Also, check wiring harnesses to make sure they have snug and secure connections. Next, check the blower. Over time, blowers collect heavy coatings of dust on their blades and the motor itself, restricting the air flow and increasing wear to the motor. Dust build-up can be due to poor air filtration or leaks in the blower compartment. You’ll want to open the blower compartment and clean out any dust or dirt that has accumulated. If your blower blades are covered in dusty-fuzz, then the blower should be removed and cleaned. This is certainly a difficult and messy job so be sure to take your time.
8. Clean out the condensate drain. Yes, gas furnaces actually produce water! On high efficiency gas furnaces, water condenses out at the power exhaust and drains away into a tube. Like condensate coming out of an air conditioner, mold can clog the drain tubing. If that happens, the water can back up into the power exhaust and stop your furnace cold. Each year before the heating season begins, detach the drain pipe from the rubber tube coming out the power exhaust. Next, pour a cup of vinegar into the drain pipe. Blow into the drain pipe to help keep the line clear (do NOT blow into the rubber tube connected to the power exhaust). Keep a bucket handy when disconnecting the rubber tube from the drain pipe. The drainage system holds nearly a quart of water in the drain line and it usually smells bad.
But I have an electric furnace! While electric furnaces are among the most expensive systems to have, they’re very easy to care for because their main enemy is dust and dirt. Regularly changing the air filter should keep the unit running smoothly.
It’s making noises! If your blower squeaks or whines when it’s running, relax. There are usually several causes but there’s a good chance you can figure them out. Before you begin looking, be sure to turn off the breaker to the blower and set the thermostat to OFF.
How to Fix a Noisy Furnace
- Fix loose screws. Vibration can shake loose screws over time and make the metal squeak. Locate the loose screws and just tighten the screws into place.
- Change the filter. Whiney blower noise is a good indicator that the blower is pulling too way to hard and not getting much air flow. The problem is probably that the air filter is thoroughly clogged and needs to be replaced.
- Refill the oil reservoirs. If the blower motor is squealing, buzzing, and hot to the touch, your furnace may need oil. Blower motor bearings should be kept in a continual bath of oil, but the reservoirs dry out after a few years and need to be refilled. This is done by pouring oil into little ports located at either end of the motor shaft. Though it’s cheap and easy and makes your system last years longer, the process of pulling the motor out can take a lot of time and get very messy.
While all of these tasks are things a homeowner can tackle, it’s always a good idea to contact a licensed professional HVAC service if you feel in over your head. Plus, a qualified technician can also find problems before they become disasters and keep your furnace system running at peak efficiency all winter long.