Turning on a heater after a long time can yield an unwelcome surprise. Imagine it’s the season’s first wintry day. It’s chilly enough in your house that you turn on the heat. After about thirty minutes, you realize that you’re still cold. You check your thermostat, only to find that the heat is on, but there doesn’t seem to be anything happening. The day’s forecast calls for even colder weather to come, and the thought of being without heat has you in a frenzy.
Of course, you could call an HVAC technician for an emergency house call but considering that others invariably have the same problem, you may not get help for quite some time. To avoid this uncomfortable scenario, it’s a good idea to perform some annual furnace maintenance in advance of winter. Here’s how.
Start By Making Sure You Have a Clean Filter
Plenty of dust can collect on the furnace’s filter during use, and one of the easiest ways to ensure your system’s optimal performance is to replace the filter. So, before you turn your heat on for the winter, choose the right furnace air filter and swap it out for the old one. Experts recommend that you replace your filter at least once every three months. But for maximum efficiency and to prevent thick dirt buildup on your filter, it is a good idea to check it monthly and replace it as needed.
Keep in mind that the standard matted-fiberglass filters found in most furnaces are designed primarily to protect the furnace from large particles of dust — they won’t block the microscopic particles that are most irritating to lung tissue. Pleated filters, which pack more material in the same amount of space, do a better job. For even greater filtration, consider upgrading to a pleated media filter or an electronic air cleaner, both of which can trap more than 95 percent of airborne dust, compared to as little as 20 percent for a standard flat filter.
Pro Tip: As Richard Trethewey explains, in a forced-air system, contaminants like allergens, dust mites, and pet dander get pulled into the return air and pushed right back into your living spaces. “During the winter, all the air that your family is breathing comes through this filter,” Richard says. That’s why checking your filter before turning on the heat for the season is one of the most impactful steps you can take for both your furnace’s performance and your family’s indoor air quality.
Run Your Heat Briefly in the Fall to Check for Issues
Another good idea for winter furnace prep is to ensure that your heating system runs. The best test is to turn your system on in the fall and run it above your home’s room temperature. Once the system starts, listen for unusual noises and check for strange odors. Initially, you may detect a burning smell, which could be something as simple as burning dust that’s found its way into the system. It will go away after running the heat for a while.
Odors that aren’t normal are those that smell like burning plastic or electrical wiring. In such instances, getting an inspection by a professional is a good idea. An expert can also perform an extensive furnace cleaning on more intricate parts of the system.
For dust on the surface of your furnace, you can wipe it away with a damp microfiber towel.
Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, compares furnace neglect to skipping car maintenance: “People wouldn’t dream of driving their car thirty thousand miles without an oil change, a tune-up and a new air filter. Yet that’s exactly how they treat their heating and cooling systems.” Without regular servicing, heating systems burn more fuel and are more likely to break down.
Install a New Thermostat
Another consideration as you prep your furnace for winter is to get rid of that old thermostat and replace it with an energy-efficient one. You can choose a programmable thermostat or upgrade to a smart thermostat.
Both kinds of thermostats give you greater control over your home’s energy use. With a programable thermostat, you can set temperatures and times. Then, throughout the day, the thermostat will control your home’s heat levels overnight and while you’re away at work. A smart thermostat will do what a programable one will do, but the advantage is that you can control it from your smartphone or even a smartwatch. So, if you forget to program your thermostat while on the go, you can remedy the problem, so you won’t have to come home to a cold house.
When installing a new thermostat, keep placement in mind. As the Ask This Old House team advises, never mount a thermostat near a fireplace—even an inoperable one—on an outside wall, or where direct sunlight can hit it, as any of these can throw off the temperature reading. An interior wall away from heat sources and drafts is the ideal spot.
Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, notes that many programmable thermostats never get used to their full potential: “Some of the first generation of programmables were painful to use. People got fed up. They’d just press the ‘hold’ button and do it manually.” Smart thermostats changed everything by connecting directly to your phone and adapting to your schedule.
Energy Savings Tip: According to TOH Magazine, setting your thermostat back 7 to 10 degrees for eight hours while you’re away each day can shave up to 10 percent off your yearly heating bill. The optimal temperature for energy savings is 68 to 70 degrees F. However, if you have cast-iron radiators or radiant floor heating, don’t touch the dial—you’ll waste more energy by changing the temperature than if you left it alone.
Check for What’s Not So Obvious
Sometimes problems with your furnace can be simple to fix but not so obvious to detect. Here are some things to check for that may not be readily apparent.
Look for a pilot light
One problem with your furnace may be that your pilot light isn’t lit. Solving this issue may be as simple as relighting it with a flame or pressing an ignitor button. However, if you smell gas or can’t figure out how to light the pilot, it’s best to call in a pro.
Examine the circuit breaker
Another not-so-obvious problem may lie in your power supply. Before you panic and assume your heating system needs repair or replacement, check the circuit box. Someone may have turned this switch off, particularly if you’ve recently had repairs done in your home. Or the circuit may have shut off for some other reason, possibly even be a short in the wiring. In such instances, your problem may not be your HVAC system at all and you’ll have to call an electrician.
Pro Tip: Richard Trethewey, TOH plumbing and heating expert, notes that many manufacturers now offer kits that allow an HVAC contractor to convert a standing pilot light to an electronic spark-ignition system. “The chief advantage of electronic ignition is lower fuel consumption and greater safety because there’s no gas to leak if the pilot flame accidentally goes out,” he says. However, he cautions that low gas pressure can also be a culprit — something he’s been hearing more and more about — and in that case, switching to spark ignition wouldn’t much matter.
Hire a Professional to Perform an Annual Inspection
You can do a few things to get your furnace ready for winter. However, it may be ideal to hire a professional to perform an inspection on your system to ensure it is functioning and ready for winter use. Here are a few essential tips when calling in an HVAC pro.
- Start by checking reviews online
- Find a nationally certified HVAC contractor
- Ask friends, neighbors, and colleagues for references
- Discover how much the inspection will cost
- Check for special offers to save money
- Interview the companies you’re considering hiring
- Get an estimate in writing
If you hire a professional, they may determine that you need a new furnace. New furnace costs, including the new unit and labor, could run between $1,500 and $9,500, depending on the type of furnace you need. If a new furnace is outside your budget, some companies offer pricing plans that allow you to finance the purchase of a new system.
Check All Fire and Carbon Monoxide Detectors
Since a faulty furnace can cause a fire or release carbon monoxide into the air, it is a good idea to ensure that your smoke detectors and carbon monoxide detectors are working. Start by replacing the batteries in them, and consider upgrading to newer models if they’re outdated.
When upgrading, consider hardwired combination smoke and carbon monoxide detectors with battery backup. As demonstrated on a This Old House project, hardwired units communicate with each other throughout the house — so if a detector goes off in the basement near your furnace, every unit in the home sounds the alarm, even on the second or third floor. Newer models with voice alerts will also tell you whether the threat is fire or carbon monoxide, so you can react accordingly.
