Temperatures are getting close to freezing — in some cases they have already dropped below zero — and the last thing you want is to turn on your furnace only to find it doesn’t work.

Newer furnaces have light indicators on them that can tell you if there’s a problem. The lights will flash differently depending on what the issue is. There should be a sticker on the furnace that tells you what the different flashes mean. It might be behind a panel, so check the owner’s manual.

By doing so, you can tell your HVAC technician what the specific problem is, and they will know which tools and parts to bring on their service call. That can save crucial time — something that will definitely matter on a cold winter night.

If you haven’t already had your furnace serviced by a licensed HVAC technician, now’s the time. They’ll check all the different components of the furnace and make sure it’s up for the challenge of meeting your winter heating demands.

They will, for example, check the thermostat, the registers (to make sure they’re clean and not blocked), the flue, vents and fan. And if the furnace is gas, they will check the igniter. Sometimes sediment or dust can accumulate on the igniter, which stops it from working. Some homeowners think they need to replace the whole system when all that’s needed is a little cleanup.

A pro will also check the ducts to make sure they’re properly sealed so there are no air leaks. An HVAC pro or an energy auditor can determine how much air your system is losing, which could be as much as 20%.

If the ducts are accessible, as they are in an unfinished basement, they can be sealed with heat-resistant caulking, aluminum or metal-foil tape — not duct tape — or the original seal can be rebuilt.

But stopping an air leak isn’t always easy. Even finding it can often be a challenge. Plus, if the leak is in ductwork behind a wall or in the ceiling, the drywall will need to be taken down. Once the air leak is stopped, the next job is to replace, repair and repaint the drywall.

Replacing the air filter at least once every three months is standard, but every month is better. I’d do it every two weeks during a renovation.

It’s important to replace the filter every month in the cold season because the furnace pushes and filters more air, which means the filter gets clogged faster. A clogged filter doesn’t work, and it can wear out your furnace prematurely.

Natural gas is still king in forced-air heating systems, but it can have safety issues, such as gas leaks.

Every storey in your home should therefore have a carbon monoxide (CO) detector (have one directly outside bedrooms) — and you should test them every month. Natural gas is still king in forced-air heating systems, but it can have safety issues, such as gas leaks

Testing is easy. Every CO detector has a test button. To test the system, hold the test button down for two to five seconds. You should hear a loud beep. If it sounds weak, it’s time to change the batteries. Either way, the batteries need to be changed twice a year. A good time to do it is when the clocks get changed in spring and fall.

Some newer homes have CO detectors and smoke alarms hardwired into the home’s electrical system. But they must have a battery backup, no exceptions. All alarms need to be tested, hardwired or not.

Is hiring a pro to check your furnace worth the time, effort and money? Absolutely. If you don’t have hundreds of dollars just lying around, you might not see it that way, and I get that.

But if you think about the money you may be losing every month because of an air leak or because your system is too old or inefficient, it might help put things in perspective.

New Berlin Heating is the leading heating and cooling company in New Berlin, WI and the surrounding area. If you have any questions please give us a call at (262) 784-8889. You can also check us out on Facebook or Twitter