Check the Air Filter
A badly clogged air filter can cause the furnace to overheat and shut off, so replace it if it's dirty. It can be hard to tell with some filters, so consider installing an air filter gauge that lets you know when it's time to replace the filter.
Never Checking the Power on the Furnace
Never Checking the Thermostat
Check the Gasline Shutoff
Check the Door Switch
Check the door switch. Whenever you remove the access door on the furnace, a little safety switch shuts everything off. Sometimes this switch will stay turned off if the door isn't completely closed. Plus: Do you need a new furnace? You might not.
Check the Intake and Exhaust Pipes
Check the Condensate Line
High-efficiency furnaces produce water called 'condensate.' If the drain tubing for the condensate gets clogged, the furnace shuts off. Check the tubing and clear any clogs. Or, better yet, just replace the tubing.
Check the Cold-Air Returns
Get a Carbon Monoxide Detector
When heat exchangers crack or there's a leak in the exhaust pipe, deadly carbon monoxide can seep into your home's living space. That's why it's critical that you have a working carbon monoxide detector. You can buy two-in-one carbon monoxide and smoke detectors, or stand-alone units that you just plug into a wall (with backup batteries) for $20 to $40 at home centers.
Adjust the Dampers
Never Changing the Furnace Filter
What 'Efficiency' Means
An AFUE (annual fuel utilization efficiency) rating on a furnace tells you how efficiently the furnace turns fossil fuel into usable heat. An older-style furnace will have an efficiency rating of 56 to 83 percent, while a modern 'high-efficiency' furnace will have a rating of 90 percent or higher. That means 90 percent of the furnace's fuel becomes usable heat for your home, while the other 10 percent is lost with the exhaust up the chimney.
If you’re looking for the best furnace to purchase, energy efficient brands might be the best bet.
Do you have a room that’s a little colder in the Winter or warmer in the Summer? Check out this simple blower speed furnace boost trick.