Furnace not heating? Here's what to check first

Before you call, there are a few safe checks worth trying. A surprising number of "no-heat" calls come down to a thermostat setting, a tripped switch, or a clogged filter. Here's what to check first — and the warning signs that mean you should stop and call right away.

Safe checks to try first

• Thermostat. Confirm it's set to Heat and the target temperature is above the current room reading. If it's battery-powered, try fresh batteries.
• Power. Check that the furnace switch (it looks like a light switch near the unit) is on, and that the breaker hasn't tripped.
• Filter. A clogged filter chokes airflow and can shut the furnace down on a safety. If it's dirty, replace it.
• Vents and registers. Make sure supply and return vents aren't blocked by furniture or rugs.
• Furnace door. Many furnaces won't run if the blower-compartment door isn't fully closed.

Stop and call right away if…

• You smell gas. Leave the home immediately and call us — or your gas utility — from outside.
• You see a yellow burner flame instead of crisp blue, which can signal a combustion problem.
• The furnace keeps shutting down after a single reset, or you hear booming, banging, or grinding.
• Your carbon-monoxide detector alarms. Treat it as an emergency.

Why no-heat is an emergency in Minnesota

When it's below zero, a home without heat can drop to dangerous temperatures fast — and frozen pipes add expensive damage on top of the discomfort. That's why our furnace service prioritizes no-heat calls, and why we recommend a fall tune-up to catch problems before the coldest night. A maintenance plan bundles those checkups and adds priority scheduling when you need us most.

When it's time to think about replacement

If your furnace is past 15 years and the no-heat calls are becoming a pattern, it may be time to compare repair against a high-efficiency replacement — our repair-or-replace guide walks through the decision, and we're glad to give a free second opinion on any quote.

Frequently asked questions