Heat out during a storm: what to check before you call

The three checks

The thermostat first: confirm it is calling for heat, the setpoint is above room temperature, and — if it takes batteries — that they are not dead. A blank screen in a cold house is often just batteries.

Then the breaker. Even gas equipment needs electricity for controls and the blower, so a tripped breaker stops a gas furnace as completely as an electric one.

Then the emergency shutoff. It looks exactly like an ordinary light switch, it is usually at the top of the basement stairs or beside the furnace, and it is switched off by accident more often than anyone expects.

Why to stop restarting it

If those three do not solve it, resist the urge to keep cycling power. Modern furnaces lock out after a set number of failed ignition attempts — a deliberate safety behaviour, not a fault.

Repeated attempts can also clear the diagnostic codes that would have told a technician what failed, which makes the visit longer and the diagnosis less certain.

Protecting the house while you wait

Let a faucet drip, ideally at the fixture furthest from where water enters the house. Moving water is far harder to freeze than standing water, and a burst pipe is a much worse problem than a cold night.

Open the cabinet doors under sinks on exterior walls so household heat reaches the pipes there.

Close doors to rooms you are not using and gather in one space. Concentrating the remaining heat keeps one room genuinely comfortable rather than the whole house marginally less cold.

If you use a space heater, keep it well clear of anything combustible and never run an oven for heat — that is a carbon monoxide risk, not a heating strategy.