Turning the heat on for the first time this fall: what's normal and what isn't

That burning smell

Almost everybody notices it. Over the summer, dust settles on the furnace's heat exchanger (or on the backup heat strips in a heat pump), and the first time it heats up, that dust burns off. It smells like a toaster nobody's cleaned in a while.

That's normal, and it should fade within an hour or so. Crack a window if it bugs you.

What's not normal: a smell like hot plastic or burning wires, smoke coming out of the vents, or a burning smell that's still there the next day. Turn the system off at the thermostat and give us a call.

A rotten egg smell

Natural gas has no smell of its own, so the gas company adds one that smells like rotten eggs or sulfur. If you smell it near the furnace or anywhere in the house, don't troubleshoot. Get everyone out, don't flip any switches, and call 911 and Puget Sound Energy once you're outside.

Clicks, ticks and a whoosh

Ductwork expands as it warms up and can tick for a few minutes. You'll also hear the inducer motor spin up, a click as the igniter lights, and a soft whoosh when the burners catch. All normal.

A loud bang when the burners light, a screech from the blower, or a rattle that wasn't there last spring are all worth having looked at before the weather really turns.

It runs for a minute, then shuts off

If the furnace lights, runs for a few seconds or a few minutes, then quits and tries again, the usual suspects are a dirty flame sensor or a clogged filter. Change the filter first. If it keeps happening, it's a quick fix for a tech. Just don't keep resetting it over and over.

No heat at all? Check these first

The thermostat is on Heat and set a few degrees above the room temperature. New batteries if it takes them.
The furnace switch is on. It looks like a regular light switch, on the wall near the furnace or on the side of it. People flip it off by accident all the time.
The breaker for the furnace or heat pump hasn't tripped.
The front panel on the furnace is closed tight. There's a safety switch behind it.
The filter isn't completely clogged.

If all of that checks out and there's still no heat, that's our job. Call or text (425) 905-2855.

If you have a heat pump

A few things are normal for heat pumps and still surprise people their first fall:

The air from the vents feels warm, not hot. Heat pumps put out cooler air than a furnace, but they run longer.
On cold, damp mornings the outdoor unit stops, whooshes and puffs out steam. That's a defrost cycle.
If the thermostat has an "emergency heat" or "aux heat" setting, leave it alone unless the heat pump has actually quit. It runs the backup heat strips, and those are expensive to leave on.

Ten minutes of fall prep

Put in a new filter.
Test your carbon monoxide alarms, or put some in if you don't have them. With a gas furnace, water heater or fireplace, they're cheap insurance.
Clear leaves and fir needles away from the outdoor unit.
Make sure furniture and rugs aren't covering vents or returns.

And if your furnace or heat pump hasn't had a tune-up in a while, now's the time. Once the first real cold snap hits, everybody calls at once.