Make sure it's set to "Heat," the target temperature is above room temperature, and the display isn't blank (replace batteries if it uses them). If it's a smart thermostat, check it hasn't lost Wi-Fi connection or been put in a hold/vacation mode by mistake.

Furnaces have their own power switch, usually a light-switch-looking toggle near the unit or at the top of the basement stairs — make sure it hasn't been bumped off. Also check your breaker panel for a tripped breaker labelled "furnace" or "HVAC."

A badly clogged filter can restrict airflow enough to trigger a safety shutoff. If yours hasn't been changed in a few months, swap it and see if that resolves the issue.

Most modern furnaces have a small window showing an LED that blinks in a pattern (a code) when something's wrong. Count the blinks/pauses — that code helps us diagnose the issue faster over the phone, so have it ready when you call.

If other gas appliances (stove, water heater) also aren't working, the issue may be at the gas supply level, not the furnace itself.

If your water heater has a visible pilot light window, check whether it's lit. Relighting instructions are usually printed on a sticker on the unit itself — follow those exactly. If it won't stay lit, that's a sign of a failing part and worth a service call rather than repeated attempts.

Electric tank units and most tankless units rely on power in addition to gas. Check your breaker panel for anything tripped.

Tank water heaters need time to recover after back-to-back showers or a load of laundry plus dishes. If it's just slow to reheat rather than completely cold, that may be normal for your tank size and household demand — ask us about sizing if it happens often.

Popping or rumbling sounds usually mean sediment buildup. Any visible water pooling at the base of the tank means it's time to call us — don't wait on a leaking tank.

Same starting point as furnace issues — confirm it's set to "Cool" below room temperature, and check whether the filter is clogged and restricting airflow.

Make sure the outdoor condenser isn't blocked by plants, debris, or a fence panel, and that the fan inside is actually spinning when the system's running. A unit caked in dirt or grass clippings loses efficiency fast.

Ice buildup usually means restricted airflow or a refrigerant issue. Turn the system off (switch to fan-only or off entirely) and let it fully thaw before calling — running it iced up can damage the compressor.

AC units often have their own dedicated breaker plus a small disconnect switch or pull-out block right next to the outdoor unit — both need to be on.

Leave the house, don't operate any switches or appliances on your way out, and call your gas utility's emergency line and us from outside. Never try to locate or fix a gas leak yourself.

Get everyone outside into fresh air immediately and call 911, then us. Don't go back in to investigate.

Shut the system off at the breaker if it's safe to reach, and call us. Don't attempt to open up or inspect the unit yourself.

A bulging tank can fail suddenly. Shut off the water supply and gas/power to the unit if you can safely access the valves, and call us right away.