Some furnace problems can wait until Monday. A few mean shut the system off right now, and one means leave the house. Knowing which is which is worth more than any troubleshooting tip.

Leave the House Immediately

Two situations are not repair calls until everyone is outside.

A gas smell. Rotten eggs or sulfur means a gas leak. Get everyone out, do not touch light switches or garage door openers, do not start a vehicle in an attached garage, and call from outside. Utility and emergency services first, then us.

A carbon monoxide alarm. Treat it as real every time. Get outside, call emergency services, and do not re-enter until someone qualified says it is clear. CO is colorless and odorless, and symptoms — headache, dizziness, nausea, confusion — resemble the flu, which is exactly what makes it dangerous.

Never assume an alarm is faulty because nobody feels ill. That reasoning has killed people.

Shut It Off and Call Now

These are emergencies for the equipment or your safety, but you are not evacuating.

A burning or electrical smell that persists. A brief dusty smell on the first heating cycle of the season is normal — burning insulation or hot metal is not.

Loud banging or booming at ignition. This usually means gas is accumulating before it lights. It is hard on the heat exchanger and it can be dangerous.

Grinding or metallic screeching. Bearings failing or something contacting the blower wheel. Running it further turns a motor replacement into more than that.

Visible soot around the furnace or vents, which indicates combustion problems.

Water pooling around a condensing furnace, which can damage the unit and whatever is beneath it.

In each case, shut the system off at the thermostat and the breaker, then call our emergency heating repair line.

Urgent, But Not Dangerous

No heat during a hard freeze is an emergency for a different reason: your plumbing is at risk.

Hill Country homes are not built like homes in cold climates. Supply lines run through unconditioned attics and along exterior walls. A house that loses heat during a sustained freeze can end up with burst pipes, and the water damage costs far more than the furnace repair.

If the house has vulnerable occupants — infants, elderly residents, anyone with a medical condition — that also moves a no-heat call up the priority list regardless of outdoor temperature.

While you wait: open cabinet doors under sinks on exterior walls, let a faucet drip, and close off unused rooms to concentrate whatever warmth remains.

Can Wait for a Scheduled Visit

Plenty of furnace problems are genuinely not urgent.

Uneven heating between rooms is usually a duct or insulation issue and has probably existed for years. Reduced airflow is often a filter. Higher-than-expected bills indicate efficiency loss, not danger. A thermostat that seems inaccurate, or a furnace that runs longer than it used to, are both worth addressing but not tonight.

Short cycling sits on the line — it is hard on the equipment and worth prompt attention, but it is not dangerous.

Check These First

Before calling for no heat, three things resolve a meaningful share of calls: confirm the thermostat is set to heat and above room temperature, check that the breaker has not tripped, and check that the furnace door panel is fully seated. Most furnaces have a safety switch that prevents operation if that panel is loose.

Also confirm the gas is on if other gas appliances are out too.

Preventing the Emergency

Almost every no-heat call we run in January was findable in October. Igniters, flame sensors, pressure switches, and limit switches give warning if someone is looking.

Fall furnace maintenance catches them, and our Care Club maintenance plan adds priority dispatch for the days when everyone in the county calls at once.

For anything urgent, call (830) 240-1835 or contact 72 Degrees.