Blog

HVAC no-heat call script: gas smell or CO alarm means get out first, then check the thermostat and book the visit

By Sharrk Team · October 18, 2026

A good HVAC no-heat call script puts safety first: if the caller smells gas or a carbon monoxide alarm is going off, they leave the house and call 911 or the gas utility from outside, and only then do you check the thermostat, power and filter and book the visit. Sharrk's AI voice agent asks those questions in the same order on every call, 24/7, and live-transfers real emergencies to your on-call tech.

The rest of this post is the word-for-word script, why each step is there, and how to set it up so no "my heat is out" call goes unanswered this winter.

What should you say first on a no-heat call?

Open with the safety screen, before you ask for a name or address. A caller who smells gas should not be standing in the kitchen giving you their ZIP code.

Agent: "Thanks for calling [Company], this is [Name]. I'm sorry your heat is out, we'll get you sorted. Before anything else: do you smell gas, like rotten eggs, or is a carbon monoxide alarm going off?"

If they smell gas: "Okay, please leave the house now with everyone inside. Don't flip any light switches or use your phone until you're outside and away from the smell. Once you're out, call 911 and your gas company. Don't go back in until they tell you it's safe. Please hang up now and call us back once you're safely outside."

That wording follows Pennsylvania's utility regulator, which tells people who smell gas to leave immediately, not turn lights on or off, avoid causing a spark, and call 911 and the gas utility "from a safe distance, away from the odor."

If a CO alarm is sounding: "Please get everyone outside into fresh air right now, then call 911. Stay outside until the fire department says it's clear."

The U.S. Consumer Product Safety Commission says that if you suspect CO poisoning you should "get outside to fresh air immediately, and then call 911," and it reports more than 200 accidental non-fire CO deaths a year in the U.S. tied to consumer products. Kidde's alarm guidance adds: account for everyone and stay out until responders give the all clear.

If anyone feels sick: Ask, "Is anyone in the home dizzy, nauseous, confused or getting headaches?" The CDC lists headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion as the most common CO symptoms and notes they are often described as "flu-like." A yes here gets the same answer as the alarm: outside, then 911.

Only when all three answers are no do you move on.

What quick checks can a caller safely do?

Keep it to checks a homeowner can do without opening the furnace. Carrier's own troubleshooting page for a furnace that won't turn on starts with the same three:

1. Thermostat. "Can you look at your thermostat? Is it set to Heat, and is the set temperature higher than what the room is now?" If the screen is blank, ask whether it takes batteries.
2. Power. "Is the switch on or near the furnace turned on? And is any breaker in your electrical panel tripped?" Carrier says to make sure the furnace switch is on and to reset a tripped breaker by switching it off and back on.
3. Filter. "When was the filter last changed?" Carrier recommends checking it every four weeks. A badly clogged filter is worth noting for the tech, but don't walk a caller through pulling panels.

If heat comes back, offer a maintenance visit. If not, keep going. Never ask a caller to relight a pilot, open burner panels or reset a gas valve.

How do you triage who needs a tech tonight?

Not every no-heat call is the same job. Ask two questions and write the answers down word for word:

• "Is anyone in the home elderly, an infant, or someone with a medical condition that the cold affects?"
• "About how cold is it inside right now?"

The CDC names "older adults with inadequate food, clothing, or heating" and "babies sleeping in cold bedrooms" among the people most often affected by hypothermia. A house with an infant or an older adult and a falling indoor temperature is the call you live-transfer to your on-call tech or book in the first available slot. Your own policy sets the cutoffs; the script just makes sure the question gets asked every time.

What details should you capture before booking?

Get everything the tech needs so the visit starts with diagnosis, not questions:

• Name, best callback number, and service address with any gate code
• Owner or renter (and the landlord's contact if renting)
• System type: gas furnace, heat pump, boiler, or electric
• Approximate age and brand if they know it
• What happened: no air, cold air blowing, short cycling, noises, error codes
• What they already checked (thermostat, switch, breaker, filter)
• Pets or access notes

Then quote your after-hours terms plainly. If you charge an emergency or after-hours trip fee, say so before you book; our guide to HVAC after-hours service call fees covers how other shops word it.

How do you close the call?

Agent: "Okay, I have you down for [day, arrival window] at [address]. [Tech] will call when they're on the way. If you smell gas or your CO alarm goes off before then, leave the house and call 911 first. Anything else I can help with?"

Repeating the safety line at the end is deliberate. Conditions change between the call and the visit.

How does Sharrk handle no-heat calls?

Sharrk's AI voice agent answers every call 24/7 and follows this script in order: safety screen, quick checks, triage, details, booking. When a caller reports a gas smell, a CO alarm or a vulnerable person in a cold house, the agent gives the safety instructions and then live-transfers to your on-call person, cold or warm. Everything else gets booked onto Sharrk's calendar, Calendly, Cal.com or ServiceTitan, where it can use real arrival windows by business unit and job type.

You build it with Mako, Sharrk's AI assistant. Tell it in plain English, "Add a no-heat script: ask about gas smell and CO alarms first, transfer emergencies to Mike, then book," and Mako builds the agent, shows each change on an Apply card, and lets you Undo anything. Load your service area, hours, fees and FAQs into a knowledge base so the agent answers pricing questions the way you would.

Every call is logged with a transcript and recording, the answers (system type, occupants, what they checked) are pulled into fields, and you get a text or email alert. See how it fits a heating shop on our AI receptionist for HVAC page, or compare plans on pricing: Sharrk Core is $99 a month with every feature live.

You can start free and build and test the whole script with Mako, no card needed, or book a demo.

Sources

• Pennsylvania PUC: Gas Emergencies (checked October 18, 2026)
• U.S. CPSC: Carbon Monoxide Information Center (checked October 18, 2026)
• Kidde: What should I do when my carbon monoxide alarm sounds? (checked October 18, 2026)
• CDC: Carbon Monoxide Poisoning Basics (checked October 18, 2026)
• CDC: Preventing Hypothermia (checked October 18, 2026)
• Carrier: Furnace Not Turning On (checked October 18, 2026)

Related on Sharrk: AI receptionist for HVAC · AI answering service · HVAC answering service guide

Start free, no credit card · See pricing · Book a demo