What Counts as an HVAC Emergency? A Guide for London & St. Thomas Homeowners
Learn to identify true HVAC emergencies: gas smells, no heat in freezing weather, AC failure in heat waves, dangerous noises, and carbon monoxide alerts. 24/7 service with zero after-hours surcharge.
When your heating or cooling system fails in the middle of the night, it's easy to panic. But not every issue requires an after-hours emergency call. Hawana HVAC helps homeowners in London, St. Thomas, and surrounding areas understand what constitutes a true HVAC emergency — and what can wait until morning. As a TSSA-certified company with 138 five-star reviews, we prioritize real emergencies with zero after-hours surcharge.
We answer every call, day or night. No voicemail, no waiting until morning. If you're unsure whether it's an emergency, call us anyway — we'll help you decide over the phone at no charge.
Call for Emergency Service Immediately If You Notice:
1. You Smell Gas or "Rotten Eggs"
This is the most critical emergency. Natural gas is odorless, so utility companies add mercaptan giving it a distinct rotten egg smell. If you detect this odor near your furnace or anywhere in your home:
- Do NOT operate any electronics, light switches, or lighters
- Do NOT use your phone inside the house
- Evacuate everyone from the house immediately
- From a safe distance (neighbour's house), call Enbridge Gas emergency line at 1-866-763-5427
- After the utility secures the gas supply, call us for 24/7 furnace repair
2. No Heat During Freezing Temperatures
In a Southwestern Ontario winter, a complete loss of heat is a serious threat. When temperatures outside are below freezing, a home without heat can quickly become dangerously cold.
- Risk to Property: Frozen and bursting pipes can cause $10,000-$50,000 in water damage within 6-8 hours
- Health Risk: Hypothermia affects vulnerable family members, especially infants and elderly
- Our Response: Hawana prioritizes no-heat calls in winter — we're typically on-site within 60 minutes
3. No Air Conditioning During a Heat Wave
While often seen as a comfort issue, lack of cooling during an extreme heat advisory (30°C+ with high humidity) is a health emergency, especially for households with young children, elderly, or those with medical conditions.
- Heat exhaustion and heat stroke are serious health risks
- Can lead to hospitalization, especially for vulnerable individuals
- If anyone has respiratory or heart conditions, treat as immediate emergency
4. Loud Banging, Grinding, or Squealing Noises
Your HVAC system should operate with a gentle hum. Loud, sudden, persistent mechanical noises mean serious internal damage:
- Banging or Popping: Major ignition issue or broken component inside the combustion chamber
- Grinding or Scraping: Broken motor bearing or fan blade destroying itself
- Squealing: Failing blower motor, loose belt, or worn bearings
- Action: Shut off system at thermostat and breaker immediately — running damaged system can cause complete failure
5. Carbon Monoxide Detector Alarm
If your CO detector alarms, treat it as a real event — this is always an emergency.
- Evacuate your home immediately and call 911 from a safe location
- A malfunctioning furnace heat exchanger is a common source of CO leaks
- Symptoms: headache, dizziness, nausea, confusion, loss of consciousness
- Once fire department clears your home, call us for emergency furnace inspection
6. Visible Water Around Furnace or AC
While a slow drip might wait, significant water around your equipment is urgent:
- Could indicate a cracked heat exchanger (furnace) — carbon monoxide risk
- Could indicate frozen evaporator coil (AC) — can damage compressor
- Water damage to floors, walls, and belongings adds urgency
- Turn off system and call immediately if water is pooling
What Might NOT Be an Emergency (Can Wait for Regular Appointment)
Some issues, while frustrating, can wait for a regular service appointment without risking your safety or causing major damage:
Could be a blockage or damper issue, not system failure. Check if the vent is open and unobstructed.
Minor rattling can wait unless it's sudden and loud as described above. Often just loose panels.
If you can contain the drip with a pan, it's likely a clogged drain line that can be addressed during business hours.
Try changing batteries first. If that doesn't work, schedule daytime service — the system itself may be fine.
Try resetting once. If it trips again immediately, call for service. If it holds, monitor.
Usually a duct balancing or insulation issue, not an emergency. Can wait for regular appointment.
Emergency Steps: What to Do Before the Technician Arrives
Ensure Safety First
For gas smells or CO alarms, evacuate immediately. Don't wait to confirm the danger.
Clear the Area
Remove items stored near your furnace, water heater, or AC unit. Ensure clear path for technician.
Note the Symptoms
Write down: when problem started, any unusual sounds or smells, and which equipment is affected.
Find Model Numbers
Locate the model and serial numbers on your furnace, AC, or water heater — speeds up diagnosis.
Turn Off if Dangerous
For loud mechanical noises, turn off system at thermostat and breaker. For gas smells, leave it on for utility to test.
Call Us
Dial (647) 550-4220. We'll ask questions to prepare and dispatch the nearest technician.
Real Emergency Stories from London & St. Thomas Homeowners
"Our furnace died at 11 PM on the coldest night of January near White Oaks Mall in London. I called Hawana expecting a huge after-hours charge, but Abdullah came within an hour with zero surcharge. He diagnosed a failed ignitor, had the part in his truck, and had heat back on by midnight. No hidden fees, just honest work. This guide is spot on about what counts as an emergency. Saved our pipes and our family from freezing."
— Heath B. London ON · December 2025
"We smelled gas near our furnace in St. Thomas on a Sunday morning. I remembered this guide and evacuated immediately with my family. Called Enbridge first, then Hawana. The gas company found a small leak at a fitting. Abdullah arrived right after and repaired it properly. He explained everything and charged a fair price. No weekend premium, no panic pricing. This company saved us from a potential disaster. I can't recommend them enough for emergency response."
— Dell T. St. Thomas ON · November 2025
"Our AC died during that 35°C heat wave last July. My elderly mother lives with us near Port Stanley, so this was a real health emergency. Hawana came out at 8 PM, found a failed capacitor, and had the AC running in 45 minutes. No after-hours surcharge and they even gave us a senior discount. This guide helped me know it was a real emergency, not just an inconvenience. Mom stayed cool and comfortable thanks to their fast response."
— Firth K. Port Stanley ON · August 2025
Abdullah Ghzail – Owner & Lead TSSA-Certified HVAC Specialist
"I've responded to thousands of emergency calls across London, St. Thomas, and surrounding areas over my career. The number one mistake homeowners make is waiting 'until morning' when they smell gas or have no heat at -20°C. Don't gamble with your family's safety or your home's pipes. A frozen pipe can burst and cause $30,000+ in water damage in hours. If you're unsure whether it's an emergency, call us anyway — we'll help you decide over the phone at no charge. And remember, we never charge after-hours premiums. Same price at 3 AM as 3 PM."
Emergency vs. Non-Emergency: Quick Reference Table
Emergency HVAC FAQ – 2026
Unlike companies that charge after-hours premiums, Hawana HVAC charges zero surcharge for emergency service. You pay the same diagnostic and repair rates whether it's 2 PM or 2 AM, weekend or holiday. We believe safety doesn't wait for business hours, and neither should affordable service. Our diagnostic fee is $175, waived if you proceed with the repair. This transparency has earned us 138 five-star reviews from London and St. Thomas homeowners.
Ensure a clear path to your HVAC equipment. If possible, have the model number of your unit handy. For gas smells, evacuate immediately and call Enbridge first. Do not attempt to open or repair the unit yourself, especially if you suspect a gas or electrical issue. Turn off the system at the thermostat if you hear loud mechanical noises. Have your payment method ready to speed up the process once repairs are complete. Most importantly, stay calm — help is on the way.
YES, absolutely. If your CO detector alarms, treat it as a real event. Evacuate your home immediately and call 911 from a safe location. A malfunctioning furnace heat exchanger is a common source of CO leaks. Symptoms of CO poisoning include headache, dizziness, nausea, confusion, and loss of consciousness. Once the fire department has cleared your home, call us for an emergency inspection of your furnace before using it again. Do not re-enter until both authorities and we have inspected. CO is called the silent killer for a reason — don't take chances.
Any complete loss of heat when outside temperatures are below 5°C (41°F) is an emergency. In Southwestern Ontario winters with temperatures dropping to -20°C or lower, a home without heat faces immediate pipe freeze risk within 6-8 hours. Pipes can burst, causing $10,000-$50,000 in water damage plus mold remediation costs. Call for emergency service immediately, not the next morning. We prioritize no-heat calls in winter and are typically on-site within 60 minutes. For vulnerable households with infants or elderly, we respond even faster.
Yes, during extreme heat advisories (30°C+ with high humidity) when vulnerable people (elderly, infants, medical conditions) are in the home. Heat exhaustion and heat stroke are serious health risks that can lead to hospitalization. For mild summer days without vulnerable occupants, it can wait for a regular appointment. If anyone in your home has respiratory or heart conditions, treat no AC as an emergency regardless of temperature. Indoor temperatures above 26°C (79°F) pose health risks for sensitive individuals.
Loud banging or popping could indicate ignition or combustion chamber issues. Grinding or scraping often means broken motor bearings or fan blades destroying themselves. Squealing might be a failing blower motor or loose belt. If you hear sudden, loud, persistent mechanical noises, shut off your system at the thermostat and breaker immediately and call for emergency service. Running a damaged system can cause complete failure and cost thousands more in repairs. A failing motor can also overheat and become a fire hazard.
We typically respond within 60-90 minutes to emergency calls in St. Thomas. For London locations, response time is usually 45-75 minutes depending on traffic and your specific neighbourhood. We prioritize no-heat and gas smell calls above all others. Our technicians carry common parts on their trucks to complete most repairs on the first visit. We communicate ETAs via text message and call when we're 15 minutes out. For surrounding areas like Dorchester, Belmont, and Ilderton, add 15-20 minutes to these estimates.
Don't wait to see a leak. Natural gas is invisible and odorless until the mercaptan additive is added. Evacuate immediately. Do not use any electronics, light switches, phones, or create any spark. A single spark can cause an explosion. From a safe distance (neighbour's house or outside), call Enbridge Gas emergency line at 1-866-763-5427. After they secure the gas supply, call us for furnace inspection and repair. Do not re-enter until both Enbridge and we have cleared your home. This is not a drill — gas leaks can be deadly.
Usually no, but a severely clogged filter can cause the system to overheat and shut down on safety limits. In winter, this can lead to no heat. Check and replace your filter first. If that doesn't restore heat within 30 minutes, call for service. Regular filter changes prevent most of these situations. For safety, never run your furnace without a filter as this allows dust and debris to damage the blower motor and heat exchanger. Set a calendar reminder to check your filter monthly during heating season.
Yes, we serve all of Southwestern Ontario including Dorchester, Belmont, Ilderton, Komoka, Lambeth, Mount Brydges, Strathroy, and even as far as Tillsonburg and Woodstock. Emergency response times vary by distance, but we prioritize these calls alongside London and St. Thomas. Call our 24/7 line at (647) 550-4220 and we'll dispatch the nearest available technician. We don't charge travel fees within our service area. If you're in a surrounding community, you get the same zero-surcharge emergency service as London residents.
24/7 Emergency Service — Zero Surcharge
When you have a true HVAC emergency in London, St. Thomas, or the surrounding area, don't wait. Call the reliable 24-hour team at Hawana HVAC. We answer every call, day or night, with no after-hours premiums.
📞 (647) 550-4220
Call Emergency Line Now Book Online (Non-Emergency)