When an ice storm knocks out power in January, the houses that stay warm and lit are the ones with a plan. A propane-fuelled generator can keep your furnace, fridge, and a few lights running for days — without the fuel-going-stale problems of gasoline. For many Canadian homes, it is the most practical winter backup there is.
This guide explains how to size a unit, where to put it safely, how long a tank of propane actually lasts, and the carbon monoxide rules that keep your family safe. Real numbers, no sales pitch.
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Table of Contents
- 1. Why Propane Suits Canadian Winters
- 2. Sizing: Doing the Watts Math
- 3. Portable vs Standby Units
- 4. Dual-Fuel Flexibility
- 5. Carbon Monoxide: Placement Rules
- 6. Transfer Switches Explained
- 7. Fuel Math: How Long a Tank Lasts
- 8. Cold-Weather Starting
- 9. Maintenance That Prevents Failures
- 10. What Not to Power
1. Why Propane Suits Canadian Winters
Propane has three big advantages over gasoline for backup power. It never goes stale — a tank can sit for years and still burn cleanly, while gasoline gums up carburettors in months. It burns cleaner, producing less carbon monoxide per unit of energy. And in most of Canada, propane delivery and refill infrastructure is well established, even in rural areas.
The trade-off is energy density: propane contains about 10 percent less energy per litre than gasoline, so a propane unit burns slightly more fuel for the same watts. Propane tanks also lose pressure in extreme cold — below -30°C, a small 9 kg tank may struggle, which is why larger tanks or tank warmers matter in the Prairies. For most southern Canadian winters, though, propane is the set-and-forget choice.
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2. Sizing: Doing the Watts Math
Generators are sized in watts, and the math is simpler than it looks. List what you must run: a gas furnace fan (800 W running, 2,000 W starting surge), fridge (200 W running, 1,200 W surge), a few LED lights (60 W), phone chargers (50 W), and maybe a sump pump (1,000 W running, 2,000 W surge). Add the running watts, then make sure the generator's surge rating covers your biggest starting load.
For most homes, 7,500 running watts covers the essentials comfortably, including the furnace. A 3,500 W portable handles fridge, lights, and electronics but not electric heat. Electric furnaces, stoves, and dryers are power hogs — a 5 kW electric heater alone needs a 7,500 W unit. When in doubt, size up one step; running a generator at 50 to 70 percent load is more efficient and quieter than maxing it out. Our winter heating guide pairs well with this planning.
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3. Portable vs Standby Units
Portable generators ($800 to $2,500 for propane-capable models) are the affordable entry point. You wheel them out, connect what you need via extension cords or a transfer switch, and refuel from 9 kg barbecue tanks. They are noisy — 70 decibels is typical — and someone must be home to start them.
Standby units ($6,000 to $15,000 installed) are permanently mounted, wired into your panel, and start automatically within seconds of an outage — even if you are away. They run from a large propane tank or natural gas line and are much quieter. If you have a sump pump, work from home, or travel in winter, the automatic start alone justifies the cost. Get quotes from at least three licensed electricians; installation quality matters as much as the unit.
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4. Dual-Fuel Flexibility
Dual-fuel generators run on propane or gasoline with the flip of a switch, and they are worth considering. Use propane as your primary — it stores forever and burns clean — but keep the gasoline option for extended outages where propane delivery might be delayed. In a week-long ice storm, fuel flexibility is genuine resilience.
Expect to pay $100 to $300 more than a propane-only model of the same wattage. The gasoline side needs the usual care: stabilized fuel, run dry before storage, carburettor drained. Many owners never touch the gasoline side — and that is fine. It is insurance, not a daily driver. Just test it once a year so you know it works.
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5. Carbon Monoxide: Placement Rules
This is the life-and-death section. Generator exhaust contains carbon monoxide, an odourless killer. Every year Canadians die running generators in garages, basements, or too close to windows. The rules are absolute: outdoors only, at least 6 metres from any door, window, or vent, with the exhaust pointed away from the house.
Never run one in an attached garage, even with the door open — CO seeps through walls and doors faster than you expect. Install battery CO detectors on every floor and test them monthly; they are $30 to $50 each and non-negotiable if you own a generator. If a detector alarms, get everyone outside immediately and call 911. This pairs with winterizing your home as essential cold-season safety.
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6. Transfer Switches Explained
A transfer switch is the safe, legal way to connect a generator to your home's wiring. It isolates your house from the grid so your generator cannot backfeed power onto dead lines — which can electrocute utility workers. Manual switches ($400 to $800 installed) let you choose circuits; automatic ones come with standby units.
The alternative — extension cords run to individual appliances — is fine for small portables but gets messy fast. What you must never do is plug a generator into a wall outlet with a double-ended cord ("suicide cord"). It is illegal, it bypasses every safety device in your panel, and it kills people. A licensed electrician installs a transfer switch in half a day.
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7. Fuel Math: How Long a Tank Lasts
Here is the practical math. A 7,500 W generator at half load burns roughly 1.5 to 2 litres of propane per hour. A 9 kg barbecue tank holds about 17 litres, so one tank gives you 8 to 11 hours. For a 24-hour outage you need three tanks; for three days, eight or nine.
That is why serious backup means a large tank: a 500-litre tank (filled to 400 litres) runs that same generator for 8 to 10 days at half load. Refills cost $1.20 to $1.80 per litre in most provinces, so a full 400-litre fill is $500 to $700 — expensive, but it buys over a week of heat and light. Keep tanks at least 3 metres from the generator and any ignition source, per code.
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8. Cold-Weather Starting
Generators hate extreme cold as much as cars do. Below -20°C, engine oil thickens, batteries weaken, and propane pressure drops. Use 5W-30 synthetic oil rated for winter, keep the battery on a trickle charger, and consider a battery warmer pad ($40) if your unit lives in an unheated shed.
For propane specifically, keep tanks as full as possible — a full tank maintains pressure better than a nearly empty one — and in Prairie cold consider a larger tank, since surface area affects vaporization. Standby units often include cold-weather kits with block heaters that cycle automatically. Test-start your generator monthly year-round; the one that will not start in January is the one you last ran in July. Cold starts also matter for keeping the garage workable in deep winter.
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9. Maintenance That Prevents Failures
A generator that sits for 11 months must work on demand in month 12. The routine is simple: run it under load for 20 minutes monthly, change the oil after the first 25 hours then every 100 hours or annually, replace the air filter yearly, and check the spark plug each fall. Total annual cost is under $50 in parts.
For propane units, also inspect hoses and regulators yearly for cracks — propane degrades rubber over time. Keep a spare air filter, spark plug, and a litre of oil with the unit so a mid-outage problem does not become a crisis. Log every run and service date on a card taped inside the cover; future you will be grateful.
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10. What Not to Power
Knowing what to leave off matters as much as sizing. Skip electric space heaters, clothes dryers, electric stoves, and central air — each can eat half your generator's capacity alone. Run the furnace fan (not electric heat strips), the fridge, lights, well pump or sump pump, and electronics. Everything else waits.
Be especially careful with sensitive electronics: cheap generators produce "dirty" power with voltage swings that can damage computers and modern furnace boards. Look for inverter generators or units with less than 5 percent total harmonic distortion if you power electronics directly. A $150 UPS between the generator and your computer is cheap insurance. And seal the envelope too — draft-proofing windows cuts the heating load your generator must support.
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FAQs
How much does a propane generator cost in Canada?
Portable propane or dual-fuel units run $800 to $2,500. Installed standby systems cost $6,000 to $15,000 depending on wattage and electrical work. Budget $500 to $700 to fill a 500-litre propane tank.
Can I run a generator in my garage with the door open?
No — never. Carbon monoxide builds to lethal levels even with the door open and seeps into the house. Generators go outdoors, at least 6 metres from doors and windows.
Will propane work at -30°C?
Small tanks struggle as pressure drops in extreme cold. Larger tanks vaporize better, and keeping tanks full helps. For Prairie winters, discuss cold-weather kits and tank sizing with your supplier.
Do I need a permit to install a standby generator?
Usually yes — an electrical permit for the transfer switch and possibly a gas permit for the propane line. Your electrician typically handles permits as part of the installation.
How loud are propane generators?
Portables run 68 to 75 decibels — about as loud as a vacuum. Standby units are quieter at 60 to 65 decibels. Check local noise bylaws, especially for nighttime running.
Final Thoughts
A propane generator is not about comfort so much as control — the ability to keep your home warm, your food safe, and your family calm when the grid goes down. Size it honestly, place it safely, maintain it yearly, and it will sit quietly for years until the night you need it most. In a Canadian winter, that is worth every dollar.
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Photo: Wikimedia Commons
Photo: Wikimedia Commons
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