Space Heater vs Furnace: Which Is Cheaper and Safer to Run?
Space Heater vs Furnace: Which Is Cheaper and Safer to Run?
Ben Amina
Aire One East Heating & Cooling, 1910 Dundas St E #117, Whitby
Space heater vs furnace is a question many Durham Region homeowners ask when the first cold snap hits or the energy bill arrives. A portable electric heater seems cheap to buy and easy to use, and turning down the thermostat while you heat one room sounds like a smart way to save. Sometimes it is. Often it is not, because electric heat usually costs more per unit of heat than a natural gas furnace, and space heaters bring real fire risks. This guide compares a space heater vs furnace on cost, comfort, and safety, explains when a space heater makes sense, shows you how to use one safely, and explains what it means if you rely on space heaters every winter.
- Most Durham homes heat with a natural gas furnace, which usually delivers heat more cheaply than electric space heaters.
- A space heater can save money when you heat one small room for a short time and turn the furnace down, but not when it runs for hours in several rooms.
- Space heaters are a leading cause of home heating fires. Keep them 1 metre from anything that can burn and plug them directly into the wall.
- Never use a fuel burning camp or patio heater indoors because of carbon monoxide.
- If you need space heaters every winter, the real problem is usually your furnace, ducts, or insulation.
Short answer: In the space heater vs furnace comparison, the furnace is usually cheaper for heating your whole home, because natural gas heat typically costs less than electric heat. A space heater only makes sense for warming one small room for a short time while the rest of the house is turned down, and it must be used carefully.
If a cold room has you reaching for a space heater, Aire One East can find out why. Call 905-576-7600.
Space heater vs furnace: which is cheaper to run?
An electric space heater turns almost all of the electricity it uses into heat in the room. That sounds efficient, but the price of the energy matters as much as the efficiency. In most Ontario homes with natural gas service, a unit of heat from a gas furnace costs less than the same heat from electricity. A modern high efficiency furnace also turns most of its fuel into heat for your home.
That is why the space heater vs furnace math usually favours the furnace for heating a whole house. To compare for your own home, look at your Enbridge Gas bill and your electricity bill, or ask us to walk you through it. If your home heats with electric baseboards instead of gas, the comparison changes, and a heat pump is often the better upgrade. Our gas vs electric furnace guide explains the difference.
When a space heater makes sense in the space heater vs furnace choice
- One room, short time: warming a home office for a few hours while the rest of the house is set a few degrees cooler.
- A temporary fix: keeping a room comfortable for a day or two while you wait for a furnace repair.
- A space with no heat: a workshop or seasonal room that is not connected to the ducts, used occasionally.
On the other side of the space heater vs furnace question, a space heater usually does not make sense when it runs for many hours a day, when you use several at once, or when you leave the furnace set at the same temperature. In those cases you are paying for both. Turning the furnace down too far can also leave other rooms cold enough to cause condensation or, in extreme cold, frozen pipes on outside walls.
Space heater vs furnace for comfort
A furnace heats every room through the ducts, filters the air, and can work with a humidifier, so the whole house stays even. A space heater heats only the area around it. You may feel warm in your chair while the rest of the room and the rest of the house stay cold. In the space heater vs furnace comparison, the furnace wins on whole home comfort, while a space heater wins only for quick, spot heating. If one room is always colder than the others, our uneven heating guide explains common fixes, and our HVAC zoning guide explains how to control different floors separately.
Space heater safety tips
- Keep it 1 metre (3 feet) away from curtains, bedding, furniture, paper, and anything else that can burn.
- Plug it directly into a wall outlet. Do not use an extension cord or power bar, and do not run the cord under a rug.
- Look for a certification mark from an accredited body such as CSA or cUL, plus automatic tip over and overheat shut off.
- Never leave it running when you leave the room or go to sleep, and keep children and pets away from it.
- Place it on a hard, level floor, not on a rug, table, or chair.
- Never use fuel burning heaters indoors, such as propane patio heaters, camp heaters, or barbecues. They produce carbon monoxide.
- Test your smoke and CO alarms every month during the heating season.
What it means if you rely on space heaters
If you plug in space heaters every winter, the space heater vs furnace question is really a sign that something in your heating system is not keeping up. Common causes include a furnace that is too small or failing, a dirty filter, a weak blower, leaky or poorly designed ducts, closed or blocked vents, and poor insulation in a room over a garage or an addition. A furnace that short cycles or blows cool air can also leave rooms cold. Our furnace blowing cold air guide and furnace short cycling guide cover those problems.
Fixing the cause usually settles the space heater vs furnace question for good, and it costs less over time than running space heaters for years. If your furnace is old and struggling, our repair or replace guide can help you decide, and for a room addition or finished attic, a ductless mini split heat pump is often the most efficient way to add heat.
How to choose between a space heater vs furnace this winter
- Use the furnace for whole home heat. Set a sensible temperature and use a program. Our winter thermostat settings guide has tips.
- Use a space heater only for short, spot heating in an occupied room, following the safety rules above.
- Fix cold rooms at the source by checking the filter, vents, and ducts.
- Book a furnace tune up so the system runs at its best all season.
Our technicians handle furnace repairs 24/7 across Durham Region, and our maintenance and protection plans keep your furnace tuned every year.
Key terms in this article
- Space heater: a portable heater that warms one room or area
- Electric resistance heat: heat made by running electricity through a heating element
- AFUE: Annual Fuel Utilization Efficiency, the share of furnace fuel that becomes heat
- Zone heating: heating only the rooms in use and lowering the temperature elsewhere
- Tip over switch: a safety switch that turns a space heater off if it falls over
- Certification mark: a label such as CSA or cUL showing a product meets Canadian safety standards
Frequently asked questions
| Your space heater vs furnace questions, answered |
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| Is it cheaper to run a space heater or the furnace? In a space heater vs furnace cost comparison for a whole home, a natural gas furnace is usually cheaper, because gas heat typically costs less per unit than electric heat in Ontario. A space heater can save money only when it warms one small room for a short time while the furnace is turned down. |
| Can I use a space heater instead of my furnace? Not as your main heat. In the space heater vs furnace choice, a space heater warms one area, does not filter air, and can leave the rest of the house cold enough for condensation or frozen pipes. Use the furnace for the whole home and a space heater only for spot heating. |
| Are space heaters safe? They can be used safely if you keep them 1 metre from anything that can burn, plug them directly into a wall outlet, choose a certified model with tip over and overheat shut off, and never leave them running unattended or while you sleep. |
| Why do I need a space heater in one room? Usually because of a duct, vent, insulation, or furnace problem. Common causes include a dirty filter, closed or blocked vents, leaky ducts, a weak blower, or a furnace that is undersized or failing. A technician can find the cause. |
| Is a space heater cheaper than a heat pump? No. A heat pump moves heat instead of making it with resistance, so it delivers more heat per unit of electricity than a space heater. For a cold room or addition, a ductless heat pump is usually the more efficient long term fix. |
Do not take our word for it alone. Read our 364 verified reviews on Google, and see the Heating, Refrigeration and Air Conditioning Institute of Canada for what accredited contractors are expected to deliver.
References and further reading
