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Heating · ElectricElectric Furnace Installation
Electric furnace installation makes sense in a house with ducts and no gas main: no gas line, no venting and no combustion, only a cabinet of heating elements and a blower. Houses typically need 10–25 kW, and a 20 kW furnace draws about 83 amps at 240 volts, so the electrical panel decides the job as much as the furnace does. Before you commit, compare it with a cold-climate heat pump on an air handler with electric backup, which delivers the same heat for roughly a third to a half of the electricity over a season.
Electric furnaces are sized in kilowatts, not BTU. One kilowatt is 3,412 BTU per hour and all of it ends up in the air stream, so a 15 kW furnace delivers about 51,000 BTU per hour and a 20 kW unit about 68,000. We size from a heat-loss calculation of the house, not from the old furnace's label, because oil and propane furnaces in farmhouses were routinely oversized. Too many kilowatts costs nothing in efficiency but can cost you a service upgrade you did not need.
The electrical side is where these jobs are won or lost. Element banks are split across two or more 240-volt breakers, the wire is sized to the nameplate, and the furnace needs a means of disconnect at the unit. A 100-amp service usually cannot carry a 20 kW furnace alongside a range, a dryer and an electric water heater, so a load calculation comes first. A 200-amp upgrade involves your utility: Hydro One in rural Caledon and Flamborough, Milton Hydro or Burlington Hydro in town.
The supply circuit is electrical installation work. In Ontario it is done by a Licensed Electrical Contractor who files a notification with the Electrical Safety Authority, and the ESA inspects it. We set the furnace, connect it to the ductwork, set the blower speed and element staging, and coordinate the electrical contractor so the two trades overlap on site. An electric furnace involves no gas piping, no vent and no TSSA work, and nothing in it can produce carbon monoxide.
Here is the honest comparison for homes beyond the gas mains in rural Caledon, Flamborough, Campbellville and the edges of Milton. An electric furnace is the cheapest heating equipment to buy and the most expensive to run: one unit of heat for every unit of electricity, where a cold-climate heat pump moves two to three for most of the winter and keeps electric elements as backup for the coldest nights. A 3-ton cold-climate heat pump installs for $9,500–$15,000, and Ontario's Home Renovation Savings Program currently returns up to $7,500 on qualifying systems. See rebates for electrically heated homes and our electric furnace vs heat pump comparison; on a street with a gas main, gas furnace installation is the third option to price.
An electric furnace on its own is the right call when
- The house is small or very well insulated, so the yearly heating bill is modest whatever heats it
- You are replacing a failed electric furnace and the wiring, breakers and ducts are already in place
- The building is a cottage, shop or addition heated only part of the time
- The budget this year covers the furnace, and you want an air handler that can take a heat pump later
- An oil or propane furnace is being retired and there is no gas main on your road
How it works
We measure the house for heat loss and check the duct system's airflow, since elements trip their limits if the ducts cannot move enough air. The panel, service size and existing circuits are recorded for the electrical load calculation, and the quote shows the electric furnace beside a heat pump option.
The old furnace comes out and the new cabinet is set and sealed to the plenum and return. The Licensed Electrical Contractor runs or reconnects the supply circuits, files the ESA notification and lands the conductors on properly torqued lugs.
We set the element staging so the load comes on in steps, measure amp draw on every stage and the temperature rise across the furnace against its nameplate, and confirm the thermostat controls it properly. You get the readings and the ESA paperwork for your records.
Common questions
How much does electric furnace installation cost?
The furnace itself is the least expensive type of central heating equipment, and the install is simple when wiring exists. The cost drivers are electrical: new supply circuits, a panel or service upgrade, and any duct changes for airflow. Those vary so widely from house to house that we do not publish a figure. The site visit and written quote are free: book a quote.
What size breaker does an electric furnace need?
It depends on the kilowatts. The nameplate lists the minimum circuit ampacity and maximum breaker for each supply circuit, and larger furnaces split the load across two or more breakers. As a guide, every 5 kW of elements draws about 21 amps at 240 volts, before the blower. The electrical contractor sizes breakers and wire to the nameplate and the Ontario Electrical Safety Code, not by rule of thumb.
Will my 100-amp panel handle an electric furnace?
Sometimes, for a small furnace in a house with propane cooking and water heating. Usually not for 15 kW and up in an all-electric house. The answer comes from a load calculation, not from counting empty breaker slots. If an upgrade is needed, a heat pump may change the math, since it draws far less than resistance heat — see panel upgrades for heat pumps.
Can I add a heat pump to an electric furnace later?
Yes, if the cabinet is chosen for it. A modular air handler, or an electric furnace with room for a matched indoor coil, lets a heat pump be added later with the elements becoming backup heat. Tell us at quote time so the cabinet, the plenum height and the thermostat wiring are all set up for heat pump installation down the road.
Is an electric furnace safer than gas?
It removes the combustion risks: no gas leak, no flue and no carbon monoxide from the appliance. Its risks are electrical, mainly loose connections that overheat under a heavy continuous load, which is why lugs are torqued and amp draw is measured at commissioning. If the house has other fuel-burning appliances or an attached garage, Ontario's carbon monoxide alarm rule still applies.