Electric Heat · Design Guide

Electric Baseboard Heating in Ontario: Sizing Each Room, the SB-12 Package, and the Ventilation Everyone Forgets

Baseboards look like the simple option. No furnace, no ducts, no gas line. Then the permit comes back asking for a heat loss, an energy form for electric heat, and ventilation duct drawings for a house that has no ducts.

Here is what an electric baseboard house actually needs on paper, how to size each room, and why so many owners end up adding a heat pump.

No ducts for heat does not mean no ducts at all. The house still needs ventilation.
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Room-by-room heat loss with baseboard wattage per room, ventilation design and the RMVDS for your permit.
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Sizing Each Room

Every room with a baseboard needs its own number. The room-by-room heat loss gives the heat each room loses on design day, in BTU per hour. One watt is about 3.4 BTU per hour, so the conversion to baseboard wattage is simple.

Rooms with lots of glass, outside corners, or a floor over a garage need more than their size suggests. Size them by the calculation, not by the length of the wall.

Add it up early

Total the baseboard wattage and give it to your electrician before the panel is ordered. A house full of baseboards can push you toward a bigger electrical service.

What the Permit Usually Wants

The Heat Loss

Room by room, at your design temperature, with the baseboard size for each room.

The Energy Form for Electric Heat

SB-12 has separate packages for electric resistance heat, which generally ask more of the envelope. See SB-12.

The Ventilation Design

An HRV or ERV with its ducting, because the house still needs fresh air.

The Ventilation Summary (RMVDS)

The RMVDS showing the ventilation system for the permit.

Schedule 1

Signed by the qualified designer responsible.

Electrical

Baseboard circuits and thermostats are electrical work with their own permit through the ESA.

Baseboards vs a Heat Pump

Install Cost

Baseboards win. Cheap to buy and install.

Running Cost

A heat pump wins. It makes two or three units of heat for each unit of electricity on most winter days.

Comfort

Baseboards are quiet and room-by-room. Heat pumps add cooling.

The Common Answer

Ductless heat pumps for the main spaces, baseboards for the rooms the heads cannot reach and the coldest nights.

Electrically heated homes also get the larger heat pump rebate tier in Ontario. See the rebate guide.

Where Baseboards Make Sense

Small additions, bunkies, basement suites, rooms over garages, and backup for a heat pump. In a tight, well-insulated house with a small heat loss, the running cost gap shrinks too.

For a whole house in a cold part of Ontario, run the numbers on a heat pump before you commit. See switching from electric heat.

Going electric? Send the drawings. We size every room and do the ventilation design and RMVDS for the permit.

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Electric Baseboard Questions
Do electric baseboards need a heat loss for the permit?

Yes. Each room’s baseboard is sized from that room’s heat loss, and the permit wants to see it. One watt is about 3.4 BTU per hour, so the heat loss converts straight into baseboard wattage per room.

My house has no ducts. Why did the building department ask for duct drawings?

Because the house still needs ventilation. A new house with baseboard heat still needs an HRV or ERV and its ducting, shown on the drawings and on the ventilation summary (RMVDS).

Is there a different SB-12 package for electric heat?

Yes. SB-12 has separate compliance packages for houses heated with electric resistance, and they generally ask more of the building envelope. Pick the package that matches your heating. See SB-12 explained.

Are baseboards cheap to run?

Cheap to install, expensive to run. Electric resistance turns one unit of electricity into one unit of heat. A heat pump turns one unit into two or three on most winter days.

Can I combine baseboards with a heat pump?

Yes, and it is a very common setup. Ductless heat pumps do most of the work, and baseboards cover the rooms the heads do not reach and the coldest nights.

Does a house full of baseboards need a bigger electrical service?

Possibly. Add up the wattage from the heat loss and give it to your electrician early. A service upgrade found late is an expensive surprise.

Electric, Done Right
Room-by-Room Wattage and Ventilation

Send your drawings. We calculate each room, give you baseboard wattage, and design the ventilation with the RMVDS for your permit.

  • CSA F280 room-by-room heat loss
  • Baseboard wattage per room
  • Ventilation design and RMVDS
  • BCIN-stamped for the permit
  • From $395, 48-hour delivery
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