Electric furnace: no heat

Q: Electric furnace: no heat

In Canada, when an electric furnace stops making heat, start with the thermostat — set too low, in a setback, or with dead batteries so it never calls for heat. Next, check whether the furnace breaker has tripped (these draw heavy current on double-pole breakers). A clogged air filter can trip the high-limit and shut the elements off, so check that too. If those are fine, a burned-out heating element or sequencer, or a failed blower motor or control board, may be to blame — that work is on high-current 240-volt circuits and belongs to a licensed electrician or HVAC tech. If you smell burning or a breaker trips again the moment you reset it, stop and call a licensed electrician.

No heat is stressful, but on an electric furnace the first things to check are simple and free — the thermostat, the breaker, and the air filter — long before anything expensive is in play.

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In Canadian homes, check the thermostat first. Make sure it's set to Heat and turned well above room temperature, that it isn't in a programmed setback, and — if it takes batteries — that they're fresh. A thermostat that never calls for heat is the single most common reason an electric furnace goes cold, and it costs nothing to rule out.

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handymanHow to fix it

Find the filter slot at the furnace's return, slide out the old filter, and slide in a clean one of the same size and airflow rating, arrow pointing toward the furnace. Let the furnace cool, then set the thermostat to call for heat and confirm warm air.

Turn the thermostat to Off, then find the filter slot in the return duct or the furnace cabinet.
Slide out the old filter and note the size printed on its cardboard frame and the airflow-arrow direction.
Slide in a clean filter of the same size, arrow pointing toward the furnace, so return air passes through it into the blower.
If the high-limit had locked out, give the furnace time to cool, then set the thermostat to call for heat and confirm warm air. Replace the filter every 1–3 months.

schedule10 min savings$5–25

Furnace air filterMatch the size printed on the old filter's frame (e.g. 16x25x1) and a similar airflow/MERV rating

visibilityHow to check

report This is high-current 240-volt workAn electric furnace's elements run on heavy 240-volt circuits, and more than one may be live even when the furnace looks off — only the breakers truly de-energize it. Turn off every furnace breaker, verify the furnace is dead with a tester before you open it, and keep both hands clear of terminals. If testing a live high-current appliance isn't something you're set up to do safely, this is a straightforward job for a licensed electrician or HVAC tech.

Turn OFF every breaker feeding the furnace and verify the furnace is dead with a voltage tester before removing any access panel — an electric furnace can carry several 240-volt element circuits at once.
With power confirmed off, inspect the elements and sequencers for obvious damage — a broken coil, discoloured terminals, or a scorched sequencer.
Test each element for continuity with a multimeter: a good element reads a low resistance end to end, while an open (no continuity) element is burned out. A sequencer that never closes its contacts on a call for heat is failed.

buildmultimeterbuildscrewdriver schedule30 min

handymanHow to fix it

With every furnace breaker off and verified dead, photograph the wiring, remove the failed heating element or sequencer, and fit a matching replacement rated for the furnace's voltage and wattage — then confirm all terminals are tight before restoring power.

Switch OFF every breaker feeding the furnace and confirm it is dead with a voltage tester at the element terminals before touching any wire.
Photograph the existing connections, then release the wires from the failed element or sequencer.
Fit a replacement matched to the furnace's voltage and element wattage (and the exact sequencer part number), and reconnect each wire to its original terminal, snug and secure.
Reinstall the access panel, restore power, set the thermostat to call for heat, and confirm the furnace warms in stages as the sequencer brings the elements on.

schedule60 min savings$40–120

Electric furnace heating element / sequencerMatch the furnace make and model, the element voltage and wattage, and the exact sequencer part number

gavel Vérifiez d’abord votre province AB: permis au propriétaire · BC: permis au propriétaire · ON: permis et inspection requis · PE: permis au propriétaire · QC: réservé aux licenciés
High-current furnace element/sequencer work is heavier than a like-for-like device swap; confirm the provincial rule and whether a permit or licensed electrician is required.

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Diagnosing a blower motor or control board means working inside a live 240-volt furnace to tell a failed motor from a failed board, then replacing the right part and confirming the heating sequence runs safely. That is HVAC and electrical work, not a homeowner task — leave the furnace off at the breaker and call a licensed HVAC tech or electrician.

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