Electric Baseboard Heater Not Working? What to Check, and When to Call an Electrician

When an electric baseboard heater won't heat, the cause is usually the thermostat, a tripped breaker, or the heater's built-in overheat cutoff. The cutoff shuts the heater off when furniture, drapes, or dust block its airflow, and Cadet says it resets on its own once the heater cools. Those three are yours to check. Anything inside the heater, the thermostat's wiring, or the circuit is an electrician's job: these heaters run on line voltage, often 240 volts.

This page covers hardwired electric baseboards. A hot-water baseboard, the fin-tube kind fed by a boiler, is a different system: see how to bleed radiators and baseboard. A plug-in “portable baseboard” heater follows the space heater rules further down.

Three Quick Checks

1. Turn the thermostat all the way up. On a dial, Honeywell says to listen for the click and expect the heater to start warming within two minutes. Cadet's electronic built-in thermostat can take up to 5 minutes to start, and it briefly shows “LOC” if its buttons are locked. Then be patient: Cadet says baseboard heaters generally take 30 to 60 minutes to heat a room.
2. Check the breaker. Baseboard heaters have to be on a circuit of their own, shared with no outlets or lights (Cadet), usually a double-pole breaker for a 240-volt heater. Turn that room's thermostats down first, then reset the breaker once: our breaker guide shows how. If it trips again, leave it off and call an electrician.
3. Clear the heater and wait. Move beds, sofas, drapes, bedding, and anything else away from it. If the overheat cutoff tripped, Cadet says it resets after the heater cools, so give it time, then try the thermostat again.

Most Likely Causes

No Heat at All

• The thermostat isn't calling for heat: set too low, locked, or the wrong thermostat. Cadet says a heater's thermostat is either on the wall or on the heater itself.
• A tripped breaker. If it trips again as the heater comes on, Stelpro points to a supply voltage higher than the heater's rating or a defective element. Both are an electrician's job.
• The overheat cutoff. If something blocks the heater, it shuts off and stays off until it cools (Cadet, Marley).
• A failed thermostat or loose wiring. If the heater doesn't warm within two minutes with the dial all the way up and the breaker on, Honeywell says to have an electrician check the thermostat and heater.
• Every heater in the house is out. That points to the panel or the power coming in; see half the house has no power.

Heats for a While, Then Stops

That's the overheat cutoff cycling. Dimplex says restricted airflow can make it cycle the heater on and off, so it can't supply enough heat to the room. Clear the heater and clean it (below). If the cutoff keeps tripping with nothing in the way, Marley says to disconnect the power and have the heater checked by a qualified electrician, and Stelpro says the same for protection that activates repeatedly.

Runs, but the Room Never Gets Warm

• Dust on the fins. Dimplex says a heater shouldn't run with dust or dirt built up on the element, which can trap heat and damage it, and University of Missouri Extension says dust on baseboard units acts as insulation and wastes heat.
• A heater too small for the room. Cadet and Stelpro both list heat loss greater than the heater's capacity. Close doors and windows; adding insulation helps, and a bigger heater or a second one is an electrician's job because the circuit may be limited (Cadet). See one room colder than the rest for drafts and insulation.
• The wrong voltage after a new install. Cadet says a 240-volt heater wired to a 120-volt circuit gets only 25% of its rated wattage. Compare the voltage on the heater's label with the breaker: Cadet's diagram pairs a single-pole breaker with 120 volts and a double-pole breaker with 240. Testing and rewiring are an electrician's job.
• A thermostat in a warm spot. Sun or another heat source makes it shut off early. Cadet says a thermostat right above the heater picks up its leftover heat. Moving a wall thermostat is an electrician's job; Honeywell puts it about 5 feet up on an inside wall.

Won't Turn Off

• A single-pole thermostat. Marley says single-line-break thermostats have no OFF position and keep running below their lowest setting. Cadet's fix is a double-pole thermostat with a true off, installed by an electrician.
• A failed thermostat. Honeywell's test: turn the dial fully down, and the heater should start to cool within minutes. If it doesn't, turn off the power at the panel and call an electrician.
• A heater too small for the room runs nonstop trying to keep up (Cadet, Stelpro).

Only One Room Is Cold

Each room has its own heater and thermostat, Cadet says, so check that room's thermostat, its breaker, and whether something is blocking its heater. If only one of several heaters on the same thermostat is cold, that heater's cutoff or wiring is the likely problem, and that's an electrician's call.

What You Can Fix Yourself

Clean It

Cadet says to clean the heater at least every 24 months, or as needed; Stelpro says once a year. Switch the breaker off and make sure the heater is cool. Vacuum the fins with a brush attachment without touching the element (Cadet), and go gently: Marley warns the fins are sharp and can cut. Marley's manual allows basic cleaning by the owner and leaves all other servicing to qualified service personnel, so leave the wiring compartments closed.

Give It Room

Keep anything that can burn well away. NFPA's rule for heating equipment is at least 3 feet, and Cadet's own rule of thumb for its heaters is 3 feet in front. The manuals' minimum clearances are much smaller and vary by maker; they're the least each one allows, not a target:

Drapes must never touch a heater; Stelpro keeps them at least 6 inches away. Don't enclose a heater or set it into the wall (Marley), and keep electrical cords away from it (Marley). Cadet, Stelpro, and Dimplex all say not to install a heater below an electrical outlet.

Set It Right When You're Away

Baseboard thermostats can go as low as 40°F (Honeywell), and double-pole models switch fully off. In cold weather, don't leave them off or at the lowest setting while you're away: keep the heat no lower than 55°F, the American Red Cross minimum, so the pipes don't freeze. See thermostat settings when you're away.

What Not to Do

• Don't bypass the overheat cutoff, even to test it. Marley says doing so could make the heater a fire hazard, and Cadet, Stelpro, and Dimplex forbid tampering with it too.
• Don't replace the thermostat, tighten connections, or open the wiring compartments yourself. Honeywell warns that its line-voltage thermostats carry 120 to 240 volts and a risk of electric shock that may cause serious injury or death; it says not to install one unless you're completely familiar with house wiring. Our thermostat guide sends this to an electrician.
• Don't keep using a thermostat that has malfunctioned. Cadet says to turn off the power at the panel and have an electrician inspect it first.

Plug-In “Portable Baseboard” Heaters

A baseboard-style heater with a cord is a portable heater, and the space heater rules apply: keep it 3 feet from anything that can burn, plug it straight into a wall outlet, and turn it off and unplug it when you leave the room or go to sleep (CPSC, NFPA). Cadet's and Marley's plug-in models say never to use an extension cord, and Cadet adds never a power strip. Their manuals allow 12 inches of clearance; the 3 feet is stricter, so use it. See our space heater safety rules.

When to Call an Electrician

• The breaker trips again after one reset, or won't reset.
• No heat with the breaker on and the thermostat all the way up (Honeywell).
• The heater won't turn off at the lowest setting; turn off its breaker first (Honeywell).
• The overheat cutoff keeps cycling the heater with nothing blocking it (Marley, Stelpro).
• The heater glows red, or keeps getting unusually hot and shutting off; switch off the breaker first (Cadet).
• A thermostat needs replacing or moving, or has malfunctioned (Honeywell, Cadet).
• Any wiring work, a new heater that doesn't heat, or a voltage that needs testing. Cadet says testing with a voltmeter means keeping the power on, so leave it to a licensed electrician.
• Your home has aluminum branch wiring, which needs special connectors at the thermostat (Honeywell); see aluminum wiring.

While you wait, a portable electric space heater can keep one room warm if you follow the rules above, and the pipe freeze check shows whether tonight is cold enough to worry about the pipes.

Frequently Asked Questions

Does a baseboard heater have a reset button?

Not on the baseboard models we checked. Cadet says its overheat cutoff automatically resets after the heater cools, and Marley's turns the heater off and back on by itself. Clear anything blocking the heater and give it time. If it keeps shutting off, switch off the breaker and call an electrician (Marley).

Why won't my baseboard heater turn off, even on the lowest setting?

A single-pole thermostat has no off position, Marley and Cadet say, and keeps heating below its lowest setting. If the room is already warm and turning the dial fully down doesn't stop the heater within minutes, Honeywell says to turn off the power at the panel and call an electrician.

Why does my baseboard heater smell like burning?

The first time a new heater runs, Cadet says a burning odor is normal and comes from a protective lubricant used in manufacturing; it usually fades within several hours. A smell that doesn't fade, or a heater that glows red, means switch off its breaker and call an electrician (Cadet).

How far should furniture and curtains be from a baseboard heater?

The makers' minimums run from 3 to 12 inches in front (Stelpro, Dimplex, Marley, Cadet), and drapes must never touch the heater. NFPA's general rule is to keep anything that can burn at least 3 feet from heating equipment, and Cadet's rule of thumb is 3 feet in front.

Can I replace a baseboard heater thermostat myself?

We say hire an electrician. Honeywell warns that its line-voltage thermostats carry 120 to 240 volts and a risk of serious shock, and not to install one unless you're completely familiar with house wiring.

How long should a baseboard heater take to warm a room?

Cadet says 30 to 60 minutes. The heater itself should start warming within about two minutes of turning the dial up (Honeywell).

The Bottom Line

Turn the thermostat all the way up, reset the breaker once with the thermostats down, and clear and clean the heater with the power off. A baseboard heater's overheat cutoff resets itself, so don't look for a button, and never bypass it. A breaker that trips again, a heater that won't turn off, a cutoff that keeps tripping, or anything involving the wiring or thermostat is a job for a licensed electrician.

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