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G-016 · REV 2 · CHECKED 2026-10-09 · MODEL v1.0.2 ▾

Drafted with AI assistance. Numbers computed by model v1.0.2 or sourced. Human review: pending (BayHeat editorial desk). Licensed review: no page-specific approval recorded.

Technical review: no page-specific licensed approval recorded.

M measured · C computed · S spec · R reference · E estimate

240V garage heaters

A 5,000W 240V heater needs a breaker and 10 AWG copper. A 4,000W heater draws less current but still needs a circuit — it does not fit the 20A circuit already run to most garages. Bigger units scale the same way: 7,500W needs and 8 AWG, 10,000W needs and 4 AWG NM.

Model pick · spec-based

Comfort Zone CZ220 5,000W ceiling heater5.0 kW · 240 V / 30 A

Start here: 5 kW on its own 240 V / 30 A circuit

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Check price on Amazon
Paid linkSee the breaker and wire for every size ↓

Manual: not where gasoline, paint or flammable liquids are used or stored. Indoors only, in a dry space free of combustible dust. Source ↗

Paid links: we earn a commission if you buy through links on this page, at no cost to you. As an Amazon Associate, BayHeat earns from qualifying purchases.

The breaker and wire, for every common size

A 240V heater is a fixed appliance, not a plug-in — treats it as a continuous load, so the breaker and wire are sized at 125% of the actual running current, not the nameplate amps alone. That 25% margin is why the numbers below don't line up with wattage the way you'd guess.

HeaterRunning currentBreakerWire (NM/Romex)
4,000W10 AWG
5,000W10 AWG
7,500W8 AWG
10,000W4 AWG
The jump from 4,000W to 5,000W looks small on the box. On the panel it isn't — 4,000W still clears a 20A breaker's continuous rating, so it needs its own circuit, same as the 5,000W unit one size up. Neither one runs on the 20A circuit already in most garages.

GFCI: when it applies and when it doesn't

covers receptacles — outlets you plug something into. A hardwired 240V heater has no plug, so this rule doesn't attach to the heater itself. It still governs any 125–250V receptacle elsewhere in the garage, so an electrician wiring a new circuit for the heater will usually address both in the same visit. Your electrician and your local code edition govern.

Adding a large 240V circuit to an existing panel can also trigger — worth asking your electrician about before they open the panel, not after.

Shop for the size your circuit can carry

Price is a range class here, never a live number — check the actual price on the retailer's page before you buy.

240V · 5,000W · 30A

Comfort Zone CZ220 / Fahrenheat FUH54

on a .

Manual: not where gasoline, paint or flammable liquids are used or stored. Indoors only, in a dry space free of combustible dust.

Check CZ220 price on Amazonor the FUH54 ↗

Price class: $$ / $$$

240V · 7,500W · 40A

Dr. Infrared DR-975

on a .

Manual: “WARNING – RISK OF FIRE, DO NOT USE AS A RESIDENTIAL OR HOUSEHOLD HEATER.” Also not where gasoline, paint or flammable liquids are used or stored. Ask Dr. Infrared whether your garage counts as residential before you buy.

Check price on Amazon

Price class: $$$

240V · 4,000W · 25A

240V 4,000W hardwired heater

No verified nameplate on file for a specific model yet — the 25A/10 AWG figures above come from at the class's 4,000W rating, not a manual.

Manual: not where gasoline, paint or flammable liquids are used or stored.

Search on Amazon

Price class: $$

240V · 10,000W · 60A

Dr. Infrared DR-910F 10,000W 240V hardwired shop heater

The largest class on this page. and 4 AWG NM is enough panel capacity to think through before you buy — see .

Manual: “WARNING – RISK OF FIRE, DO NOT USE AS A RESIDENTIAL OR HOUSEHOLD HEATER.” Also not where gasoline, paint or flammable liquids are used or stored. Ask Dr. Infrared whether your garage counts as residential before you buy.

Check price on Amazon

Price class: $$$

  • Why not a 120V portable utility heater (1,500W)? A 1,500W plug-in heater tops out around 5,100 BTU/h — a real garage on a cold design day usually needs several times that. It's a workbench heater, not a whole-garage one, no matter how many outlets you spread it across.

See the garage heater calculator for the exact load your garage needs before picking a class. Then see where 240V fits on the best garage heater page. Heating a workshop? The shop heater guide sets a 240V unit beside vented gas and diesel.

Safety

A hardwired 240V heater is a fixed continuous load (), sized at 125% of its running current — that's where every breaker and wire figure on this page comes from. It isn't a receptacle, so the GFCI rule () governs the garage's outlets, not the heater. Your electrician and your local code edition govern.

General information. Your electrician, gas fitter, local code and the heater's manual govern.

Related

Sources

  1. [1] NFPA 70, National Electrical Code, 2023, NFPA. Retrieved 2026-09-25.
  2. [2] Comfort Zone CZ220 Series ceiling mounted heater owner's manual, Comfort Zone (Lowe's copy). Retrieved 2026-10-09.
  3. [3] Fahrenheat FUH54 / FUH54C installation, operation and maintenance instructions (5200-11195-000), Marley Engineered Products. Retrieved 2026-10-09.
  4. [4] Dr. Infrared Heater DR-975 owner's manual, Dr. Infrared Heater. Retrieved 2026-09-30.
  5. [5] Dr. Infrared Heater DR-910F 10,000W 240V wall/ceiling garage heater owner's manual, Dr. Infrared Heater. Retrieved 2026-09-30.
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