How Many Amps Does an Attic Fan Use?

Attic Fan amperage at 120 V and 240 V

Same 300 W load: the current halves when the voltage doubles. Attic Fan is typically a 120 V appliance in US homes.

The startup surge lasts a fraction of a second; it matters for generator sizing and breaker trip curves, not for your electric bill.

Breaker and circuit for an attic fan

At 2.5 A, an attic fan fits comfortably on a standard 15 A or 20 A household circuit. For a dedicated circuit, guidance is a 15 A breaker with 14 AWG copper (75°C terminations), sized at 125% of the running current because it runs 3+ hours at a time (NEC 210.20).

Guidance only: actual circuit sizing depends on your unit's nameplate, wire run length, and local code. Confirm with a licensed electrician. See the wire & breaker size chart for the full NEC ampacity table.

Measure what an attic fan actually draws

The figures above are typical ratings, and this load is usually hardwired or on a 240 V circuit, so a plug-in meter can't reach it. A clamp meter reads the current on one conductor at the disconnect or panel without breaking the circuit; opening a panel is work for someone qualified, and the voltage pen confirms a circuit is dead first.

We earn a commission if you buy through links on this page, at no extra cost to you. It does not change what we recommend. See our affiliate disclosure. As an Amazon Associate I earn from qualifying purchases.

Clamp meter

Fluke 323

Best for: Measuring what a hardwired circuit actually draws, even in a crowded panel

Check price on Amazon: Fluke 323 (opens in a new tab)(paid link)

Non-contact voltage tester

Klein Tools NCVT-3P

Best for: Confirming a circuit is dead before you open a device or box

Check price on Amazon: Klein Tools NCVT-3P (opens in a new tab)(paid link)

Frequently asked questions

Amp draw of other appliances

• Space Heater13 A
• Window Air Conditioner10 A
• Central Air Conditioner15 A
• Heat Pump13 A