PTAC Amperage: How Many Amps Does Your Unit Pull? Tony Breaks Down What Matters

If you’ve ever stood in front of a row of PTAC units and wondered which one fits your space, you probably focused on BTUs. Maybe voltage. But there’s another number on that label you can’t ignore: amperage.

Hey, I’m Tony the Trusted Tech—and today, I’m walking you through what PTAC amp draw really means, how to read it, and why it matters more than you think when it comes to breaker sizing, heater compatibility, and safety.

---

What Does Amperage Mean on a PTAC Unit?

In basic terms, amperage (amps) is the amount of electrical current your unit pulls when it’s operating. For PTACs like the Amana Distinctions 12,000 BTU PTAC with 3.5kW electric heat, that number is tied directly to:

• The power cord it ships with

• The wattage of the electric heat kit

• The breaker size required

• Whether your building circuit can handle the load

It’s not optional—it’s code.

👉 For the basics of how amps relate to HVAC electrical systems, check out this energy.gov HVAC sizing guide.

---

Common Amperage Options for PTAC Units

Most PTACs in the U.S. come pre-configured with one of the following amperage setups:

The cord type and amperage must match your building's outlet and breaker. No exceptions.

For example:

• A 15A unit plugged into a 30A circuit = code violation

• A 30A unit on a 20A breaker = trips constantly or risks fire

👉 Leviton’s NEMA plug guide is a handy visual to ID your cord type and plug shape.

---

How to Find Your PTAC’s Amperage

1. Check the Model Number
   Most PTAC model numbers end in a letter that tells you the amperage:

• A = 15A

• B = 20A

• C = 30A

For example:
PTH123G35B = 20A unit
PTH123G35C = 30A unit

2. Look at the Nameplate Label
   Pull off the front cover. There will be a silver label near the fan or compressor that lists:

• Voltage

• Heater size (kW)

• Cooling and heating amps

• Circuit ampacity

3. Use a Clamp Meter (Safely!)
   For installed units, a clamp meter on the wire can show live current draw. This is something I do during diagnostics—but make sure it’s done safely with power-on procedures.

---

Why Amperage Matters for Heater Size

A PTAC with higher amperage isn’t “better,” but it can support more electric heat.

Here’s how amperage ties to electric heat output:

• 15A = 2.5kW

• 20A = 3.5kW

• 30A = 5.0kW

If your PTAC is in a northern climate, you’ll probably want the 30A/5kW version to avoid relying too much on backup heat. In southern climates, 2.5–3.5kW is usually enough.

👉 The AHRI’s heat pump standards help explain performance at low ambient temps if you want to get nerdy about it.

---

What Breaker Size Does My PTAC Need?

PTAC units must have dedicated breakers sized to match their amp rating.

You cannot “upgrade” the heater or cord without updating the breaker and wiring, too. Everything has to match.

👉 This NEC code guide summary from ECM magazine explains why overfusing is dangerous—and illegal.

---

Can I Replace My PTAC With a Different Amp Version?

Yes, but only if you upgrade the electrical circuit.

Let’s say you have a 15A PTAC but want a 5kW heater. You’d need to:

• Replace the cord and plug

• Install 10-gauge wire

• Swap the breaker to 30A

• Make sure your outlet matches a NEMA 6-30

That’s not a “swap and go” job—it requires a licensed electrician and probably a permit.

---

Tony’s Final Word

Don’t ignore the amps when buying a PTAC. It’s not just a technical detail—it determines how your unit connects, how much heat it provides, and how safe your install is.

If you’re replacing an old unit, match the amperage exactly unless you’re also updating your circuit. If you’re setting up new construction, work backward from the room size and heat load to pick the right amp draw.

And please—don’t cut off the plug and try to rig something up. I’ve seen that movie, and it ends with melted wires and a call to the fire department.

---

Coming up next in the series: “How to Maintain a PTAC Unit: Filters, Coils, and Drain Pans”