🔌 Let’s Talk About Amps, Volts, and Kilowatts
Look, I get it—amps, volts, kilowatts—it can all feel like electrician mumbo jumbo. But when you’re installing a PTAC unit with electric heat, like this Amana Distinctions 14,700 BTU with a 3.5 kW heater, you’ve got to know how much power it pulls.
Otherwise? You could be tripping breakers every time the heat kicks on—or worse, overloading a circuit.
🧮 The Basic Formula
To figure out how many amps your unit draws, use this simple formula:
Amps = Kilowatts Ă— 1000 Ă· Voltage
So for a 3.5 kW heater:
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On a 208V circuit →
3.5 Ă— 1000 Ă· 208 = ~16.8 amps -
On a 230V circuit →
3.5 Ă— 1000 Ă· 230 = ~15.2 amps
That’s just for the electric heat—you also have to factor in the rest of the PTAC’s draw (fan motor, compressor, control board), which might add another 2–4 amps.
So total, you’re looking at about:
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~20–22 amps of draw when the heater is running full blast
⚠️ What Size Circuit Do You Need?
Here’s my rule of thumb:
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For a 3.5 kW PTAC on 208/230V, I always recommend:
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A 30 amp breaker
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With 10-gauge wire
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On a dedicated circuit (nothing else plugged in)
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Never try to share that circuit with a fridge, TV, or microwave. That’s just asking for problems.
🧰 Tony’s Field Tip: Look at the MCA and MOCP
Check the unit’s nameplate (usually behind the front grille) for two key specs:
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MCA = Minimum Circuit Ampacity
This is how much current the unit must have access to -
MOCP = Maximum Overcurrent Protection
This tells you the biggest breaker size you can use safely
For example, this Amana PTAC might say:
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MCA: 18.5A
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MOCP: 30A
That means your breaker should be 25–30 amps, and your wiring should be up to code.
🏠Can You Use This at Home?
Yes—but only if your panel has space for a dedicated 30A 2-pole breaker. Many homes are wired for 15A or 20A circuits, which won’t cut it for a 3.5 kW PTAC.
If you’re not sure, don’t guess—call a licensed electrician or HVAC tech. It’s not worth burning out your breaker box or risking a fire.
🔥 Why This Matters
A lot of people buy a PTAC and then call me saying,
“Tony, why does my unit shut off when it gets cold?”
Turns out, the electric heat kicks in, draws more power, and trips a weak or undersized breaker.
The fix? Upgrade the breaker and wire to match the unit’s draw—or buy a model with lower kW heat, like a 2.5 kW or 2.0 kW kit that draws less juice.
🧯 Safety First
Never:
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Use a cheater plug or adapter to run a PTAC on a 15A outlet
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Install a PTAC without proper wire size
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Ignore a breaker that trips repeatedly
If you’re unsure, have the unit hardwired by a pro. PTACs are meant to be permanently installed, not plugged into a bedroom wall socket.
đź”— Helpful Resources
✅ Tony’s Final Word
A 3.5 kW heat kit brings serious heat—but it also brings serious power demands. Get your breaker and wiring right the first time, and your PTAC will run strong all winter long.
Bottom line: If your panel can’t handle it, don’t install it. Safety and performance go hand in hand.
In the Next topic you will read about: Heat Pump vs Electric Heat in a PTAC: Which One Does the Work?
