Why Horsepower Labels Can Be Misleading

When shopping for a replacement hot tub pump, many people focus on the horsepower (HP) printed on the motor label. Unfortunately, this is one of the most misleading numbers in the spa industry.

Here’s the truth:

Horsepower labels are often inflated. Amperage does not lie.

Pump manufacturers can label motors with almost any horsepower they want, but the electrical amperage tells the real story about how powerful a pump truly is.

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How to Determine Real Pump Horsepower

Instead of trusting the HP printed on the label, look at the amperage (amps) listed on the motor.

For 230-Volt Spa Pumps

(Which is what most full-size hot tubs use)

If you have a two-speed pump, the label will show two numbers, such as:

10.0 / 3.5

• The first number (10.0) is the high-speed amperage

• The second number (3.5) is low speed

If you have a single-speed pump, you’ll see only one amperage number.

Real-World Amperage to Horsepower Chart

Use this chart to determine the true working horsepower of your pump:

• 8.0 amps ≈ 1 HP

• 10.0 amps ≈ 2 HP

• 12.0 amps ≈ 3 HP

• 14.0 amps ≈ 4 HP

• 16.0 amps ≈ 5 HP

Important: These amperage values are averages. Always match the amperage closest to what’s printed on your motor label.

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Why “Upgrading” Horsepower Can Damage Your Spa

Many spa owners try to “upgrade” by installing a pump with higher horsepower or higher amperage.

This is a mistake.

What Happens When You Increase Amperage:

• Control boards overheat

• Relays fail prematurely

• Wiring and plugs melt

• Breakers trip

• Heaters shut down or fail

The Electrical Math Most People Miss

Let’s say you were told your spa has two 5 HP pumps.

Using real numbers:

• Two pumps at 16 amps each = 32 amps

• A 5.5 kW heater draws ~21 amps

• Total draw = 53 amps

Most hot tubs are wired for 50 amps.

? That means you do NOT have two true 5 HP pumps, no matter what the label says.

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Special Warning for 115V (Plug-and-Play) Hot Tubs

• 2 HP 115V pumps are extremely rare

• Installing a higher-amp pump in a plug-and-play spa can:

  • Burn wiring

  • Melt plugs

  • Damage the control board

  • Destroy the pump motor itself

Do not order a higher HP pump for a 115V spa thinking it will add power. It will cause damage.

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How to Identify Your Pump Frame Size

Another critical spec is motor frame size.

Measure the width of the motor across the back:

• 48 Frame → approx. 5 ¾ inches

• 56 Frame → approx. 6 ½ inches

Frame size affects mounting, fitment, and compatibility — it must match your original pump.

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Final Advice from The Hot Tub Professor

Trust amperage, not horsepower. Always match electrical specs.

If you’re unsure:

• Text clear photos of your pump label

• Call to confirm before ordering

• Let us match the pump correctly the first time

Contact Our Pump Experts

? Text photos: 772-800-5445
☎️ Call: 844-500-4645
? Email: dvillanueva@spapartsnet.com

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Written by The Hot Tub Professor

With over 25 years of hands-on experience in spa repair, diagnostics, and real-world troubleshooting, The Hot Tub Professor helps spa owners and technicians avoid costly mistakes by focusing on what actually works — not marketing hype.

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