Posted by The Hot Tub Professor | SpaPartsNet.com
If you’re replacing a spa pump and you’re shopping based on horsepower alone, you’re already being misled.
Let’s clear up one of the biggest myths in the hot tub industry.
The Problem with Horsepower Ratings
Horsepower (HP) printed on a pump motor is often a marketing number — not a true working measurement.
Manufacturers can label motors in ways that make them look more powerful than they actually are.
Amperage tells the real story.
Electricity does not exaggerate.
If you want to know what your pump actually produces, look at the amps on the motor label — not the HP sticker.
How to Find the True Output of Your Pump
Look at the data plate on the motor.
For 230-Volt Hot Tubs
Most full-size portable spas use 230V pumps.
If it’s a two-speed pump, you’ll see something like:
10.0 / 3.5
-
10.0 amps = high speed
-
3.5 amps = low speed
Single-speed pumps will show only one amperage number.
The high-speed amperage is what determines the real working horsepower.
Real-World Amperage to Horsepower Guide
Here’s what those amp numbers usually translate to in actual working HP:
-
8 amps ≈ 1 HP
-
10 amps ≈ 2 HP
-
12 amps ≈ 3 HP
-
14 amps ≈ 4 HP
-
16 amps ≈ 5 HP
These are practical averages used in the field.
Always match the amperage as closely as possible to your existing pump.
Why “More Horsepower” Can Create Big Problems
One of the most common mistakes we see at SpaPartsNet is someone trying to “upgrade” to a higher HP pump.
Bigger is not better.
Higher amperage means higher electrical draw — and your spa was wired for a specific load.
If you increase amperage, you can cause:
-
Burned control boards
-
Melted pump plugs
-
Failed relays
-
Constant breaker trips
-
Heater shutdown issues
-
Premature motor failure
The system is designed as a balance. When you change one part of the equation, everything else feels it.
The Electrical Math Most Owners Overlook
Let’s use real numbers.
If someone claims your spa has two 5 HP pumps:
True 5 HP ≈ 16 amps each
Two pumps = 32 amps
Add a 5.5 kW heater (≈21 amps)
Now you’re at 53 amps total.
Most hot tubs are wired for 50 amps.
That means those pumps are not true 5 HP — no matter what the sticker says.
Electrical math doesn’t lie.
Warning for 115V Plug-and-Play Spas
This is critical.
True 2 HP 115V pumps are extremely rare.
Installing a higher amp pump in a plug-and-play spa can:
-
Melt wiring
-
Damage the plug
-
Destroy the control board
-
Burn up the motor
-
Trip breakers constantly
If your spa plugs into a standard outlet, you must match amperage exactly.
Never upgrade amperage in a 115V system.
Don’t Forget Frame Size
Electrical specs aren’t the only thing that must match.
Motor frame size matters.
Measure across the back of the motor housing:
-
48 Frame → approximately 5 ¾ inches wide
-
56 Frame → approximately 6 ½ inches wide
Frame size affects mounting bolts, wet end alignment, and overall fit.
If frame size doesn’t match, the pump won’t install properly.
Final Advice from The Hot Tub Professor
Ignore marketing horsepower numbers.
Match:
-
Voltage
-
Amperage
-
Speed (single or two-speed)
-
Frame size
-
Plumbing orientation
When in doubt:
Text us clear photos of your pump label.
We’ll confirm the correct replacement before you order.
Getting it right the first time saves you time, money, and frustration.
Contact Our Pump Specialists
Text photos: 772-800-5445
Call: 844-500-4645
Email: dvillanueva@spapartsnet.com
SpaPartsNet.com
Written by The Hot Tub Professor
With over 25 years of hands-on spa repair and diagnostics experience, The Hot Tub Professor focuses on real-world electrical performance — not inflated marketing claims.