AS ColdPlunge 1/3 HP External Filter Review:

Introduction

The AS ColdPlunge 1/3 HP with External Filter hits the sweet spot of the cold plunge chiller market. Compared to basic models, you get an LED touchscreen, high-capacity external filtration, and purpose-built cold plunge design — all at a competitive price point.

Design and Build Quality

This AS ColdPlunge model features a front-mounted LED touchscreen display, external 5-inch filter housing, and integrated circulation pump. The external filter is a significant upgrade over built-in mesh filters, removing debris, hair, and particles down to 20 microns for crystal-clear water.

Key Features

• LED Touchscreen: Precise digital temperature control with ±1°F targeting — a major upgrade over analog dials.
• External 20-Micron Filter: High-capacity filtration keeps water cleaner longer than basic mesh filters.
• Purpose-Built Design: Engineered specifically for cold plunge applications, not repurposed aquarium equipment.
• 24/7 Operation: Energy-efficient compressor designed for continuous daily use.

What to expect

We haven't tested this unit ourselves. This section is based on the manufacturer's published specs and general chiller sizing.

Cooling: AS ColdPlunge rates this 1/3 HP unit (about 4,500 BTU/hr) for tubs up to 100 gallons, down to 42°F. Expect slower pull-down near the top of that range and in hot weather; a lid and an insulated tub help.

Temperature control: The LED touchscreen gives digital temperature control, which is easier to set precisely than an analog dial.

Filtration: The external 5-inch, 20-micron filter catches finer debris than a basic mesh screen. How long water stays clean depends on sanitizer and use; see our water care guide.

Noise: The listed noise level is about 54 dB, so a garage or outdoor spot suits it better than a living space.

Energy use: The listed power draw is about 375W while the compressor runs. Monthly cost depends on climate, insulation and your electricity rate.

Verdict

The AS ColdPlunge 1/3 HP with External Filter delivers the best value in the cold plunge chiller market. The LED touchscreen and high-capacity filtration justify the premium over basic models, and it is designed for cold plunge use rather than repurposed from aquarium equipment. Perfect for DIY builders with tubs up to 100 gallons who want clean water and precise temperature control.

Sources

• NLM: Cold Water Immersion Benefits
• DOE: Pump Up Your Savings with Heat Pumps