AS 1 HP vs AS 1/3 HP
AS ColdPlunge 1 HP versus 1/3 HP is a classic headroom-versus-efficiency decision for DIY builders choosing a dedicated chiller.
Quick Verdict
AS ColdPlunge 1 HP
It cools faster, handles larger tubs, and gives hot-climate users far more margin before performance drops.
Choose AS 1 HP if:
- Your tub is over roughly 100 gallons or you live in a hot climate.
- You want fast pull-down times and thermal headroom for daily use.
Choose AS 1/3 HP if:
- Your tub is small and you care more about a cheaper entry point.
- You are building a modest setup and do not need sub-40 performance on large water volume.
Side-by-Side Comparison Table
| Feature | AS 1 HP | AS 1/3 HP |
|---|---|---|
| Format | Purpose-built external chiller | Budget dedicated chiller |
| Capacity | Up to 250 gallons | Optimal under 80 gallons |
| Cooling | 1.0 HP compressor | 1/3 HP compressor |
| Temperature range | 37°F - 95°F | 42°F - 95°F |
| Power | ~800W on 110V | ~360W on 110V |
| Maintenance | External 20-micron filter and pump | Built-in pump and reusable metal filter |
| Footprint | Separate chiller plus hoses | Compact standalone box with hoses |
| Best for | Large tubs and hot-climate setups | First-time buyers on smaller tubs |
What is the real difference between these two chillers?
Power headroom. The AS ColdPlunge 1 HP review is built for larger tubs, hotter environments, and buyers who do not want to outgrow the chiller later. The AS ColdPlunge 1/3 HP review is the sensible budget choice for smaller tubs where electricity costs and upfront price matter more than brute force.
That means the smaller unit is not a bad buy. It just becomes the wrong buy faster once water volume or ambient temperature rises.
Which one is cheaper to own?
The 1/3 HP wins on upfront cost and typically on monthly electricity, but only when used inside its lane. If you pair it with too much water volume, it runs longer, recovers slower, and loses the efficiency advantage you thought you were buying.
The 1 HP draws more power, but it often gets to target faster and cycles less once there. For large tubs or aggressive temperature targets, that makes it the more realistic long-term option, especially if you are also following a disciplined water care routine and using the setup frequently.
Which one should builders choose?
Choose the 1/3 HP if your tub is under roughly 80 gallons, you plunge for recovery rather than extreme temperature chasing, and your budget is tight. It is the better first step for many small DIY builds.
Choose the 1 HP if you want a serious long-term system. It is the better answer for stock tanks with larger volume, for bigger insulated tubs, and for anyone who does not want summer weather to dictate the quality of the plunge.
Bottom line
The 1/3 HP is the value play. The 1 HP is the safer recommendation. If you are on the line between them, buy the bigger chiller once and stop thinking about it.