Ten Versions of Cold

Three years of building plunges. Here's what we learned — and why we're all in.

Three years ago I built our first cold plunge in the corner of the shop. (The real origin story starts even humbler — with a horse trough.) Cedar frame. Half-horsepower chiller. Low-flow pump. It worked. Those early units are still running in people's backyards today, and the people who own them love them. Cold water, beautiful cedar — we knew how to do that part from day one.

But "works" has never been the finish line here. We build saunas people hand down to their kids. If we're going to make something, we're going to take it as far as it can go. That first plunge was also before we got into metal fabrication — before stainless and aluminum entered the shop and changed what we could build.

So we built it again. And again. Nine more times.

The plunge we build today is version ten. Here's what got us there.

The water is the product

A cold plunge isn't a tub that happens to be cold. It's a small body of water fighting entropy 24 hours a day. Bather load, sunlight, a Texas August, a Michigan January. That first half-horse chiller did its job, but we watched it work hard on the hottest days and knew there was headroom. Same with the pump. It circulated. We wanted water that moves.

Today: 1 HP commercial chiller — same class of equipment we put in spas and athletic facilities — pulling to 36°F and holding it, summer or winter. And the pump runs 24/7. There's no off switch. On purpose. Moving water stays clean, stays sanitized, doesn't freeze. Ten versions of watching what actually happens taught us that.

More water is better water

Most plunges on the market hold 105 to 110 gallons. Ours holds 170. That's not a flex, it's physics. More water holds temperature between plunges, handles more bathers, stays cleaner longer. The category is under-watered. We're not.

Wood where it belongs, metal where it matters

V1 was cedar-framed because cedar was what we'd mastered. Then metal fab came into the shop and everything opened up. Now: stainless steel tub, powder-coated aluminum frame that will never rust, and Grade A cedar doing what cedar does best — being the most beautiful thing in your backyard. Same cedar, same stains, same hands that build our saunas. The plunge belongs next to the sauna, because it comes out of the same shop.

We show our work

We publish our full water care protocol. The actual chemistry. Almost nobody in this category does that. After ten versions we know exactly what we built, so we don't mind showing the math. It's all in the Cold Plunge User Guide, and the V10 spec sheet is right there too — every number, no email gate.

Cold has a full-time job now

This isn't a side project anymore. David H is our full-time cold plunge specialist — his whole job is taking everything ten versions taught us and pushing it further. Water chemistry, sanitation, the details nobody sees. He's in the shop dialing it in every day.

And when you've got questions — siting, contrast protocols, the thing you're half-embarrassed to ask — just call. Schedule a call. We're here to bring the contrast.

Why we're doing this

The plunge is the second half of the sauna. Heat, then cold. The oldest ritual in the world — people have been doing it on frozen lakeshores for centuries, and the science backs the tradition (we wrote that up too). We spent years earning our stripes in heat. Now the same obsession is pointed at cold.

Nine versions came before this one. Every one taught us something. Version ten is what's left when you've solved it.

We're serious about plunging. And the only thing that can make a Nightjar sauna better is a Nightjar cold plunge sitting right next to it.

Come get cold with us.

— Dave, Nightjar Sauna · Grand Rapids, Michigan

Go deeper:

• The Nightjar Cold Plunge — see the machine
• V10 Spec Sheet (PDF) — every number, nothing hidden
• Cold Plunge User Guide — water care, protocols, the works
• Where Contrast Therapy Is Headed — why we're building for this
• Schedule a call — you'll get Dave or Eric, not a call center