If you’ve ever fallen down the rabbit hole of sauna design research, you’ll know it can go from “oh, this looks fun!” to “is insulation toxic when heated?” in about five minutes. That’s been me since last December (oops!).
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Sauna Research Overload
It all began last Fall when my husband casually said, “We should get a sauna!” Naturally, I dove into home sauna research, which is how I stumbled across Trumpkin’s notes on building a sauna.
If you haven’t read them yet, be warned: they’re fascinating, incredibly detailed, and just a little intimidating. After reading through, I was convinced there wasn’t a single decent prefab sauna in the U.S. — and that if I wanted a true Finnish sauna experience (don’t forget your sauna hat!), I’d have to build one myself.
Of course, as with most things, I might have overthought it a little. After spiraling through forum threads, Reddit debates, and DIY sauna builds, I realized there might be a little flexibility in how “perfect” a sauna needs to be.
That’s when I found a lightly used Almost Heaven Bridgeport 6-Person Sauna locally—and I jumped on it. It was a fantastic deal, and I figured I could make a few small adjustments if needed to fine-tune the experience. Spoiler: it’s been amazing.
The Most Important Principle: Feet Above the Stones
If you only remember one thing from all of Trumpkin’s advice (and the advice of other sauna enthusiasts), it’s this: keep your feet above the stones. This is the golden rule for sauna comfort.
There’s some wiggle room. In our sauna, our feet are close to the top of the stove—slightly below, but not dramatically so—and it’s perfectly adequate. We don’t notice a significant temperature difference between our feet and the rest of our body, which is what really matters.
By contrast, barrel saunas clearly demonstrate why this principle exists. With benches set too low and only one seating level, your feet never warm up, while your face gets blasted by steam. Barrel saunas are often too small overall, leaving you hot-cold-confused instead of relaxed. Cute for Pinterest, but not the most functional choice. And yes, I’ve tried them — trust me, this rings true.
Sauna Size: Comfort Over “Ideal” Dimensions
Trumpkin’s notes go deep into ideal sauna size and dimensions, and while he’s correct that a larger sauna distributes heat more evenly, there are trade-offs. Larger saunas take longer to heat up and cost more to run.
I was worried our ceiling might be too low — especially for my tall husband — but in practice, it works perfectly. We went with a six-person sauna for two people, and it’s just right. Much like tents, a six-person sauna comfortably fits about three people, so if you’re choosing a size, go slightly larger than you think you need.
The key takeaway? Don’t get too caught up in hitting the “ideal” dimensions. Comfort, bench proportions, and heat distribution matter far more than strict adherence to measurements.
Heater Capacity, Glass, and the Overall Sauna Experience
One lesson I learned (and one most sauna enthusiasts agree on) is that your sauna heater capacity can compensate for many potential issues.
According to Trumpkin, the general guideline is roughly 1 kW of sauna heater power per 45–50 cubic feet of sauna space, adjusted upward if you have glass panels or less insulation. For our 6-person sauna (~300 cubic feet), an 8kW Harvia sauna heater is perfect.
I also worried about the glass front causing heat loss—but being able to look out at the trees while we sweat it out is totally worth it. The view adds a sense of calm that makes the whole backyard sauna experience feel elevated.
So… Should You Build or Buy a Sauna?
If you love a project and want to nerd out on every single detail (and don’t mind the learning curve), building your own sauna can be incredibly rewarding.
But if you’re like me — wanting a solid, enjoyable sauna without a year of research paralysis — a quality prefab sauna kit can absolutely deliver a true Finnish sauna experience.
For us, the Almost Heaven Bridgeport 6-Person Sauna hit the sweet spot: well-built, efficient, and customizable enough that we could tweak it later if needed. Every session so far has been pure bliss.
Final Thoughts on Home Saunas
Whether you choose to build or buy a sauna, the most important thing is to understand the key comfort principles—heat distribution, proper bench height, and a heater with enough power to create real löyly (that beautiful wave of steam).
I’ll share more soon about how we’ve customized our sauna to elevate our experience even more, so be sure to tune in next week! Check out the other projects on the One Room Challenge blog and on Apartment Therapy for featured projects!
Would you build or buy your own sauna? I’d love to know how deep down the research rabbit hole you’ve gone—or if you’ve found your own favorite setup. Drop your thoughts in the comments below!