Redwood Outdoors Sauna Review: Compare Every Outdoor Model

Redwood Outdoors has become one of the most searched-for backyard sauna brands in North America, and for good reason. Their Thermowood hemlock cabins ship to your driveway, assemble in an afternoon, and come paired with genuine Finnish Harvia heaters. If you're weighing one model against another, this guide compares the five outdoor saunas we carry, who each one is for, and how to choose between them.

The short version: every model is the same Thermowood hemlock build with a real Harvia heater, so the decision comes down to size, layout, and heater control, not build quality. You can't really go wrong on quality here, only on getting the size right for your space.

What every Redwood Outdoors sauna has in common

Before comparing models, it helps to understand what's shared across the lineup, because it's a lot. These features are consistent whether you buy the smallest Duo or the eight-person Garden.

Thermowood hemlock, not cedar. A common assumption is that these are cedar saunas. They're not. Redwood Outdoors builds with heat-treated (Thermowood) hemlock, and the larger Garden and Summit cabins use FSC-certified hemlock. The thermal-modification process bakes moisture out of the wood, which improves stability and resistance to rot and fungi without any chemical treatment. It's the right material for a structure that lives outside year-round.

Genuine Harvia heaters. Every model includes a Finnish-made Harvia 8kW electric heater, either the dial-controlled KIP or the Wi-Fi-enabled Spirit. These are real traditional saunas: you pour water over the rocks for steam, not infrared panels heating your skin.

DIY assembly. Pre-cut, interlocking panels with no sawing required. Most homeowners put these together in a few hours with basic tools. The heater wiring is the exception, and it needs a licensed electrician and a 240V circuit.

An outdoor-ready package. Roof shingles, an interior light, sauna rocks, a felt hat, and a doormat come included across the line, so you're not buying a shell and sourcing the rest.

The Redwood Outdoors sauna lineup at a glance

Here's how the five outdoor models compare on the things that actually drive the decision:

Redwood Outdoors Duo Sauna (2-person)

The Duo Outdoor Sauna is the entry point to the line, and the most-searched model for a reason: it's the one that fits where the others won't. The compact two-person footprint and clean, minimalist styling are designed for smaller backyards and urban spaces.

Despite the smaller size, it doesn't cut corners. You still get the same Harvia KIP 8kW heater and the same Thermowood hemlock construction as the larger cabins. If it's you and one other person, or your yard is tight, this is the practical pick.

Redwood Outdoors Cabin Sauna (4-person)

The Cabin Outdoor Sauna hits the size most people actually want. Four-person capacity is enough for a family or a couple of friends without committing to a six-seat footprint, and the squared cabin profile reads more architectural than a barrel. It looks like a deliberate structure, not a novelty.

It's offered with either the dial-controlled KIP heater or the Wi-Fi Spirit. If you're not sure what size you need, this is the safe default that suits the widest range of backyards.

Redwood Outdoors Barrel Sauna (6-person)

The Barrel Outdoor Sauna is the shape most people picture when they think "sauna." The rounded barrel design isn't just aesthetic. The curved ceiling reduces the dead air above your head, so the cabin heats efficiently and circulates warmth around the bathers.

It seats six, includes a solid flat floor kit and wall-mounted backrests, and comes with your choice of KIP or Spirit Wi-Fi heater. Choose this one if the traditional look is the point.

Redwood Outdoors Summit Sauna (6-person)

The Summit Outdoor Sauna is the Barrel's six-person capacity in a squared, modern cabin with extra headroom. It's built from FSC-certified hemlock treated with Redwood Outdoors' Thermowood process, and the taller interior makes it more comfortable to stand and move around than a barrel of the same capacity.

If you want six seats but prefer the clean lines of a cabin to the rounded barrel, the Summit is the one to look at.

Redwood Outdoors Garden Sauna (8-person)

The Garden Outdoor Sauna is the flagship. Eight-person capacity, an extra-wide upper bench, and a two-tier layout that lets bathers pick between hotter and cooler seating zones. Large tempered-glass windows open the space up, and there's storage under the benches for your bucket and ladle.

It's offered with your choice of the dial-controlled KIP heater or the Harvia Spirit Wi-Fi with the Xenio CX45 remote kit, which lets you preheat from the MyHarvia app on your phone. This is the one for entertainers and big households.

KIP vs. Spirit Wi-Fi: which Harvia heater?

Every model is offered with one of two Harvia heaters, and it's the same choice across the line. Both are 8kW, both heat the same way, and both let you run a dry sauna or pour water over the rocks for steam. The only real difference is how you turn them on and control them.

Harvia KIP. The simpler, more affordable option. Controls are built into the heater itself: a dial for temperature and a timer. You set it when you get to the sauna and it heats up from there. Nothing to connect, nothing to update, nothing that can lose a signal. If you want fewer things that can go wrong, this is it.

Harvia Spirit Wi-Fi. The same heater performance with app control added. It pairs with the MyHarvia app through the included Xenio remote kit, so you can start the sauna from your phone and have it preheated by the time you walk out. The trade-off is a slightly higher price and the setup of getting it on your network.

The honest summary: if you'll use the sauna on a routine and want it ready when you arrive, the Spirit Wi-Fi earns its premium. If you'd rather keep it simple and don't mind a short wait after you flip it on, the KIP does everything else identically. Neither choice affects how the sauna feels once it's hot.

How to choose your Redwood Outdoors sauna

The decision is shorter than it looks, because build quality is consistent across the range. Work through it in this order:

1. Start with capacity. Two people, get the Duo. A family, the Cabin. Six, the Barrel or Summit. Eight or regular entertaining, the Garden.

2. Then pick a silhouette. At six people, the only real difference between Barrel and Summit is rounded-traditional versus squared-modern with more headroom.

3. Then decide on heater control. KIP for simple dials, Spirit Wi-Fi for phone control and preheating, as covered above. It's the same choice on every model.

4. Confirm the basics. A level pad, 18 to 24 inches of clearance from structures, and a 240V circuit installed by an electrician.

Whichever model you choose, the heater is the same class and the wood is the same Thermowood hemlock. Buy for the size you'll actually use most weeks of the year, not the largest one you can fit. A sauna that's the right size gets used, and consistency is what delivers the benefits. You can compare the full range on our outdoor saunas page.

Frequently asked questions

Are Redwood Outdoors saunas cedar?

No. Redwood Outdoors outdoor saunas are built from heat-treated (Thermowood) hemlock, and the Garden and Summit use FSC-certified hemlock. The thermal-modification process improves stability and resistance to rot without chemicals, which is why hemlock Thermowood is used rather than cedar.

Are they traditional or infrared saunas?

Traditional. Every outdoor model includes a Finnish Harvia electric heater that warms a cavity of sauna rocks. You can run it as a dry sauna or pour water over the stones for steam. They are not infrared cabins.

How hard are they to assemble?

The cabins use pre-cut, interlocking panels with no cutting required, and most homeowners complete assembly in a few hours with basic tools. The heater itself must be wired by a qualified electrician to a 240V circuit and local code.

Which Redwood Outdoors sauna is best for a small backyard?

The Duo. Its compact two-person footprint is designed specifically for smaller and urban yards, while keeping the same heater and Thermowood hemlock construction as the larger models.

What's the difference between the KIP and Spirit Wi-Fi heater?

Both are 8kW Harvia heaters. The KIP uses simple built-in control dials; the Spirit Wi-Fi adds app control through MyHarvia so you can preheat the sauna remotely. Performance and steam capability are equivalent.