Article: Harvia KIP vs Spirit Wi-Fi: Which Sauna Heater Should You Choose?

Jun 24, 2026Outdoor Saunas

Harvia KIP vs Spirit Wi-Fi: Which Sauna Heater Should You Choose?

For most buyers, the Harvia KIP is the better value and the Harvia Spirit Wi-Fi is the better experience. Both are 8kW, UL-listed electric sauna heaters that deliver the same gentle burst of steam, so the real decision comes down to two things: do you want to start your sauna from your phone, and do you live somewhere very cold? The KIP keeps it simple and costs less. The Spirit adds Wi-Fi app control and heats quickly and efficiently in nearly any climate, for roughly $1,500 to $1,700 more once it is built into the sauna. Here is exactly how they compare and which one to pick.

What is the difference between the Harvia KIP and Spirit?

Every Redwood Outdoors sauna is offered with one of two Harvia electric heaters, and both are 8kW, UL-listed, and built to last. The KIP is the traditional, compact workhorse: a proven heater with a simple control that does one job well at the lowest price. The Spirit is the step-up option, with optional Wi-Fi so you can schedule and start your sauna from the MyHarvia app, plus quick and efficient heating that holds up better in colder climates.

What they share matters too. Both give you the same gentle, traditional steam when you ladle water over the rocks, both carry UL listing, and both need the same routine care. So this is not a question of one heater being clearly better. It is a question of how much convenience and cold-weather performance you want to pay for.

Harvia KIP vs Spirit Wi-Fi: side by side

Feature	Harvia KIP	Harvia Spirit Wi-Fi
Power	8kW	8kW
Wi-Fi / app control	No	Yes, via the MyHarvia app
Cold-climate heating	May underperform in extreme cold	Quick and efficient in most climates
Steam	Gentle, traditional	Gentle, traditional
Design	Compact	Compact
UL listed	Yes	Yes
Relative price	Lower	Around $1,500 to $1,700 more (built in)
Best for	Value buyers, mild climates, simplicity	Convenience seekers, cold climates

Is the Wi-Fi upgrade worth it?

This is the heart of the decision. With the Spirit Wi-Fi and the MyHarvia app, you can start the sauna from inside the house, set a schedule so it is hot when you get home from work, and check the temperature from your phone. A sauna takes time to heat up, so being able to start it remotely is the difference between waiting around and walking straight into a ready sauna. If you plan to use your sauna often, that convenience pays off every single session.

It is worth it if you value that day-to-day convenience or live somewhere with hard winters, where the Spirit's efficient heating is a real advantage. It is not worth it if you are happy to flip a switch and wait, or if you are in a mild climate and would rather put the savings toward accessories or a larger sauna. There is no wrong answer here, just the one that fits how you will actually use it.

Which Harvia sauna heater is right for you?

Use this simple rule:

Choose the KIP if you want the best price, you live in a mild to moderate climate, and you do not mind starting the sauna manually and giving it time to heat.
Choose the Spirit Wi-Fi if you want to start and schedule your sauna from your phone, you sauna frequently, or you live somewhere with cold winters and want fast, efficient heat-up.

Both heaters come on every model in the Redwood Outdoors range, so you are free to pick the size and shape you love first, then choose the heater that fits your budget and habits. Two popular starting points:

Redwood Outdoors Cabin 4-person outdoor sauna

Does the heater change the sauna itself?

No. The wood, the build, the benches, and the size are identical whether you choose the KIP or the Spirit Wi-Fi. You are only choosing the heater and its controls. Every Redwood Outdoors model, from the 2-person Duo up to the 8-person Garden, is sold with both heater options, so you can match the heater to your budget and climate without compromising on the sauna you want. If you are unsure, the KIP is the safe, no-regrets choice for most mild-climate backyards, and you can always step up to the Spirit for the smart features.

Frequently asked questions

Is the Harvia Spirit Wi-Fi worth it?

Yes, if you will use your sauna regularly or live in a cold climate. The Wi-Fi lets you start and schedule the sauna from the MyHarvia app so it is ready when you are, and the Spirit heats quickly and efficiently in most climates. If you are in a mild area and happy to start it manually, the KIP saves you money for the same steam.

Can you control a Harvia sauna from your phone?

Yes, with the Spirit Wi-Fi heater and the MyHarvia app you can turn the sauna on, set a schedule, and monitor the temperature from your phone. The KIP does not include Wi-Fi or app control, so it is started at the heater.

Is an 8kW heater big enough for my sauna?

Both the KIP and Spirit options offered on these saunas are 8kW, matched by Redwood Outdoors to the sauna sizes they come with. Choose your sauna size first and the correct heater power comes with it, so you do not need to calculate it yourself.

Does the Harvia KIP work in cold climates?

The KIP works well in mild to moderate climates but may underperform in extreme cold. If you live somewhere with hard winters and want fast, reliable heat-up, the Spirit Wi-Fi is the better choice.

Can you add Wi-Fi to a KIP heater later?

The KIP is sold without Wi-Fi, so if app control and remote scheduling matter to you, choose the Spirit Wi-Fi from the start rather than planning to add it later.