Replacement Sauna Heaters

Electric vs. Wood-Burning Replacement Heaters

Most replacement heater projects fall into one of two categories: swapping out a failed electric unit or upgrading a wood-burning stove that's seen better days. The choice between the two usually comes down to what's already in place.

If your sauna is wired with a dedicated 240V circuit, an electric sauna heater is the straightforward path. You'll match the kilowatt rating to your room size, confirm the voltage and phase, and have your electrician connect the new unit to the existing wiring. Electric heaters from HUUM and Harvia range from 2.2kW for compact one-person rooms up to 18kW for large commercial spaces — and most wall-mounted models bolt into the same bracket positions as older heaters.

Wood-burning replacement stoves don't need electrical work at all, but you'll want to verify your existing chimney setup. Interior-feed stoves like the Harvia M3 vent through the ceiling or wall; through-the-wall (LS) models from HUUM let you load firewood from outside the sauna. If your current stove is interior-feed and you want to switch to outside-feed, plan for some chimney modifications.

How to Size Your Replacement Sauna Heater

Start with cubic footage

Measure your sauna's interior length, width, and height in feet and multiply all three. That gives you the cubic footage your heater needs to cover. The general rule is 1 kW per 45–50 cubic feet of sauna space. A 6' x 5' x 7' room is 210 cubic feet, which puts you in the 4.5–6kW range. If you're between two sizes, go with the larger heater — you can always dial it back, but an undersized unit will struggle to reach temperature.

Adjust for glass, insulation, and placement

Glass doors and windows lose heat fast. Add roughly 15% to your cubic footage for each glass surface. Outdoor saunas or rooms with thinner insulation should bump up by 1–2kW to compensate for heat loss, especially in colder climates. Our sauna heater buyer's guide walks through the full sizing process with brand-specific recommendations.

Match the electrical specs

Before ordering, check your existing circuit. Most residential heaters run on 240V single-phase power; commercial installations often use 208V three-phase. The amperage draw depends on the kW rating — a 6kW heater typically pulls 25 amps, while a 9kW unit draws around 37.5 amps. Each product page lists exact electrical requirements so your electrician can confirm compatibility before you buy. Always have a licensed electrician handle the connection.

Brands We Carry

HUUM is an Estonian manufacturer known for striking modern design and high stone capacity. The HUUM Drop is a popular wall-mounted replacement for home saunas (4.5–9kW), while the HUUM Hive and Hive Mini cover larger rooms with floor-standing installations that hold 330–595 lbs of stones. HUUM's wood-burning Hive Flow stoves are built for serious loyly — they hold up to 330 lbs of stones and come in interior-feed and through-the-wall configurations.

Harvia is Finland's most established sauna heater manufacturer and the brand we recommend most often for reliability. The Harvia KIP series is a compact wall-mounted electric heater with built-in controls — it's one of the most common replacement choices for home saunas from 100 to 425 cubic feet. For larger spaces, the Harvia Cilindro holds up to 264 lbs of stones and delivers dense steam. On the wood-burning side, the Harvia M3 at 16.5kW is a proven workhorse for mid-size saunas, and the Harvia Pro series handles rooms up to 1,271 cubic feet.

Saunum takes a different approach with a patented air-mixing system built into the heater itself. A quiet fan circulates hot air from the ceiling down to floor level, eliminating the typical "hot head, cold feet" problem. The Saunum Air 5 (4.8kW) and Air 7 (6.4kW) include WiFi control, a Himalayan salt reservoir, and an aromatherapy dispenser — all built in. They're a premium option, but if you've ever wished your sauna had more even heat distribution, they're worth a look.

Amerec fills a niche most other brands don't. The Amerec Junior at 2.2kW is one of the smallest electric sauna heaters available, covering rooms up to 100 cubic feet. It's available in both 120V and 240V versions, making it a practical replacement for compact one-person saunas.

What's Included and What You'll Need

Every replacement heater ships with the heater unit itself. Electric models require sauna stones (sold separately or bundled in our heater packages) and a compatible controller — some heaters have built-in controls, others need a separate wall-mounted unit. Wood-burning stoves need stones and a chimney kit matched to your venting setup.

If you'd rather get everything in one box, our heater packages bundle the heater, stones, and controller together at the same price as buying them individually. It's purely a convenience play — no markup, no mystery about compatibility. We also carry heater guard rails, replacement sauna stones, and standalone controllers if you only need to replace part of your setup.

All orders over $200 ship free within the US, and every shipment includes freight insurance. Our team is available by phone or live chat to help you match the right heater to your sauna — bring your room dimensions and current heater specs, and we'll point you to the right model.