Planning a home sauna in New Zealand
A home sauna is settled by a short run of decisions: whether it sits inside the house or out in the garden, how large it is, how it's heated, what it's lined and clad in and what it costs to build.
Every Heritage sauna is drawn for one property, so the answers shift from home to home.
01. Indoor or outdoor
Both work, and the choice rests on the space you have. Indoors, the design works around the room it's given, from its ceiling height to the way air moves through the house. Outdoors, the sauna stands as its own small building, and we like a bench long enough to lie down on, so the interior sits at around 2100 x 1800 mm with the depth adjusted to the site.
02. Choosing the spot
Four things decide where an outdoor sauna goes: how the ground falls and drains, which way the prevailing wind blows, where the sun sits through the day and how easily a build team can reach it. A door turned away from the wind, with the evening sun on it, makes a very different sauna from one tucked against a cold fence line.
Glazing is set on the view from the upper bench, so it's worth standing where that bench would be before anything is drawn. A slope is rarely a problem (we often set the sauna on screw piles on tricky ground), and on a roof terrace our architect reviews the building's plans to confirm it can carry the load.
03. Size and layout
Size follows how many people will use the sauna at once and how they'll use it. A bench long enough to lie down on sets the length of most outdoor builds at around 2100 mm inside. A garden sauna Heritage designed near Omaha measures 2100 x 1600 mm inside, lined in hinoki and heated by a HUUM Drop 6 kW. Ceiling and bench heights are drawn together. Heat gathers at the top of the room, and the upper bench is where it's felt most.
04. Traditional or infrared
A traditional sauna heats the air and a mass of stones. Water thrown on the stones sends a wave of steam across the room, which the Finns call löyly. An infrared cabin warms the body directly from heated panels and runs at a lower air temperature, with no stones and no steam. Heritage builds around HUUM stone heaters, where the weight of stone sets how soft and lasting the löyly feels.
05. Electric or wood-fired
The choice follows how you'll use the sauna. At a main home, people often choose electric, since it can be started from an app on their phone. At a holiday home, many prefer a wood-burning heater for the soft light of the flame and the sound of the wood as it burns.
An electric heater is wired and commissioned by a registered electrician, and every electric HUUM heater we supply comes with a UKU Glass control panel. A wood-fired heater needs no wiring apart from lighting. Both arrive with their stones and a safety rail.
06. The timber inside
Hinoki cypress is the timber we recommend for the inside of a sauna, durable enough to need no treatment at all and carrying hinokitiol, a natural compound with antibacterial properties. It gives off a light, lemony scent as it warms. Sugi, the Japanese cedar, comes second, softer in the grain and warmer in tone. Both come from plantation forests in Japan and are GOHO certified, meaning legally harvested and tracked through the supply chain.
New Zealand grown redwood is an alternative, also plantation grown, though it needs treating when it's milled into panels. Every Heritage interior is left uncoated, so volatile organic compounds stay extremely low.
07. Cladding and roof
The outside is clad to sit with the house it belongs to, and any home's cladding can be matched: board and batten, horizontal bevel-back, rusticated or vertical shiplap weatherboards, cedar shingles, burnt yakisugi, corrugated iron or stone.
The roof is New Zealand made Colorsteel in a Eurospan profile, a standing seam with no exposed fixings, made at Glenbrook in Auckland. Between the linings, wool insulation made in Onehunga or Christchurch from yarn left over by the carpet industry copes with the heat and moisture of every session.
08. Building consent
A single-storey detached building under 10 m² doesn't need building consent under Schedule 1 of the Building Act 2004, and there's no minimum distance from a boundary. Between 10 and 30 m², it must sit at least one metre from the boundary and be built by a licensed builder, which we are. An outdoor shower fed from an existing hose tap doesn't need consent either.
09. What a home sauna costs
Saunas range from $45,000 to $90,000 + GST, depending on the materials, the design and how the sauna is shaped to its space. The site visit is free anywhere in New Zealand.
When you commission the design
Before fabrication, to order materials and start the build
When the sauna is built and working on your property
10. Timing and care
From a signed proposal to handover takes 10 to 16 weeks, and builds are scheduled in the order proposals are signed. Parts are made in our workshops in Auckland and Queenstown and assembled on site, which keeps the time on your property short.
The timber never needs refinishing. A wipe with a soft cloth and water is enough, with a mild detergent if needed. Please don't sand it: the benches are finished with a blade in our workshop, and sanding opens the fibres so moisture gets in far more easily.
Questions about home saunas
How much does a home sauna cost in New Zealand?
A Heritage sauna costs between $45,000 and $90,000 + GST, depending on the materials, the design and how it's fitted to the site. Payment is staged at 5% for design, 50% before the build and 45% on completion.
Do I need building consent for a home sauna?
Not if it's a single-storey detached building under 10 m². Between 10 and 30 m², it can be built without consent when it sits at least one metre from the boundary and is built by a licensed builder.
How big should a home sauna be?
Large enough for the number of people who'll use it at once, with a bench long enough to lie down on. Outdoor saunas sit at around 2100 x 1800 mm inside, with the depth adjusted to the site.
Can a home sauna go inside the house?
Yes. Heritage builds indoor and outdoor saunas, and an indoor design works around the constraints of the room and the building.
What can be added to a home sauna?
An outdoor shower, a cold plunge, a changing room, a deck, lighting and glazing can all be designed in.