Authentic Finnish heat, in the surroundings of Hampstead.
Our traditional sauna is built the way the Finns have built them for centuries: real timber, a deep bed of stones, and the soft rolling wave of steam they call löyly. It is the fire in Agni-Jal, and the first step of every visit.
Feel the heat as it was meant to be. Begin with a Weekend Discovery: two hours, a host to guide you, and full use of all four facilities.
A sauna built properly
Most saunas in London are an afterthought, a box in the corner of a gym. Ours was designed from the stones up by Studio Aqua Spazio London, specialists in sauna and wellness engineering for over 25 years.
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The heater. A HUUM CLIFF kiuas, sized for the room so the stones stay hot enough to give a clean, lasting löyly every time water meets them.
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The timber. Walls and benches in thermo aspen, chosen for its low heat absorption, so it stays comfortable to sit on at 85°C and gives off a gentle natural scent.
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The benches. Tiered seating so you choose your heat: the lower bench is gentler, the upper bench is where the heat is fullest.
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The air. Engineered ventilation brings fresh air in low and draws it out, so the heat feels soft and the air never stale or stuffy.
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The ritual. Aromatic infusions of birch, eucalyptus & pine are added to the löyly water.
The room runs at 80–85°C with 10–20% humidity. Pour water on the stones and the felt heat rises at once, then settles. You stay in control of every round.
Your sauna ritual at Agni-Jal
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Shower and dry off fully. A dry body sweats sooner.
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Start on the lower bench for 8–15 minutes. Move higher in later rounds if you wish.
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Add löyly a ladle at a time. Aim for a deep sweat, not distress.
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Step out and cool: the cold plunge or a cold shower.
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Rest in the relaxation lounge until your body has warmed itself back up. Sip water.
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Repeat for 2–3 rounds (up to 4 once you are experienced).
On your first visit, a host will guide you through the full ritual.
Frequently asked questions
Is the Finnish sauna right for me?
The sauna suits most healthy adults. Please speak to your GP before your visit if you are pregnant, have a heart condition, high or low blood pressure, or take medication that affects heart rate or sweating. Avoid alcohol before and during your session, and leave the room at once if you feel dizzy or unwell.
What temperature is your Finnish sauna?
It runs at 80–85°C with 10–20% humidity. The lower bench is cooler, so you can start gently.
What is löyly?
Löyly is the Finnish word for the wave of steam that rises when water is poured on hot stones. It raises the felt heat and is the soul of a true Finnish sauna.
What is the difference between a Finnish and an infrared sauna?
A Finnish sauna heats the air around you to a high temperature. An infrared sauna warms the body directly at a lower air temperature, around 45–60°C. Many members use both.
How long should I stay in?
8–15 minutes per round is typical. Listen to your body and leave whenever you wish.
What should I bring?
Robes, towels and toiletries are provided. Just bring yourself, swimwear and a water bottle.
Is Agni-Jal really for women only?
Yes. Agni-Jal is a private, women-only sanctuary in Hampstead, and entry is by invitation only.