From ฿48,500 Free Delivery Built to order · 6–8 weeks
Diooist Sauna Heaters · Sauna Accessories

Prism Heater

The Black Prism is our premium sauna heater, featuring a sleek tower design with clean geometric lines. This sophisticated heater combines modern aesthetics with exceptional heating performance, making it the centrepiece of any high-end sauna installation.

From ฿48,500
Delivery time 3-5 weeks · deposit refundable up to 3 days*
Island delivery (e.g. Koh Samui, excl. Phuket) — ฿1,500 ferry surcharge added at checkout.

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Power 3kW Included in base
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Choose by sauna internal volume — see specs below

Add multiple products, then email yourself the full quote or checkout.

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Free consultation
Free delivery in Thailand
1–2 year warranty
After-sales support
Frequently Asked Questions
What size heater do I need for my sauna?
Calculate the interior volume of your sauna room in cubic metres (length × width × height). As a general guide, allow approximately 1KW per 1.5–2 cubic metres. For outdoor saunas or rooms with large windows or glass doors, add 20% to account for heat loss. Use our Heater Size Guide above to match the right heater to your space.
What makes the Prism heater premium?
The Prism is our top-tier heater line, featuring several distinguishing features. The sleek geometric tower design creates a striking visual element. Heavier-gauge construction (20.5kg vs 10–13kg for standard models) ensures durability and long service life. The enclosed stone chamber and clean lines deliver a minimalist aesthetic suited to high-end installations. Premium materials and finish quality throughout.
Why choose the Prism over other heaters?
Choose the Prism if design aesthetics are a priority, if you're building a premium sauna for a luxury home or boutique commercial facility, or if you prefer the clean look of an enclosed heater to open-basket designs. The robust construction also makes it suitable for demanding use environments.
Why is the Prism more expensive than other heaters?
The higher price reflects premium construction quality, heavier-gauge materials, sophisticated design engineering, and superior finish quality. The Prism is built for discerning customers who value both performance and aesthetics in their sauna equipment.
How does the Wi-Fi control work?
The system includes a compact wireless adapter that plugs into the controller. Once connected to your Wi-Fi network, you download the free app to your smartphone. The app lets you turn the sauna on/off, set the temperature, adjust the timer, and monitor current conditions from anywhere with internet access.
Is the Wi-Fi system difficult to set up?
Not at all. The adapter plugs directly into the controller and connects to your Wi-Fi network like any smart home device. The app guides you through pairing in a few minutes. No technical expertise or professional setup required.
Can I still use the wall controller if the Wi-Fi is down?
Yes. The external wall controller works independently. Wi-Fi adds remote convenience, but the physical controller provides full functionality at all times, even without an internet connection.
Can I install this heater myself?
The heater requires professional electrical installation by a licensed electrician. While mounting the heater and setting up Wi-Fi is straightforward, connecting to your electrical supply must be done by a qualified professional to ensure safety and compliance with Thai electrical regulations.
How long does the heater take to warm up the sauna?
Expect 30–45 minutes to reach typical sauna temperatures of 80–90°C, depending on room size, insulation quality, and ambient temperature. The enclosed design efficiently dissipates heat through the stone chamber.
Are the sauna stones included?
Yes. Each heater includes 18–22kg of premium sauna stones (shipped in 2 boxes). These volcanic stones are specifically selected for sauna use and can withstand thermal shock from water contact without cracking.
What electrical supply do I need?
The heater operates on standard Thai 220–240V single-phase power. You will need a dedicated circuit with appropriate amperage (typically 30–40A, depending on heater size) and a correctly rated MCB. Your electrician will assess the capacity of your electrical panel.
Can I pour water over the stones to generate steam?
Yes. The enclosed design has openings that allow you to pour water onto the heated stones. The resulting steam (löyly) vents through the chamber. Use moderate amounts of water for best results.
Can I use this heater for an outdoor sauna?
Yes, but the heater itself must be installed inside the sauna room, protected from direct weather exposure. For outdoor saunas, select a heater size 20% larger than the calculated room volume to compensate for heat loss.
Is this heater suitable for commercial use?
The Prism is designed for premium residential and boutique commercial applications, including luxury spas, wellness studios, private clubs, and high-end hotel suites. For high-traffic commercial facilities requiring heaters over 9 kW, consider our Nest heater range, which offers up to 15 kW of capacity.
What is the warranty?
Heaters include a 1-year manufacturer's warranty covering defects in materials and workmanship. Warranty does not cover damage from improper installation, misuse, or normal wear of heating elements.

Have more questions? Chat with us

About this heater

Overview

Standing 80.5cm tall with a compact 31 x 31cm footprint, the Prism heater fits elegantly into corner installations whilst its vertical profile creates visual impact. The enclosed design provides a clean, minimalist appearance, whilst the internal stone chamber delivers high-quality steam production.

Built with heavier-gauge construction (20.5kg without stones), the Prism is engineered for demanding use and long service life. The matte black finish complements contemporary sauna interiors, particularly those featuring dark timber, stone accents, or modern minimalist design.

This heater includes Wi-Fi connectivity for smartphone control, plus an external wall-mounted controller with a digital LCD display. Control your sauna from anywhere using the free app, or adjust settings at the controller outside your sauna door.

The Wi-Fi system includes a compact wireless adapter that connects to your home network. Setup takes just minutes, and the app works with both iOS and Android devices.

Choose from four power options to match your sauna room size. All of our sauna heaters are TÜV Safety Certified.

What’s Included

  • Electric sauna heater unit prism design
  • External screen controller with digital LCD display
  • Wi-Fi adapter (plugs into controller for wireless connectivity)
  • Controller cable (for routing through the wall)
  • 18–22kg premium sauna stones (2 boxes)
  • Heater mounting brackets and hardware
  • Installation Manual (English)

Technical Specifications:

Heater Dimensions

  • Width: 31 cm
  • Depth: 31 cm
  • Height: 80.5 cm
  • Weight: 20.5kg (heater only, without stones)
  • Stone Capacity: 18–22kg
  • Finish: Matte black

Controller Specifications

  • Voltage: 220–240V single-phase
  • Power Options: 3KW / 4.5KW / 6KW / 9KW
  • Circuit: Dedicated circuit with an appropriate MCB required
  • Wiring: Hardwired installation (no plug)

Controller Specifications

  • Type: External wall-mounted with Wi-Fi
  • Display: Digital LCD screen
  • Temperature Range: 40–110°C
  • Timer: Up to 8 hours
  • Mounting: Outside sauna room
  • Wi-Fi: 2.4GHz wireless (adapter included)
  • App: Free iOS and Android application

Performance

  • Operating Temperature: 70–100°C (typical sauna range 80–90°C)
  • Heat-up Time: 30–45 minutes to reach 80°C (varies by room size)
  • Stone Heating: Direct contact for efficient steam production
  • Premium tower design with clean geometric lines
  • Sleek matte black finish for high-end interiors
  • Compact 31 × 31cm footprint fits corner installations
  • Tall 80.5cm profile creates visual impact
  • Heavy-duty construction (20.5kg) for demanding use
  • Enclosed design for a clean, minimalist appearance
  • Wi-Fi connectivity for smartphone app control
  • External wall-mounted controller with digital LCD display
  • Control your sauna from anywhere via iOS or Android app
  • Efficient internal stone chamber for quality steam
  • Suitable for premium residential and boutique commercial use
  • Quick heat-up time of 30–45 minutes
  • TÜV Safety Certified for peace of mind
  • 220–240V single-phase power (standard Thai electrical)
Delivery

Delivery
Free delivery throughout Thailand. Standard delivery timeframe is 3–6 weeks from order confirmation.
Heater, controller, Wi-Fi adapter, and stones ship separately (2 boxes total). Delivery to the ground floor or building loading dock. Stairs or lift access may incur additional handling fees.

Installation
Professional electrical installation required. The heater must be hardwired to a dedicated circuit by a licensed electrician.
The Prism heater can be floor-mounted or wall-mounted, depending on your sauna layout. The compact footprint and tall profile suit corner installations. Maintain a minimum 40cm clearance between the top of the heater and the ceiling.
The external controller requires a small hole through the sauna wall for the cable connection. Your electrician or installer can drill this during setup.
RonYen Sauna provides installation guidance but does not install standalone heaters. We recommend hiring a local electrician familiar with high-amperage appliance installation.
Wi-Fi setup is simple. The adapter plugs into the controller, connects to your home Wi-Fi network, and pairs with the app in minutes. No technical expertise required.

Installation typically requires:
Dedicated electrical circuit (30–40A depending on heater size)
Appropriate MCB/circuit breaker
Heat-resistant wiring rated for sauna conditions
Small wall penetration for controller cable
Wi-Fi network with 2.4GHz support
Adequate ceiling clearance (minimum 40cm above heater)

Warranty

If an electrical item stops working within the warranty period, we’ll send you a replacement free of charge.

Specifications

Dimensions
External310 x 310 x 805 mm
Performance
Temperature range60-105c
Heating time30-45 mins
Power & electrical
Power3 - 9kW
Voltage220-240v or 3 Phase Power
Common questions

Everything you want to know about saunas & heaters

Outdoor and indoor cabins, barrels, cylinders and sauna + shower combos — from a compact one-person unit up to ten-person commercial rooms, all customisable to your space. Browse saunas.

Western Red Cedar and Finnish Thermo Pine both handle heat and humidity beautifully; Hinoki is our premium pick. We’ll match the timber to your budget and location.

Outdoor saunas are fully weather-sealed for gardens, rooftops and pool decks; indoor models are built for bathrooms, gyms and spare rooms. Both use indoor-rated electric heaters.

Most home saunas run on a dedicated single- or three-phase circuit sized to the heater. We’ll confirm the exact electrical requirement in your quote.

Both are food-grade and corrosion-resistant; 316 adds extra protection for coastal and chlorinated environments. We recommend the right grade for your site. See ice baths.

Ice works to get started, but a chiller holds a precise temperature day after day with no effort — the easiest way to make cold therapy a daily habit.

Our chillers take the water down to around 3°C and hold it there. Most people plunge between 3–10°C depending on experience.

A built-in filtration and sanitation cycle keeps the water fresh for weeks. We’ll walk you through simple water care at handover.

We soft-open on 30 July 2026 in Chonburi (with Founding Member pricing) and fully open on 4 September — and booking is open now, so you can reserve a session ahead. Book a visit.

The Garden runs on advance bookings so every session has the space to itself — so book ahead if you can. That said, if you're passing and spot us, scan the sign at the gate or give us a call, and if there's room in the current session we'll happily wave you in.

Saunas, ice baths, a swimming pool and shaded lounge areas — everything you need for the full hot-and-cold circuit. Explore the garden.

The Wellness Garden is in Chonburi, easily reached from Bangkok and Pattaya. Full directions and parking details are on the garden page.

Yes — most saunas assemble in a day with two or three people and clear instructions. Prefer it done for you? Our team can handle the full install. Installation service.

Delivery to the spot, full assembly, levelling, heater fitting and a handover walkthrough so it’s ready to use the same day.

A firm, level base — a concrete pad, deck or paved area — plus a nearby power point. We’ll send a simple prep checklist before delivery.

Final connection should be made by a licensed electrician. We provide the full specification and can recommend trusted local contractors.

Yes — we deliver right across Thailand by freight, and ship internationally on request. Delivery details.

Most saunas are ready six to eight weeks from order. Once built, freight to your address typically takes a few days, with tracking provided.

Standard nationwide delivery is included. For tricky access — rooftops, tight lanes or upper floors — we’ll quote any crane or extra handling up front.

Everything ships in a purpose-built timber crate to protect the timber and glass in transit — and the crate is easy to dispose of or repurpose.

Still deciding? Talk to a specialist.

Get a straight answer on what suits your space, budget and the Thai climate — free and with no pressure.

Book a free consultation

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Talk to us before
you buy.

A sauna or ice bath is a long-term addition to your home or commercial space. Tell us about your project, your goals and your timeline — we’ll give you a straight answer, including what the right options are.

Free consultation. Phone call, video call, or visit our showroom in Ban Suan, Chonburi — Rön Yen Shop & Wellness Garden — by appointment. Tell us your space and budget, and we’ll talk through the options with no pressure to buy.

Ban Suan, Chonburi — 10 minutes from Central Chonburi

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