Harvia Glow Corner TRC90 9.0kW Sauna Heater – Corner-Mounted Pillar Heater – 8–14 m³ Capacity
£934.52 Inc VAT
🔥 Harvia Glow Corner TRC90 9.0kW Sauna Heater – Corner-Mounted Pillar Heater – 8–14 m³ Capacity
Crown your sauna corner with 50 kg of heated stone — pillar power meets effortless simplicity.
♨️ Product Overview
The Harvia Glow Corner TRC90 is a 9 kW corner-mounted pillar heater that transforms an unused corner of your sauna into a striking centrepiece. Designed and manufactured in Finland by Harvia, this triangular tower heater stands 1,100 mm tall and holds an impressive 50 kg of sauna stones — delivering soft, comfortable steam and even heat distribution across medium to large sauna rooms between 8 and 14 m³.
What makes the Glow Corner distinctive is its open lattice steel exterior, which leaves a generous amount of stone surface visible and accessible. This means you can control both the intensity and character of your steam: pour water directly onto the top of the stone pillar for a sharp, intense blast, or onto the exposed sides for a gentler, softer löyly. It is a heater that puts the bather in control of the sauna experience.
Operation is refreshingly simple. Built-in manual timer and thermostat controls are located at the front base of the heater — no separate control panel or digital unit required. Harvia’s patented integrated sensor system ensures the thermostat operates independently of stone placement, maintaining stable performance even after years of use. The thermostat also reacts quickly when stones cool down, bringing the heating elements back on promptly so stones are hot and ready for the next round of steam.
An integrated internal tunnel accelerates air circulation and doubles as a support structure for the heating elements, meaning stone deterioration over time does not affect airflow or heater performance. This internal tunnel with integrated heat sensor is a Harvia innovation unique to the Glow range.
🌟 Key Features
✅ 9 kW Power Output – Heats sauna rooms from 8 to 14 m³, suitable for family saunas, garden cabins, barrel saunas, and small commercial installations.
✅ Corner-Mounted Pillar Design – Triangular profile fits neatly into a corner, saving valuable floor space while creating a dramatic visual statement.
✅ 50 kg Stone Capacity – Generous stone load for excellent heat retention, soft steam production, and a long-lasting sauna session between top-ups.
✅ Exposed Stone Surface – Open lattice steel exterior reveals ample stone surface, allowing water to be thrown onto the sides or top for controllable steam intensity.
✅ Built-In Manual Controls – Simple, easy-to-use timer and thermostat switches at the front base of the heater — no separate control panel needed.
✅ Patented Integrated Sensor System – Thermostat operation is unaffected by stone placement, maintaining stable, reliable performance over years of use.
✅ Quick Thermostat Response – Heating elements react rapidly when stones cool down, ensuring stones are reheated promptly for continuous steam readiness.
✅ Integrated Internal Tunnel – Harvia’s proprietary design accelerates air circulation and supports heating elements, maintaining performance even as stones naturally deteriorate.
✅ IPX4 Splash-Proof Rated – Certified for reliable use in wet sauna environments.
✅ CE and EAC Certified – Fully compliant with European and Eurasian safety standards.
⚙️ Technical Specifications
| Specification | Value |
|---|---|
| Model / Type Code | TRC90 |
| Harvia Article Number | HTRC900400 |
| Power Output | 9 kW |
| Voltage Options | 230V 1N~, 230V 3~, or 400V 3N~ |
| Fuse Rating (400V 3N~) | 3 × 16 A |
| Fuse Rating (230V 1N~) | 1 × 40 A |
| Supply Cable (400V 3N~) | 5 × 2.5 mm² |
| Supply Cable (230V 1N~) | 3 × 10 mm² |
| Electrical Frequency | 50/60 Hz |
| Control Type | Built-in manual switches (timer and thermostat) |
| Room Capacity | 8–14 m³ |
| Dimensions (H × W × D) | 1,100 × 330 × 330 mm |
| Net Weight (without stones) | 17.5 kg |
| Stone Capacity | 50 kg |
| Recommended Stone Size | Ø 5–10 cm |
| Heat-Up Time | Approximately 60 minutes (properly insulated room) |
| IP Rating | IPX4 |
| Installation | Floor-standing, corner-mounted (vertical) |
| Minimum Room Height | 2,000 mm |
| Minimum Floor Clearance | 20 mm |
| User Group | Households |
| Use Environment | Interior – wet area |
| Certifications | CE, EAC |
📏 Room Sizing Guide
The Harvia Glow Corner TRC90 is designed for sauna rooms between 8 m³ and 14 m³. To determine whether this heater suits your sauna, calculate your room volume and apply the appropriate adjustment factors.
Basic Formula:
Room Volume = Length (m) × Width (m) × Height (m)
Adjustment Factors:
| Condition | Adjustment |
|---|---|
| Glass door or windows | Add +1.5 m³ per m² of glass |
| Uninsulated or log walls | Add +25–50% to calculated volume |
| Outdoor or barrel sauna | Add +25–30% to calculated volume |
| Ceiling height above 2.3 m | Add the extra volume above 2.3 m |
Worked Example:
📍 Example Room: 2.4 m × 2.0 m × 2.2 m
- Base volume: 10.56 m³
- Glass door (0.8 m × 2.0 m = 1.6 m²): +2.4 m³
- Total calculated volume: 12.96 m³
- This 9 kW heater covers 8–14 m³: ✅ Well suited
📍 Example Room: 2.8 m × 2.5 m × 2.3 m
- Base volume: 16.1 m³
- No glass, well-insulated walls
- Total calculated volume: 16.1 m³
- This 9 kW heater covers 8–14 m³: ❌ Too large — consider a higher-output Harvia heater
💡 The Glow Corner’s 50 kg stone load provides excellent thermal mass, which helps maintain a stable temperature even in rooms at the upper end of its capacity range. However, always size the heater correctly to the room for optimal performance.
💰 Running Costs
Energy Rate Used: £0.277/kWh — Ofgem Price Cap, Q1 2026 (January–March 2026, UK average, Direct Debit, inclusive of VAT)
| Usage Level | Sessions/Week | Approx. Hours/Year | Annual Cost |
|---|---|---|---|
| 🏠 Light Use | 2 | 150 | £374 |
| 🏠 Regular Use | 4 | 300 | £748 |
| 🧖 Heavy Use | 6 | 450 | £1,121 |
Calculation Formula:
Annual Cost = Power (kW) × Hours per Year × Unit Rate (£/kWh)
Example (9 kW heater, Regular Use):
9 kW × 300 hours × £0.277 = £748.00 per year
Per session cost (1.5-hour session):
9 kW × 1.5 hours × £0.277 = £3.74 per session
💡 The Glow Corner’s large 50 kg stone mass acts as a thermal reservoir, retaining heat effectively and reducing the frequency of active heating cycles during a session. This can mean actual energy consumption is lower than the theoretical maximum.
🛠️ Installation Requirements
Electrical Requirements:
| Requirement | 400V 3N~ (Three-Phase) | 230V 1N~ (Single-Phase) |
|---|---|---|
| Voltage | 400V 3N~ | 230V 1N~ |
| Fuse Rating | 3 × 16 A | 1 × 40 A |
| Supply Cable | 5 × 2.5 mm² | 3 × 10 mm² |
| Dedicated Circuit | Required | Required |
Minimum Safety Clearances:
| Position | Distance |
|---|---|
| Front (combustible and non-combustible materials) | 100 mm |
| Side walls (combustible and non-combustible materials) | 100 mm |
| Ceiling | 800 mm |
| Floor | 20 mm |
| Minimum room height | 2,000 mm |
Corner Installation Notes:
- The TRC90 is designed specifically for corner installation — the triangular profile sits flush against two adjoining walls.
- Ensure 100 mm clearance from both adjacent walls.
- The heater stands on the floor; Harvia adjustable feet are available separately for levelling on uneven surfaces.
Ventilation:
- Fresh air intake and exhaust venting must be provided in accordance with the installation manual.
⚠️ IMPORTANT: Installation must be carried out by a qualified electrician in accordance with BS 7671 (IET Wiring Regulations) and local building codes. At 9 kW, three-phase supply (400V 3N~) is recommended for optimal cable sizing and circuit breaker requirements.
🔒 Safety Features and Certifications
Built-in Safety:
- ✅ Overheat protection — permanently cuts power if temperature exceeds safe limits; manual reset required after resolving the cause
- ✅ Integrated thermostat sensor — operates independently of stone placement for stable, reliable temperature control
- ✅ Built-in timer with automatic shutoff — prevents accidental prolonged operation
- ✅ Internal tunnel design — supports heating elements independently from the stone load, maintaining safe airflow even as stones naturally deteriorate
Certifications:
- ✅ CE Marked — European conformity
- ✅ EAC Certified — Eurasian conformity
- ✅ IPX4 Rated — protected against water splashes from all directions
📍 Ideal Applications
| Application | Room Size | Notes |
|---|---|---|
| 🏠 Family Home Sauna | 8–14 m³ | Striking corner installation for dedicated indoor sauna rooms seating 4–6 people |
| 🛖 Garden Sauna Cabin | 8–11 m³ | Impressive pillar heater for well-insulated outdoor cabins (add 25–30% volume adjustment) |
| 🪵 Large Barrel Sauna | 8–10 m³ | Powerful corner option for larger barrel designs with corner space available |
| 🧖 Private Spa / Wellness Room | 8–14 m³ | 50 kg stone mass creates a luxurious, long-lasting steam experience |
| 🏋️ Home Gym Recovery Sauna | 8–14 m³ | Rapid stone reheat means the sauna is ready again quickly between users |
💡 The Glow Corner TRC90 is classified by Harvia for household use. For high-traffic commercial environments, consider a heater from Harvia’s commercial range (Senator, Club, or Virta).
♨️ Sauna Stones
- Stone Capacity: 50 kg
- Recommended Stone Size: Ø 5–10 cm diameter
- Stones Included: No — stones must be purchased separately
- Recommended Type: Olivine diabase, peridotite, or vulcanite (natural sauna stones designed for high heat and water contact)
- Replacement Frequency: Inspect annually; replace every 1–2 years with regular use
Stone Loading Tips:
- Heating elements must be completely covered by stones
- Place stones loosely to allow adequate airflow between them — the integrated internal tunnel assists with this
- Do not force oversized stones into the stone cavity
- Remove any broken or disintegrated stone fragments during inspections
- The thermostat is unaffected by stone placement thanks to Harvia’s integrated sensor design, but proper loading ensures optimal heat distribution
💡 The Glow Corner’s 50 kg capacity means you will need a substantial quantity of quality sauna stones. Ensure you purchase stones rated for sauna use — standard garden stones or river pebbles are not suitable and may crack or explode under heat.
🔧 Control System and Accessories
Built-In Control System: The TRC90 includes built-in manual timer and thermostat switches at the front base of the heater. No separate control panel is required.
| Control Feature | Details |
|---|---|
| Timer | Manual rotary timer |
| Thermostat | Manual temperature adjustment |
| Location | Front base of heater |
| Remote / WiFi Control | Not available on this model |
Compatible Accessories:
- Safety railing / guard rail (sold separately — recommended for family saunas with children)
- Harvia adjustable feet for floor levelling (sold separately)
- Sauna stones Ø 5–10 cm (sold separately — 50 kg required)
Included in the Box:
- Glow Corner TRC90 heater unit
- Installation and operating instructions
💡 If you require digital or WiFi control, the Glow Corner is also available in the TRC90XE variant with Xenio XE digital controls, or the TRC90E variant for use with a separate Harvia control unit.
❓ Frequently Asked Questions
Q: What size room will this heater work for? A: The Harvia Glow Corner TRC90 is designed for sauna rooms between 8 and 14 m³. If your room has glass doors, windows, or uninsulated walls, add 25–50% to your volume calculation to determine effective room size.
Q: How long does it take to heat up? A: Approximately 60 minutes to reach bathing temperature (65–80°C) in a properly insulated sauna room. The large 50 kg stone mass takes slightly longer to fully heat through, but once hot, it provides excellent heat retention and rapid steam recovery.
Q: What electrical supply do I need? A: The TRC90 can operate on 400V three-phase (3 × 16A fuses, 5 × 2.5 mm² cable) or 230V single-phase (1 × 40A fuse, 3 × 10 mm² cable). Three-phase supply is strongly recommended for a 9 kW heater. A dedicated circuit and professional installation by a qualified electrician are required.
Q: Does this heater have to go in a corner? A: Yes. The Glow Corner has a triangular profile specifically designed for corner installation. If you need a freestanding pillar heater for a non-corner position, consider the standard Harvia Glow range.
Q: Are sauna stones included? A: No, stones must be purchased separately. The TRC90 holds up to 50 kg of sauna stones, sized Ø 5–10 cm. High-quality olivine diabase or vulcanite stones are recommended.
Q: How much stone do I need to buy? A: The heater requires 50 kg of sauna stones (Ø 5–10 cm). It is advisable to purchase slightly more than 50 kg so you can select the best-fitting stones and have replacements available for future maintenance.
Q: Is a safety railing included? A: No, the safety railing is sold separately. A safety guard is recommended, particularly in family saunas where children may be present.
Q: What is the warranty? A: Harvia provides a 1-year warranty on heating elements and a 5-year warranty on other components. Contact Parts4Tubs for full warranty terms and conditions.
Q: Can I install this heater outdoors? A: The TRC90 is rated for interior wet-area use only. It can be installed inside a well-insulated outdoor sauna cabin, but the heater itself must be protected from direct weather exposure.
Q: Can I pour water on the stones? A: Yes — this is what the Glow Corner is designed for. Pour water onto the top of the stone pillar for a sharp, intense steam, or onto the exposed stone sides through the lattice casing for softer, gentler löyly. The open design gives you full control over your steam experience.
📑 Downloads and Resources
📄 Product Datasheet — Glow Corner TRC90 Steel (HTRC900400) — Full specifications and dimensions
⭐ Why Choose the Harvia Glow Corner TRC90
✅ Impressive 50 kg Stone Capacity — More than double the stone load of standard wall-mounted heaters, delivering softer steam, better heat retention, and a more authentic Finnish sauna experience.
✅ Space-Saving Corner Design — The triangular pillar profile transforms an unused corner into the visual centrepiece of your sauna, without sacrificing floor space.
✅ Controllable Steam Experience — Exposed stone surfaces through the lattice exterior let you choose between soft side-pour steam and intense top-pour blasts.
✅ Stable, Reliable Performance — Harvia’s patented integrated sensor ensures the thermostat operates independently of stone placement, with rapid reheat response when stones cool down.
✅ Finnish Engineering Heritage — Designed and manufactured by Harvia in Muurame, Finland, with over 75 years of sauna expertise.
✅ Certified and Safe — CE marked, EAC certified, IPX4 rated, with built-in overheat protection and automatic timer shutoff.
🇬🇧 Why Buy from Parts4Tubs
✅ UK-based company with dedicated local support
✅ Fast UK delivery on stocked items
✅ Expert advice from sauna and wellness specialists
✅ Competitive pricing on genuine Harvia products
✅ Full manufacturer warranty support
✅ Easy returns within 30 days
✨ Summary
The Harvia Glow Corner TRC90 brings 9 kW of Finnish-engineered pillar heating to your sauna corner, with a commanding 50 kg stone capacity that delivers soft, controllable steam and outstanding heat retention. Its triangular corner-mounted design saves floor space while creating a striking visual centrepiece, and the built-in manual timer and thermostat make operation effortless. With Harvia’s patented integrated sensor technology for stable long-term performance, CE certification, IPX4 rating, and robust steel construction, the Glow Corner is built for sauna enthusiasts who value both aesthetics and authentic bathing performance. Order from Parts4Tubs today for fast UK delivery and expert support.