♨️ Harvia Senator 10.5kW Sauna Heater – 9-15 m³ Capacity

Finnish engineering meets powerful performance for extended sauna sessions and soft, luxurious steam.

📋 Product Overview

The Harvia Senator 10.5kW is a premium floor-mounted electric sauna heater engineered for those who truly appreciate the art of sauna bathing. With its generous 40kg stone capacity and six powerful heating elements, this heater delivers the gentle, even warmth and soft steam that transforms an ordinary sauna session into an exceptional experience.

Crafted almost entirely from stainless steel, the Senator combines Finnish quality craftsmanship with robust durability, making it equally suited for family saunas, shared residential facilities, or smaller commercial applications such as boutique hotels and fitness centres.

This heater operates with a separate control unit (sold separately), providing flexible installation options and convenient temperature management. The Senator T10.5 represents Harvia’s commitment to creating heaters that serve sauna enthusiasts who value longer bathing sessions and consistent, quality steam.

⭐ Key Features

✅ 10.5kW Power Output – Delivers rapid, efficient heating for sauna rooms between 9-15 m³

✅ Six Heating Elements – Ensures even heat distribution and consistent temperature throughout your sauna session

✅ 40kg Stone Capacity – Large stone chamber creates soft, gentle steam ideal for extended relaxation

✅ Stainless Steel Construction – Premium corrosion-resistant materials built for years of reliable performance

✅ Floor-Mounted Design – Stable, secure installation with four adjustable feet for uneven surfaces

✅ Separate Control Unit Compatible – Works with Harvia C150, Griffin, Fenix, and Xenio control systems for flexible operation

✅ Commercial-Grade Durability – Robust build quality suitable for family saunas and smaller commercial facilities

✅ Finnish Quality – Designed and engineered by Harvia, a global leader in sauna technology since 1950

✅ CE Certified – Meets all European safety and compliance standards

⚙️ Technical Specifications

Specification	Value
Model Number	HSE105400 / T10.5
Power Rating	10.5 kW
Voltage	400V 3-phase (3N~)
Fuse Size	3 × 16 A
Connection Cable	5 × 2.5 mm²
Room Capacity	9 – 15 m³
Dimensions (W × D × H)	465 × 345 × 660 mm
Weight	25 kg
Stone Capacity	40 kg
Recommended Stone Size	Ø 5-10 cm
Minimum Room Height	1900 mm
Number of Elements	6
Mounting	Floor-mounted
Control System	External (sold separately)
Certifications	CE Marked
Warranty	2 years (domestic) / 1 year (shared residential) / 3 months (commercial)

 Room Sizing Guide

Basic Formula:

1 kW ≈ 1 - 1.5 m³ sauna room volume

Adjustment Factors:

Condition	Adjustment
Glass door/windows	+1.2 m³ per m² of glass
Uninsulated/log walls	+50% to calculated volume
Outdoor/barrel sauna	+25-30% to calculated volume
High ceiling (>2.3m)	Calculate additional volume

Worked Example:

📍 Example Room: 2.2m × 2.0m × 2.1m
- Base volume: 9.24 m³
- Glass door (0.8m × 2m = 1.6 m²): +1.92 m³
- Total calculated: 11.16 m³
- This 10.5 kW heater: ✅ Suitable for 9-15 m³
- Result: Perfect match for this sauna size

💡 Tip: For well-insulated saunas with proper vapour barriers and minimal glass, the Senator 10.5kW comfortably heats rooms at the upper end of its 15 m³ capacity. For log-walled or outdoor installations, consider sizing down to account for increased heat loss.

💷 Running Costs

Energy Rate Used: £0.2635/kWh (UK Ofgem Price Cap, October-December 2025)

Annual Cost Calculation:

Usage Level	Sessions/Week	Hours/Year	Annual Cost
🏠 Light Use	2	150	£415
🏠 Regular Use	4	300	£830
🧖 Heavy Use	6	450	£1,245

Calculation Formula:

Annual Cost = kW × Hours/Year × £0.2635

Example (10.5 kW heater, Regular Use):
10.5 kW × 300 hours × £0.2635 = £830.03

Per session cost (1.5 hour session):
10.5 kW × 1.5 hours × £0.2635 = £4.15 per session

⚠️ Actual costs depend on usage patterns, session length, insulation quality, and current energy rates. Rates are subject to quarterly Ofgem price cap adjustments.

🔌 Installation Requirements

Electrical Requirements:

Requirement	Specification
Voltage	400V 3-phase (3N~)
Fuse Size	3 × 16 A
Connection Cable	5 × 2.5 mm² (H07RN-F or equivalent rubber cable)
Sensor Cable	4 × 0.25 mm²
Dedicated Circuit	Required
IP Rating	Splash-proof junction box required

Minimum Clearances:

Position	Distance
Side walls (non-combustible)	150 mm minimum
Side walls (combustible)	180 mm minimum
Rear wall	50 mm minimum
Ceiling	1250 mm minimum
Front clearance	100 mm minimum
Bench distance	650 mm maximum from heater

Ventilation Requirements:

• Fresh air intake: Position above heater, minimum 500mm height, 50-100mm diameter
• Exhaust vent: Opposite wall from heater, near floor level
• Air exchange: 6 times per hour recommended
• Mechanical ventilation: Recommended for optimal performance

⚠️ IMPORTANT: Installation must be carried out by a qualified electrician 
in accordance with BS 7671 (IET Wiring Regulations) and local building codes.
PVC-insulated cables must NOT be used for heater connections due to heat 
sensitivity. Use H07RN-F rubber cable or equivalent only.

🔒 Safety Features & Certifications

Built-in Safety:

✅ Thermal cut-out protection with automatic reset

✅ Overheat protection limiter in sensor box

✅ Temperature sensor for precise control

✅ Stainless steel construction resists corrosion and maintains structural integrity

✅ Stable floor-mounted design with adjustable feet

Certifications:

✅ CE Marked – Full European conformity

✅ Manufactured to EN 60335-2-53 sauna heater standard

Control Unit Compatibility:

• Harvia C150 (2.3-17kW)
• Harvia C150VKK (communal use only)
• Harvia C260VKK (communal use only)
• Harvia Griffin
• Harvia Fenix
• Harvia Xenio CX170

🎯 Ideal Applications

Application	Room Size	Typical Capacity	Notes
🏠 Family Sauna	9-12 m³	2-4 people	Perfect for residential installations
🏡 Garden Sauna	9-15 m³	3-5 people	Account for outdoor heat loss
🏢 Terraced House Shared	10-15 m³	4-6 people	Ideal for building communal facilities
🏨 Boutique Hotel	10-15 m³	4-6 people	Commercial-grade durability
🏋️ Small Gym Sauna	10-15 m³	4-6 people	Robust construction for frequent use
🧖 Wellness Centre	10-15 m³	4-6 people	Professional performance

🪨 Sauna Stones

Stone Specifications:

• Stone Capacity: 40 kg
• Recommended Stone Size: Ø 5-10 cm diameter
• Stones Included: No (sold separately)
• Recommended Type: Olivine diabase, vulcanite, or quality granite sauna stones

Stone Installation Guidelines:

• Wash stones before installation to remove dust
• Place stones loosely between heating elements – do not wedge
• Stones must not rest on heating elements
• Ensure stones completely cover elements without forming high piles
• Re-stack stones at least annually (more frequently with heavy use)
• Replace crumbled or damaged stones promptly

⚠️ Using inappropriate stones (porous ceramics, soft soapstone) may damage heating elements and void warranty.

🎛️ Control Options & Accessories

Control System:

This heater requires a separate external control unit (not included). The control panel mounts outside the sauna room in a dry location at approximately 170cm height.

Compatible Control Units:

Model	Features	Suitable For
Harvia C150	Digital, timer, thermostat	Family/light commercial
Harvia Griffin	Advanced digital, WiFi ready	Premium residential
Harvia Fenix	Full digital control	Premium residential
Harvia Xenio CX170	Digital, black finish	Modern installations
Harvia C150VKK	Coin timer	Communal saunas

Recommended Accessories:

• Safety rail/guard (recommended for family use)
• Sauna stones (40kg required)
• Temperature/humidity meter
• Sauna bucket and ladle

❓ Frequently Asked Questions

Q: What size room will this heater work for? A: The Senator 10.5kW is suitable for sauna rooms between 9 and 15 m³. For rooms with glass doors, uninsulated walls, or log construction, add 25-50% to your volume calculation when sizing.

Q: How long does it take to heat up? A: A well-insulated sauna room typically reaches bathing temperature (65-80°C) within approximately 60 minutes. Heat-up time varies based on room size, insulation quality, and starting temperature.

Q: What electrical supply do I need? A: This heater requires a 400V three-phase supply with a 3 × 16A dedicated circuit. Professional installation by a qualified electrician is mandatory. This is not suitable for standard domestic single-phase supplies.

Q: Are sauna stones included? A: No, stones are sold separately. You will need 40kg of quality sauna stones with diameter between 5-10cm. We recommend olivine diabase or similar approved sauna stones.

Q: What is the warranty? A: Warranty periods are: 2 years for family/domestic use, 1 year for shared residential saunas (apartment buildings), and 3 months for commercial/institutional use. Contact Parts4Tubs for full warranty terms.

Q: Can I install this outdoors? A: This heater is designed for indoor sauna rooms. For outdoor installations (garden saunas, barrel saunas), ensure the heater remains protected within the sauna structure and account for increased heat loss when sizing.

Q: Do I need a control unit? A: Yes, the Senator T10.5 requires a separate external control unit (sold separately). Compatible options include the Harvia C150, Griffin, Fenix, and Xenio series.

📥 Downloads & Resources

📄 Installation Manual – Complete installation guide with wiring diagrams and safety distances

📄 Product Brochure – Harvia electric heaters range brochure

🏆 Why Choose the Harvia Senator 10.5kW

✅ Trusted Finnish Heritage – Harvia has been crafting sauna heaters since 1950, with over 200,000 heaters sold annually worldwide

✅ Premium Stainless Steel Build – Exceptional corrosion resistance for lasting performance

✅ Soft, Luxurious Steam – Six elements and 40kg stone capacity create the perfect löyly experience

✅ Versatile Application – Equally suited for home, shared residential, and light commercial use

✅ Proven Reliability – Commercial-grade construction trusted by hotels and fitness centres

✅ Energy Efficient Design – Heats rooms to optimal temperature within approximately one hour

🤝 Why Buy from Parts4Tubs

✅ UK-based company with dedicated local support

✅ Fast UK delivery

✅ Expert advice from sauna specialists

✅ Competitive pricing

✅ Full warranty support

✅ Easy returns within 30 days

✨ Summary

The Harvia Senator 10.5kW delivers exceptional Finnish sauna performance for rooms between 9-15 m³. With its robust stainless steel construction, generous 40kg stone capacity, and six heating elements, this floor-mounted heater produces the soft, even steam essential for a truly relaxing sauna experience. Ideal for family saunas, shared residential facilities, or smaller commercial applications, the Senator combines proven Harvia reliability with commercial-grade durability. Backed by comprehensive warranty coverage and Parts4Tubs expert support, order today for fast UK delivery.