🌡️ Harvia The Wall SW45 4.5kW Black Steel Sauna Heater – 3-6 m³ Capacity

Minimalist Finnish Design Meets Powerful Performance for Compact Home Saunas

♨️ Product Overview

The Harvia The Wall SW45 Black Steel is a compact yet powerful 4.5kW electric sauna heater designed for home saunas between 3-6 cubic metres. Manufactured by Harvia, Finland’s leading sauna heater brand celebrating 75 years in 2025, this wall-mounted heater combines minimalistic Scandinavian design with practical functionality.

The distinctive black steel finish adds a contemporary touch to any sauna interior, whilst the illuminated control switches ensure safe, intuitive operation even in dimly lit environments. With ambidextrous installation options and the ability to integrate seamlessly into sauna benches, The Wall offers exceptional design flexibility.

Built for longevity, the heater features extra-long heating elements with dedicated support structures that prevent twisting and extend operational lifespan. The unique Harvia mounting bracket, included in every delivery, automatically establishes correct safety clearances—making installation straightforward for qualified electricians.

Ideal for residential bathroom saunas, garden room installations, and compact wellness spaces where space is at a premium but performance cannot be compromised.

✨ Key Features

✅ 4.5kW Power Output – Efficient heating for sauna rooms 3-6 m³, reaching optimal temperature in approximately 30-45 minutes

✅ Black Steel Finish – Contemporary matte black steel construction provides a modern aesthetic whilst ensuring durability and corrosion resistance

✅ Illuminated Control Switches – Built-in timer (1-4 hours) and thermostat with illuminated switches visible in low-light conditions for safe, easy adjustment

✅ Ambidextrous Installation – Designed for both left and right-handed configurations to suit any sauna layout

✅ Bench Integration Option – Compact dimensions allow the heater to be integrated within the sauna bench structure, maximising floor space

✅ 20kg Stone Capacity – Generous stone capacity ensures excellent thermal mass and authentic steam (löyly) production when water is applied

✅ Extra-Long Heating Elements – Supported by dedicated structures to prevent twisting, ensuring smooth heat transfer and extended service life

✅ Smart Air Circulation Design – Engineered airflow creates even temperature distribution throughout the sauna room for consistent warmth

✅ Included Mounting Bracket – The Harvia wall bracket sets minimum safety distances automatically, simplifying installation

✅ CE Certified & IPX4 Rated – Fully compliant with European safety standards and rated for wet area installation

🔧 Technical Specifications

Specification	Value
Model Number	HSW450400M
Type Code	SW45
Power Rating	4.5 kW
Room Capacity	3 – 6 m³
Voltage Options	230V 1N~, 230V 3~, 400V 3N~
Frequency	50/60 Hz
Fuse Size (230V 1N~)	25 A
Fuse Size (230V 3~)	3 × 16 A
Fuse Size (400V 3N~)	3 × 10 A
Supply Cable (230V 1N~)	3 × 2.5 mm²
Supply Cable (400V 3N~)	5 × 1.5 mm²
Dimensions (H × W × D)	610 × 430 × 260 mm
Net Weight	11.7 kg
Stone Capacity	20 kg
Stone Size	Ø 5-10 cm
Timer Range	1 – 4 hours
Control Type	Built-in illuminated switches
IP Rating	IPX4
Main Material	Steel (Black Steel finish)
Mounting	Wall-mounted, vertical
Certifications	CE, EAC

📐 Room Sizing Guide

Basic Formula: 1 kW heats approximately 1 – 1.5 m³ of well-insulated sauna space

Adjustment Factors:

Condition	Adjustment
Glass door/window	Add +1.5 m³ per m² of glass
Uninsulated log walls	Add +25-50% to calculated volume
Outdoor/garden sauna	Add +25-30% to calculated volume
High ceiling (above 2.3m)	Calculate additional volume accordingly

💡 Worked Example:

📍 Example Room: 1.5m × 1.5m × 2.0m

• Base volume: 4.5 m³
• Glass door (0.6m × 1.8m = 1.08 m²): +1.62 m³
• Total calculated: 6.12 m³
• The Wall SW45 4.5kW: ✅ Suitable – covers 3-6 m³

📍 Example Room: 1.8m × 1.6m × 2.1m

• Base volume: 6.05 m³
• Fully insulated, no glass
• Total calculated: 6.05 m³
• The Wall SW45 4.5kW: ⚠️ At upper limit – consider 6kW model for comfort margin

💷 Running Costs

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

Usage Level	Sessions/Week	Hours/Year	Annual Cost	Per Session
🏠 Light Use	2	150	£178	£1.19
🏠 Regular Use	3	225	£267	£1.19
🧖 Frequent Use	5	375	£445	£1.19

Calculation Formula:

Annual Cost = kW × Hours/Year × £0.2635

Example (4.5 kW heater, Regular Use - 3 sessions weekly):
4.5 kW × 225 hours × £0.2635 = £266.79

Per session cost (1.5 hour session):
4.5 kW × 1.5 hours × £0.2635 = £1.78 maximum
(Actual cost lower as heater cycles on/off to maintain temperature)

⚠️ Costs are estimates based on maximum power consumption. Actual running costs depend on room insulation, ambient temperature, session length, and current energy rates. The heater cycles to maintain temperature, so real consumption is typically 60-70% of maximum rating.

⚡ Installation Requirements

Electrical Requirements:

Requirement	230V Single Phase	400V Three Phase
Voltage	230V 1N~	400V 3N~
Fuse Size	25 A	3 × 10 A
Cable Size	3 × 2.5 mm²	5 × 1.5 mm²
Dedicated Circuit	Required	Required

Minimum Safety Clearances:

Position	Distance
Front (all materials)	20 mm
Left side	35 mm
Right side	35 mm
Ceiling	1200 mm
Floor	80 mm
Minimum room height	2000 mm

Ventilation Requirements:

• Fresh air intake near floor level, typically below or behind the heater
• Exhaust vent positioned on opposite wall, approximately 300mm below ceiling
• Refer to installation manual for specific requirements

Package Contents:

• The Wall SW45 electric heater
• Wall mounting bracket
• Hot air deflector
• Fastening kit
• Installation and operating instructions

⚠️ IMPORTANT: Installation must be carried out by a qualified electrician in accordance with BS 7671 (IET Wiring Regulations), manufacturer guidelines, and local building regulations. The heater must be connected to a dedicated circuit with appropriate RCD protection.

🛡️ Safety Features & Certifications

Built-in Safety:

• ✅ Automatic thermal cut-out protection
• ✅ Overheat protection sensor
• ✅ Timer auto-shutoff (maximum 4 hours)
• ✅ Protected heating elements with support structure
• ✅ Components positioned at base to protect from heat and moisture
• ✅ IPX4 splash-proof rating for wet environments

Certifications:

• ✅ CE Marked – European conformity
• ✅ EAC Certified – Eurasian conformity
• ✅ IPX4 Rated – Protection against water splashing

🎯 Ideal Applications

Application	Room Size	Capacity	Suitability
🏠 Bathroom Sauna	3-4 m³	1-2 people	✅ Excellent
🏠 Home Sauna Room	4-6 m³	2-3 people	✅ Excellent
🛖 Compact Garden Room	3-5 m³	2-3 people	✅ Good (add 25% volume)
🪵 Small Barrel Sauna	3-4 m³	2 people	✅ Good (verify volume)
🧖 Ensuite Wellness Space	3-5 m³	1-2 people	✅ Excellent

🪨 Sauna Stones

• Stone Capacity: 20 kg
• Recommended Stone Size: Ø 5-10 cm diameter
• Stones Included: No – sold separately
• Recommended Types: Olivine diabase, vulcanite, or Harvia genuine sauna stones
• Replacement Interval: Every 1-2 years with regular use (inspect annually)

💡 Tip: Arrange stones loosely to allow optimal air circulation through the heater. Avoid packing stones too tightly as this restricts airflow and reduces heating efficiency.

🎛️ Control Options

Built-in Controls:

• Timer: 1-4 hours with delay start capability
• Thermostat: Adjustable temperature control
• Illumination: Backlit switches for low-light visibility
• Position: Timer at top (frequently used), thermostat at bottom

WiFi/App Control: Not available on this model. For smart control functionality, consider the SW45E model with separate control unit compatible with Harvia WiFi modules.

Compatible Control Panels (for SW45E variant):

• Harvia C150 digital control unit
• Harvia Xenio digital control panel
• Harvia Griffin digital control panel

❓ Frequently Asked Questions

Q: What size room will this heater work for? A: The Wall SW45 4.5kW is designed for sauna rooms between 3 and 6 m³. For rooms with glass doors, windows, or uninsulated walls, add 25-50% to your volume calculation. If your calculated volume exceeds 6 m³, consider the 6kW or 8kW models.

Q: How long does it take to heat up? A: Typically 30-45 minutes to reach optimal sauna temperature (70-80°C), depending on room size, insulation quality, and ambient temperature. Smaller, well-insulated rooms heat faster.

Q: What electrical supply do I need? A: This heater can operate on 230V single-phase (25A fuse, 3×2.5mm² cable) or 400V three-phase (3×10A fuses, 5×1.5mm² cable). A dedicated circuit with RCD protection is mandatory. Always consult a qualified electrician.

Q: Are sauna stones included? A: No, sauna stones are sold separately. You will need 20kg of stones with Ø 5-10 cm diameter. We recommend Harvia genuine sauna stones or quality olivine diabase stones.

Q: Can I install this outdoors? A: The Wall SW45 is designed for indoor use in controlled environments. For outdoor garden saunas, ensure the sauna cabin itself provides adequate weather protection around the heater. The heater is not rated for direct outdoor exposure.

Q: What is the warranty? A: Harvia provides manufacturer warranty coverage. Contact Parts4Tubs for full warranty terms and conditions applicable to UK purchases.

Q: Can the heater be integrated into the bench? A: Yes, the compact design specifically allows for bench integration, providing more flexibility in sauna interior design. Ensure all safety clearances are maintained.

📥 Downloads & Resources

📄 Installation Manual EN – Complete installation guide with wiring diagrams

📄 Harvia Electric Heaters Brochure – Full product range information

🏆 Why Choose The Wall SW45 Black Steel

• ✅ Finnish Quality – Manufactured by Harvia, the world’s leading sauna heater brand with 75 years of expertise
• ✅ Space-Saving Design – Compact wall-mounted unit with bench integration capability maximises usable sauna space
• ✅ Modern Aesthetics – Black steel finish complements contemporary sauna interiors
• ✅ User-Friendly Operation – Illuminated controls for safe adjustment in low-light environments
• ✅ Flexible Installation – Left or right-handed mounting options suit any sauna layout
• ✅ Built to Last – Extra-long heating elements with dedicated supports extend operational lifespan
• ✅ Certified Safety – CE marked and IPX4 rated for peace of mind

🤝 Why Buy From Parts4Tubs

• ✅ UK-Based Company – Local support from Northamptonshire with genuine product expertise
• ✅ Fast UK Delivery – Prompt dispatch to mainland UK addresses
• ✅ Expert Advice – Sauna specialists available for sizing and technical questions
• ✅ Competitive Pricing – Great value on genuine Harvia products
• ✅ Full Warranty Support – UK warranty backing on all products
• ✅ Easy Returns – Hassle-free returns within 30 days

🔥 Summary

The Harvia The Wall SW45 4.5kW Black Steel sauna heater delivers efficient, reliable heating for compact saunas up to 6 m³. Featuring Finnish engineering excellence, a sleek black steel finish, and user-friendly illuminated controls, it’s the ideal choice for home bathroom saunas, small garden rooms, and contemporary wellness spaces. With built-in safety features, flexible installation options, and genuine Harvia quality backed by 75 years of expertise, this heater transforms any small space into an authentic sauna experience. Order today from Parts4Tubs for fast UK delivery and expert support.