The Webasto Thermo Pro 90 is a powerful and robust diesel water heater (hydronic) designed for larger marine vessels, such as Dutch barges, large cruisers, and commercial workboats. With a maximum heat output of 9.1 kW, it provides substantial capacity for complex heating circuits involving multiple radiators, fan matrices, and domestic hot water systems.
Webasto Thermo Pro 90: High-Capacity Hydronic Comfort
Engineered for durability and performance in extreme conditions, the Thermo Pro 90 features a stepless output adjustment (from 1.8 kW to 9.1 kW), ensuring it operates at the most efficient level to maintain your desired temperature. It is equipped with “Arctic Start” technology for rapid warm-up in freezing temperatures and automatic altitude adjustment (up to 3,500m), making it suitable for a wide range of geographic locations.
The system integrates seamlessly with SureCal calorifiers to provide an “infinite” supply of hot water and can support up to 6 radiators or multiple Silencio blower boxes for distributed cabin warmth.
Expert Installation and BSS Safety
Our OFTEC-trained engineers provide professional Webasto Thermo Pro 90 installations, ensuring all fuel, coolant, and exhaust connections meet strict marine safety standards. To ensure full Boat Safety Scheme (BSS) compliance, we utilise 38mm marine-grade exhaust systems with silencers and insulated hull fittings.
For detailed technical specifications, you can visit the Webasto Corporate Technical Portal or review the OFTEC consumer guide.
Free Installation Offer Winter 2025/2026
We are offering free installation for all diesel heater narrowboat kits between the 15th of November 2025 and the 15th of February 2026. See individual appliance listing for boat stove kit prices. Email us for details.
Webasto Thermo Pro 90 Heater Kit Includes:
| Webasto Thermo Pro 90 9 kW 12 Volt Diesel Water Heater |
| Water Circulation Pump |
| DP42 Fuel Pump |
| Webasto Controller with Timer |
| Fuel Pick-up Pipe |
| Marine Electrical harness c/w fuse holders and fuses |
| 1m Exhaust Pipe |
Webasto Thermo Pro 90 Narrowboat Kit:
Includes Webasto Boat Diesel Heater, Webasto Multi Control Timer, 2m Marine Exhaust, Exhaust Skin Fitting, Fuel Line Kit, Header Tank and Safety Certificate.
£2995.00 including free installation Winter 25/26
Webasto Thermo Pro 90 Heater Price:
£2200.00
Optional extras:
- Webasto Multi Control Timer – £110.00
- Webasto Room Thermostat – £115.00
- Webasto ThermoConnect TCON 2 – £349.00
- 2m Marine Exhaust Pipe 38mm – £135.00
- 38mm Exhaust Skin Fitting / Hull Fitting – £119.95
- Marine Fuel Filter With Stop Tap – £49.50
- Fuel Line Kit (Marine Fuel Filter, Valves, Copper Pipe, Clips, Fittings) – £225.00
- Header Tank For Diesel Heater £85.00
- Stainless Steel Coil Calorifier – Boat Hot Water Tank – Various Sizes
- Diesel Appliance Safety Certificate – £59.00