Keeping a boat warm, especially during colder months, is essential for comfort and safety. Diesel heaters, both air and liquid types, offer efficient and reliable solutions for marine environments. This comprehensive guide explores how diesel heaters function. It describes their heat distribution systems, including warm air blower heater matrixes. The guide also covers the role of calorifiers in providing domestic hot water via diesel liquid heater systems.
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Diesel Air Heaters
How They Work
Diesel air heaters are compact units designed to burn diesel fuel to produce heat. A fan and duct system then distributes this heat through the boat’s interior. These heaters are known for their efficiency, simplicity, and relatively straightforward installation.
Components and Operation
- Combustion Chamber: Diesel fuel is ignited in a combustion chamber, which generates heat as the fuel burns.
- Heat Exchanger: The heat generated in the combustion chamber warms a heat exchanger. The function of the heat exchanger is to transfer the heat from the combustion process to the air.
- Air Circulation: A fan or blower forces air over the heat exchanger. As the air passes over the exchanger, it picks up the heat.
- Ductwork: The heated air is then pushed through ducts to different parts of the boat. The ductwork ensures that the warm air is distributed evenly throughout the vessel.
Advantages of Diesel Air Heaters
- Quick Heating: Diesel air heaters can quickly warm up space because the heat is immediately distributed.
- Fuel Efficiency: Modern diesel air heaters are highly efficient, optimizing fuel consumption to provide maximum heat with minimal waste.
- Compact Size: Diesel air heaters are relatively small. They can be installed in a variety of locations. This makes them versatile options for different boat sizes and layouts.
- Uncomplicated Set Up: Diesel air heater installations are straightforward and uncomplicated systems compared to central heating. There is no pipework to run. You don’t need to fit radiators. The overall installation process is much simpler. This makes it an efficient choice for heating.
Considerations for Diesel Air Heaters
While diesel air heaters have numerous advantages, there are a few considerations to keep in mind:
- Installation: Proper installation is crucial to ensure optimal performance and safety. This includes venting exhaust gases out of the boat.
- Maintenance: Regular maintenance is necessary to keep the heater in good working condition. This includes cleaning the combustion chamber and checking the fuel lines.
- Noise: Some models may produce noise from the fan and combustion process. Selecting a quieter model, like Wallas with ducting silencers, or soundproofing the installation area can help mitigate this issue.
- No Water Heating: Unlike diesel liquid heaters, air heaters are not suitable for heating domestic hot water on boats.
Diesel Liquid Heaters
How They Work
Diesel liquid heaters operate by burning diesel fuel to heat a liquid, typically a mixture of water and antifreeze. This heated liquid circulates through a central heating system to provide warmth to the boat’s interior. Diesel liquid heaters are versatile, as they can also be used to heat domestic hot water.
Components and Operation
- Combustion: Diesel fuel is burned in a combustion chamber to heat the liquid within a heat exchanger. The heated liquid is a coolant mixture, usually consisting of water and antifreeze.
- Circulation Pump: A pump circulates the heated liquid through pipes and hoses. These are connected to various radiators or blower boxes distributed throughout the boat.
- Warm Air Blower Heater Matrixes: Some diesel liquid heating systems include warm air blower boxes or heater matrixes. We will go into more detail about these below.
Advantages of Diesel Liquid Heaters
- Even Heat Distribution: Diesel liquid heating systems provide more uniform heat distribution, eliminating hot and cold spots within the boat.
- Versatility: These heaters can warm the boat’s interior. They also produce domestic hot water via a calorifier. This makes them a multifunctional heating solution. More details on calorifiers can be found towards the bottom of this page.
- Integration with Engine: Diesel liquid heaters can be integrated with the boat’s engine cooling system. This allows the system to utilize surplus engine heat to heat water.
- Silent Operation: Diesel liquid heaters are quieter than air heaters, as the heat is transferred through liquid circulation rather than forced air.
Considerations for Diesel Liquid Heaters
- Complex Installation: Diesel liquid heaters require more complex installation compared to air heaters. Proper installation includes setting up pipes, pumps, and heat exchangers.
- Space Requirements: These systems may require more space for components such as pipework and radiators.
- Maintenance: Regular maintenance is essential to ensure the system operates efficiently. This includes checking for leaks, ensuring the pump is functioning correctly, and replacing the coolant mixture as necessary.
Warm Air Blower Heater Matrixes
Understanding Warm Air Blower Heater Matrixes
Warm air blowers and heater matrixes are fitted to systems supplied by diesel liquid heaters. These blowers enhance the heat distribution system by using fans to blow air over a hot liquid-filled heat exchanger. They effectively convert the liquid’s heat into warm air and distribute it throughout the boat.
Operation
- Heated Liquid Supply: The heated liquid from the diesel liquid heater or engine flows through the blower heat exchanger.
- Heat Transfer: The heat exchanger, which is designed to maximize the surface area for heat transfer, becomes hot.
- Air Circulation: Fans blow air over the heat exchanger, picking up the heat.
- Warm Air Distribution: The warm air is then blown directly into the boat’s spaces.
Advantages and Considerations
- Enhanced Heat Distribution: Warm air blower heaters improve the overall heat distribution, ensuring that the boat’s interior is evenly warmed.
- Efficiency: By using the heated liquid efficiently, these blowers contribute to the overall energy efficiency of the heating system.
- Space Requirement: Integrating blower heater matrixes could require additional space for installation.
- Quiet Operation: Warm air blower boxes and fan heater matrixes operate much quieter than traditional air heaters. This makes them more suitable for a domestic environment and sleeping cabins
Calorifiers for Domestic Hot Water

Function of Calorifiers
Calorifiers are water heaters. They use heat from a diesel liquid heating system and/or engine. This heat is used to produce domestic hot water. This system uses indirect heating. The heating liquid does not mix with the domestic water. Instead, it transfers heat through a coil inside the calorifier.
Components and Operation
- Heating Coil: The heated liquid from the diesel liquid heater flows through a coil inside the calorifier tank. The coil acts as a heat exchanger.
- Indirect Heating: The coil transfers heat to the domestic water stored in the calorifier tank without mixing the two liquids.
- Hot Water Supply: The calorifier provides a steady supply of hot water. This is used in showers, sinks, and other domestic applications on the boat.
Advantages of Calorifiers
- Efficiency: Using the heat from the existing diesel liquid heating system or engine to produce hot water improves the system’s efficiency. This method enhances the overall efficiency.
- Reliable Supply: Calorifiers ensure a reliable supply of hot water, improving the comfort and convenience of life onboard. They are usually fitted with a 1kw immersion heater which can be used as a backup.
- Efficiency: Calorifiers seamlessly integrate with the diesel liquid heating system, maximizing the utility of the heat produced. The integrated immersion heater can heat the water with surplus solar energy in the summer. It can also heat the water when plugged into a shoreline supply.
Considerations for Calorifiers
- Space Requirement: Installing a calorifier requires space for the storage tank and additional piping.
- Professional Installation: The correct installation of calorifiers is crucial to ensure optimal performance and safe operation. If in doubt please contact us for professional advice.
Summary
Diesel Air Heaters
- Pros: Quick installation, rapid heating, independent operation, compact size.
- Cons: No provision for hot water production and potential noise issues.
Diesel Liquid Heaters
- Pros: Even heating and versatile use. Integration with engine cooling systems. Quieter operation because operating noise is kept away from living quarters through installation in the engine bay.
- Cons: More complex and space-consuming installation, dependency on a correct setup of circulation components, more involved maintenance routines.
Practical Tips for Boat Owners
- Assess Your Needs: Consider the size of your boat and typical weather conditions. Evaluate your specific heating and hot water requirements before choosing a heating system.
- Professional Installation: DIY installation is possible. However, hiring a professional ensures that the system is installed correctly. This leads to optimal performance and safety. Webasto and Autoterm offer extended warranties for installation by certified engineers. Contact us for details.
- Regular Maintenance: Adhere to regular maintenance schedules to keep the system functioning efficiently. This includes cleaning combustion chambers, checking fuel lines, and inspecting circulation components for leaks.
- Noise Considerations: If noise is a concern, choose quieter models or soundproof the areas where the heater is installed.
- Space Optimization: Plan the installation to use space efficiently, especially for components like calorifiers and circulation pipes.
Our Thoughts On Cheap Chinese Diesel Heaters
Choosing cheap Chinese diesel heaters can lead to significant issues in both safety and reliability. These heaters are often manufactured without adherence to acceptable safety standards, making them a risky option for any domestic environment. The components are typically subpar; thin wires and non-waterproof plugs expose users to potential electrical hazards, breakdowns and fires. Additionally, the pumps and fans used in these systems are prone to frequent breakdowns, leading to inconvenience and costly repairs. These heaters may serve as a temporary heating solution for minimally regulated spaces like garages. However, they lack durability, safety, and consistent performance. This makes them ill-suited for reliable residential use. Investing in higher-quality heating systems is crucial for ensuring safety and dependable warmth, particularly in domestic settings.
Conclusion
Choosing the right heating system for your boat is crucial for ensuring safety, comfort, and convenience in cold weather. Diesel air heaters offer quick and direct heating. Diesel liquid heaters provide versatile and quiet operation with even heat distribution. Warm air blower heater matrixes increase the efficiency and reach of liquid heating systems. Calorifiers provide the added advantage of domestic hot water production.
By understanding the workings, components, and advantages of these systems, boat owners can make informed decisions. This knowledge helps them choose what best meets their needs and conditions. Whether you prioritize rapid heating, quiet operation, or the multifunctional benefits of liquid heating, a diesel heater system will provide warmth. It will keep your boat habitable all year round.
For quotes and bookings contact us on 07846 274 926 or email marineheatingsolutions@gmail.com