To determine which diesel hot water system best suits your needs, first decide whether a DH Hydronic or E-Solar system is the right choice. Both systems are built around the high-quality, German-made Eberspächer D5E diesel furnace, which delivers 5 kW of heat output and features:
- 32 power levels, so operates like and inverter
- Super quiet with soft restarts – ideal for overnight air heating
- 3000 hour service interval (best in class)
- Long lasting brushless motor
- German reliability.
Both systems can also support optional air heating and work very effectively as combo hot water and air heaters.
Key Differences in System Design
The main difference between the two systems lies in their overall design philosophy.
DH Hydronic
The DH Hydronic system is a hybrid on-demand system that behaves partly like an instant hot water system and partly like a storage system. It stores 9–30 litres of engine coolant in a stainless-steel tank. This coolant is heated by the diesel furnace and acts as a thermal “battery,” instantly heating fresh water as it passes through a built-in plate heat exchanger.
E-Solar
The E-Solar system is more like a traditional storage hot water system. It uses an insulated copper tank to store hot water, which can be heated using diesel, electricity, or (in marine installations) the vessel’s engine.
Operating Difference
A key operational difference is how hot water is accessed. The DH Hydronic system must be switched on to produce hot water whereas the E-Solar system stores hot water, so once heated, hot water remains available even after the system is switched off.
Feature Summary
DH Hydronic
- Hybrid between instant and storage system
- 9, 15 or 30L capacity
- Diesel only
- Must be switched on to produce hot water
E-Solar
- Storage hot water system
- 15, 22 or 40L capacity
- Diesel, 240V, 12V, or marine engine heating options
- Hot water remains available after switching off
Which System Type Should You Choose?
- Choose DH Hydronic if you have a caravan or RV, spend a lot of time off-grid, move frequently during the day, and want a compact, fast-heating system powered solely by diesel.
- Choose E-Solar if you live in your caravan full-time, spend extended periods in caravan parks with access to mains power, want solar hot water or live aboard a boat and want hot water available at all times without needing to switch the system on.
Choosing a System Size
Choosing the right system size involves balancing size and weight against the amount of hot water available for longer, higher-flow showers. Larger systems provide greater hot water capacity but take up more space and add weight, while smaller systems reheat faster but deliver less hot water in a single continuous use.
When selecting a system size, consider the available installation space, the weight-carrying capacity of your vehicle or RV, the expected shower flow rate, and the amount of water you will realistically have available for showering.
See below for typical application of our systems and don’t forget to read the more detailed information pages which contain more specific information on sizes, weights and performance.
DH Hydronic
- DH9 for Slide on campers, camper trailers, small motorhomes (e.g., Transporter, Sprinter)
- DH15 for Caravans, off-road trucks, larger motorhomes, small boats
- DH30 for Large motorhomes, buses, off-grid houses
DH E-Solar
- 15L Small motorhomes eg VW T6, off road trucks, small to medium boats.
- 22L Caravans, off-road trucks, motorhomes, medium boats.
- 40L Buses, off-grid houses, larger boats
For more information and details about these systems please view the DH Hydronic information page or the E-Solar Information page on our website, otherwise feel free to contact us for some expert advice on our systems.
