Hydronic diesel hot water and air heating systems for your caravan, RV or boat
The unique DH Hydronic Series provides fast diesel hot water and optional air heating in the coldest of conditions. Designed and assembled in Tasmania by Dieselheat, these systems eliminate the hassles, risks (in boats) and costs of LPG. The DH Hydronic Series includes systems in 3 sizes to suit all situations (the DH9, DH15 and DH30). If you’re camping, sailing or living off-the-grid, take advantage of these systems to enjoy the benefits of hot water and air heating from one compact setup.
How do DH hydronic hot water systems work?
DH hydronic systems use a diesel furnace to heat coolant, which is then circulated to produce hot water through a heat exchanger. This coolant can also be routed to fan heads for air heating, making DH hydronic systems a versatile, hybrid solution for both hot water and air heating needs.
What’s different about the DH hydronic series?
Here are some of the key features that set these systems apart.
- All 316 stainless steel: Suitable for RVs and boats.
- Premium German-made Eberspacher furnaces: Quiet and reliable.
- Insulated tanks (DH15 and DH30): Retain heat for efficient operation.
- Fast heat up time: From 7 minutes to the first hot water (DH9).
- High flow rates: Short-term high flow rates to fill a sink or bucket.
- Fast reheat: Allows many people to have a shower with only a short time in between.
- Flexible installation: Compact size and separate fan heads allow for installation in tight spaces.
- Integrated air heating (optional): Enhances comfort.
- Watermark approved: Meets regulatory requirements and ensures hot water is always delivered at safe temperatures.
Why should I choose diesel instead of a gas heater or hot water system for my caravan, RV or boat?
- Single fuel type: Using a diesel or diesel electric installation, life is simpler with only one fuel to manage.
- Very safe: Certified installers are not required.
- Faster heat up times: From 7 minutes to first hot water, diesel is quicker than gas storage.
- Low flow rate capability: Provides hot water at very low flow rates (e.g., for washing dishes), unlike instant gas systems.
- Immediate hot water: The first drop of water is hot. With instant gas systems, cold water must flow while the system starts up.
- Ideal for marine use: Perfect for boats where gas hot water is not suitable.
For more information on going gasless please see here.
Which DH hydronic system is best for my caravan, RV or boat?
To help you decide, we’ve outlined the key differences between our 3 systems.
System
DH9 Hydronic
DH15 Hydronic
DH30 Hydronic
Description
Super compact, either modular kit or pre-assembled. Super fast heat up.
Compact, pre-assembled. Fast heat up.
Larger, pre-assembled. Provides more hot water.
Recommended uses
Slide on campers, camper trailers, small motorhomes (e.g., Transporter, Sprinter)
Caravans, off-road trucks, larger motorhomes, small boats
Large motorhomes, buses, off-grid houses
Furnace Options
Eberspacher D5E
Eberspacher D5E
Eberspacher D5E
Hydronic air heating compatible
Yes
Yes
Yes
Insulated tank
No
Yes – 10mm fibreglass
Yes – 10mm fibreglass
Shipped as
Modular kit or pre-assembled
Pre-assembled
Pre-assembled
Time to first usable hot water (from cold start)*
7 mins
9 mins
15 mins
Time to fully heated*
9 mins
14 mins
26 mins
Reheat time between showers*
4 mins
7 mins
15 mins
Time that flow rates can be supported at 30°C*
2L/min –>15 min
3L/min – 9 min
4L/min – 3.5 min
5L/min – 2 min
2L/min –>15 min
3L/min – 13 min
4L/min – 6 min
5L/min – 3 min
2L/min –>15 min
3L/min –>15 min
4L/min – 12 min
5L/min – 7 min
6L/min – 5 min
Long-term ‘indefinite’ flow rate*
2L/min at rise of 30°C
2L/min at rise of 30°C
2L/min at rise of 30°C
Recommended shower head
Bricor Ultra Max
Bricor Ultra Max
Bricor Elite
Bricor Elite
Recommended shower head flow rate
2.5L/min – 3.5L/min
2.5L/min – 4.5L/min
Up to 6L/min
Storage medium
Coolant 9L
Coolant 15L
Coolant 30L
Required space (mm)
300W x 280H x 280D
(assembled unit)
450W x 320H x 340D
630W x 320H x 380D
Approx. dry weight
13kg
20kg
25kg
Tank construction
316 stainless steel
316 stainless steel inner and outer
316 stainless steel inner and outer
*All values are based on average ambient temperatures. Actual results will vary depending on specific conditions.
Furnace information
Furnace
Eberspacher D5E
Recommended use
Combined hot water and air heating where air heating is needed overnight or where a longer duty cycle is needed. For extended touring or live-on-board situations.
Output
1.3kW to 5kW (stepless)
Manufacture location
Europe
Noise levels
Quietest option available due to better design and output modulation
Reliability / service intervals*
Best in class
3000h+ service interval
Fan motor
Brushless
*Service intervals are based on manufacturers’ guides or our experience. They can vary significantly depending on fuel quality, dust ingress, and how furnaces are used.
How do DH hydronic systems heat both air and water?
By adding an air heating head to your DH Hydronic Series diesel hot water system, you can turn it into an efficient air heater. It can deliver up to 5kW of heating through either Kalori or Dieselheat’s own ducted fan heads. These fan heaters can be installed remotely, offering flexibility in positioning for zone control and excellent heat distribution. Perfect for setups in caravans, RVs, or boats, this system provides an all in one combo for hot water and air.
Air Heating Thermostat
The Dieselheat Hydronic Thermostat pulls the hot water and air heating system together to act as one unit. It performs the following functions:
- System control: Switches hot water on/off.
- Air heater control: 3 manual speeds and automatic mode to control room temperature.
- Coolant control: Switches hot coolant on/off with fan heater, to minimise excess heat when air heating is not needed.
Combo Systems
Check out the DH9 Duo or the DH15 Duo. These combo packages are set up with a DH Hydronic hot water system, ducted fan and thermostat in a ready-to-install plug-and-play package.
How can I avoid wasting water on my van or boat?
Pair the DH Hydronic with our Specialised Shower Accessories for super water-wise showers (as low as 2L/min) with digital temperature control. We highly recommended this for caravans or boats where water is limited.
Low Flow Shower Heads
US made Bricor low flow shower heads provide excellent spray patterns at low flow rates giving a decent feeling water wise shower.
Digital Temperature Control Valves
Digital mixing valves allow a specific shower temperature to be set without needing to adjust a hot and cold tap. These work well for single pipe outdoor showers and deck showers on boats.
Warranty and technical support
All products in our DH Hydronic Series are backed by a two-year warranty. Not only this, at Dieselheat we pride ourselves on our excellent service, and we’re only a phone call away if you need professional advice. You will enjoy piping hot water, warmth and a good night’s sleep knowing that if you need help, we’ve got your back.
Still unsure? We’re passionate about providing the best diesel solutions and would love to chat about which system would work best for you! You can contact us or see here for more product information.
