Diesel Heat DH22 vs DH15: Which Hot Water & Heating System Suits Your Offroad Grit RV?

Diesel Heat Australia DH22 Diesel / Electric Hot Water System

When you’re chasing red dirt tracks or setting up by the coast, comfort matters—and that means hot water and a warm van. Two of the best diesel-powered options available in Australia are the DH15 and the DH22 from Dieselheat. Both are compact, efficient systems that deliver hot water and (when fitted correctly) internal van heating.

At Offroad Grit, we go a step further: every van we build that options the DH15 or DH22 includes the hydronic fan head component—so you're not just heating water, you're heating your whole caravan.

Let’s break down the key differences.

DH15: Lightweight & Compact

Best for: Smaller caravans or those looking to save weight while still enjoying hot water and heating.

• Hot Water Tank: 10L copper

• Heating Method: Diesel via Eberspacher D5E HS3 furnace

• Power Draw: Approx. 0.1–0.2L/hr of diesel

• Air Heating: Yes (hydronic fan head included in Offroad Grit vans)

• Water Heating Time:

  • From cold to 60°C: ~22–30 minutes

  • Reheating (e.g., after a shower): ~10–15 minutes

Why choose the DH15?

• Compact design – easy to install in tighter builds

• Efficient on diesel

• Quieter operation

• Simpler setup with fewer components than larger systems
  

DH22: Powerful, Solar-Compatible, and Fast

Best for: Larger vans, long stays off-grid, and travellers with solar setups looking to reduce diesel use.

• Hot Water Tank: 22L SureCal copper with twin coils

• Heating Methods:

  • Diesel (Eberspacher D5E HS3)

  • Electric (12V, 24V, or 240V)

  • Solar power using surplus energy via solar diverter (not included)

• Power Draw: Approx. 0.2–0.3L/hr on diesel

• Air Heating: Yes (hydronic fan head included in Offroad Grit vans)

• Water Heating Time:

  • From cold to 60°C (on diesel): ~20 minutes

  • Reheating: ~8 minutes

Why choose the DH22?

• Dual fuel options = flexibility

• Integrates with solar to reduce fuel use

• Larger tank = more back-to-back hot showers

• Comes pre-assembled = easier install
  

📊 Side-by-Side Comparison

Feature	DH15	DH22
Heating Capacity	1.5kW	5kW
Tank Size	10L Copper	22L SureCal Copper (Twin Coils)
Heating Methods	Diesel Only	Diesel + Electric (12V/24V/240V) + Solar
Water Heat-Up Time	~22–30 min (cold) / ~10–15 min (reheat)	~20 min (cold) / ~8 min (reheat)
Air Heating	Yes (Hydronic)	Yes (Hydronic)
Fuel Consumption	~0.1–0.2L/hr	~0.2–0.3L/hr
Ideal For	Compact vans, moderate use	Larger vans, solar setups, full off-grid

🔧 What You Get in Every Offroad Grit Van

Whether you choose the DH15 or DH22, you can rest easy knowing:

✅ Every Offroad Grit build that options the DH15 or DH22 includes the internal fan heater—no extra add-ons needed.

✅ Seamless integration with your plumbing and electrics thanks to CNC-cut floors and smart design.

✅ Tested, proven systems for Australian off-road touring.

Final Word

If you’re a weekend warrior or weight-conscious traveller, the DH15 will suit you just fine. But if you want the freedom to use diesel, solar or shore power—and want faster heat-up times for longer hot showers—the DH22 is a standout.

Not sure which option fits your build best? Reach out—we’re here to help you build the ultimate off-grid caravan experience.