Diesel Heat DH22 vs DH15: Which Hot Water & Heating System Suits Your Offroad Grit RV?
- admin996144
- Jun 11
- 2 min read

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.
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