Wiring a thermostat to your van's heating system controls the temperature automatically. Here is the wiring guide for the most common setups.
Verdict
For a diesel heater: wire a mechanical thermostat in series with the ignition wire (£15, 10 minutes). For Propex: use the dedicated DTS thermostat. For electric: use a plug-in thermostat (£15, no wiring). The thermostat pays for itself in fuel savings within 3 months.
Why You Need a Thermostat
Without a thermostat, your heater runs at full power until you manually turn it off. The van gets too hot, then too cold. A thermostat cycles the heater to maintain a set temperature. It saves fuel (gas or diesel) and keeps you comfortable.
Diesel Heater Thermostat Wiring
Most Chinese diesel heaters come with a wired controller that includes a thermostat sensor. If you want a separate thermostat:
- The thermostat connects between the heater's 12v power supply and the heater unit
- Wire the thermostat's NO (normally open) terminal in series with the heater's ignition wire
- Set the thermostat to the desired temperature (18°C is comfortable for most van sleepers)
- The heater turns on when the temperature drops below the set point and off when it reaches it Wiring diagram:
Battery (+) → 20A fuse → Thermostat (NO/COM) → Heater controller (12v input)
Propex / Gas Heater Thermostat
Propex heaters (HS2000, HS2800) are designed for wired thermostats. The Propex thermostat is a simple two-wire connection:
- Run a two-core cable from the heater to the thermostat location
- Connect one core to terminal "T1" on the heater PCB
- Connect the other core to terminal "T2"
- Mount the thermostat at head height (1.5m), away from drafts Digital thermostats (like the Propex DTS) are wired the same way but need a 12v feed (included in the wiring loom).
Electric Thermostat (EHU Backup)
For electric fan heaters and oil-filled radiators on EHU, use a plug-in thermostat (also called a "timer thermostat"). It plugs into the 230v socket, and the heater plugs into it. No wiring required. Set the temperature and forget it. Best: The Brentwood plug-in thermostat (£15, Screwfix). 2,300W max, digital display, programmable 7-day timer.
Thermostat Placement
The thermostat location matters:
- Too close to the heater: The thermostat reads the heat from the heater, not the van. The heater cycles on and off while the rear of the van stays cold.
- Too close to a window: Drafts trigger false cold readings. The heater runs constantly.
- Behind a curtain or door: The thermostat reads the microclimate, not the van. Best location: On the cab-side wall (furthest from the heater), at seat height (0.8m). This measures the average van temperature.
Common Thermostats
| Thermostat | Type | Voltage | Price | Works With |
|---|---|---|---|---|
| Propex DTS | Digital, wired | 12v | £45 | Propex heaters |
| Chinese diesel heater remote | Digital, wireless | 12v | £15 | Chinese diesel heaters |
| Honeywell DT90 | Mechanical, wired | 24-240v | £25 | Electric systems |
| Plug-in electric | Digital, 13A socket | 230v | £15 | Fan heaters, oil radiators |
| Nest/Eve (smart) | WiFi | 24v / battery | £80+ | Overkill for vans but works |
