This is a list of what type of heater was fitted when the vehicles were delivered, where known. The information is taken from the BR33003 series of driving instruction booklets.
| Class | Manufacturer | Type |
|---|---|---|
| Derby Lighweight |
Smiths | - |
| Met-Camm Lightweight | Smiths | - |
| 100 | Smiths | - |
| 101 | Smiths | - |
| 103 | Smiths | - |
| 104 | Smiths | - |
| 105 | Smiths | - |
| 107 | Smiths | - |
| 108 | Smiths | - |
| 109 | Smiths | - |
| 111 | Smiths | 2 off, each 40,000 BTU |
| 112 | Smiths | IIB/R |
| 113 | Smiths | IIB/R |
| 116 | Smiths | - |
| 125 | Smiths | IIB |
| 126 | Smiths | - |
| 127 | Smiths | IIB/R |
| AC Cars Railbus | Smiths | - |
| BCV/ECW Railbus | Smiths | - |
| Park Royal Railbus | Smiths | - |
| Wickham Railbus | Smiths | - |
| Wickham Elliot Railbus | Smiths | - |
| WMD Railbus | Drieha | W604 (hot water heater connected to the diesel engine cooling system) |