Diesel fired heaters are able to warm up the engine in few minutes.
Hydronic coolant heaters gradually raise the temperature of the engine's coolant, assuring even heating of the engine block. They enable generators to have "warm starts," which reduce engine stress and wear and reduce demand on the battery. Hydronic coolant heaters work independently of the engine, yet they tap into the fuel and power supplies of the engine. This approach eliminates the need for an external power or fuel source, which enables them to operate anywhere a generator could be located, Warm starts reduce engine stress and wear and reduce battery demand with a pre-heater you will have smooth starts every time.