Compact water boilers are commonly used in small to medium size boats for heating and hot water. The most compact ones are also used to heat up the cabin of buses and heavy trucks or RVs in cold weather. This equipment is generally run on diesel, because electrical boilers are not so powerful or would need very high capacity batteries. The performance of current technologies is often between 75% and 90% the lower heating value of diesel. Our objective is to reach levels of up to 106% this value through blue efficiency: fuel burns at temperatures of around 1,560 C, and as the combustion is almost complete there is no soot generate (what reduces maintenance costs and keeps performance with use). The second objective is to make these diesel boilers hybrid (electric-diesel) and adaptable to biodiesel. Higher performance and hybrid technology mean fuel and maintenance savings for end users, and lower carbon, NO2, SOx and particles emission.