Micro-CHP (mCHP) is the small scale generation of heat and electricity simultaneously, from a single energy source, in individual homes or buildings. The initial success has been based on the deployment of internal combustion engine (ICE), with most mCHP units running on natural gas. Units are operable on a wide variety of fuels such as natural gas, diesel, kerosene, LPG, fuel oil and also on bio fuels. The niche mCHP markets are currently showing steady growth in Europe, but the overall opportunity in Europe is high. Over 5 million conventional boilers are sold annually that can be replaced with mCHP units. The choice of the type of technology depends on the heat to power ratio. Stirling engine based mCHP and ICE produce lesser electricity in comparison to fuel cells. The heat to power ratio is one differentiator, while others include cost, size, weight, noise, reliability, lifetime, operating hours, payback and how quickly the system can modulate, start-up or shut down.