Energy source

 Stored at very high pressure (7 times atmospheric temperature) and can be lit by an open flame as it has a low flash point temperature. This makes gas storage into a very real potential hazard. In addition it is more expensive to run than Liquid Fuel. Gas is 400 times lighter than liquid fuel which makes the boiler smaller and therefore 25% cheaper to install. However it is 80% more expensive to run.

 A heat pump draws its extra energy efficiency from the latent heat in the surrounding air. It is most efficient when ambient temperature is at 20 degrees Celcius. However when the outside temperature drops and you now want to heat your rooms there is not enough heat in the air for the heat pump. For this reason the heat pump should be increased to at least double the size of what is quoted as the output of the corresponding system rating (Kilowatts). Otherwise you will not have enough power to achieve the desired indoor temperature. This therefore substantially increases the installation and running costs.

The solar energy source is a supplementary and renewal energy source. It can only provide about 30% – 40% of the energy demand, in the event that the sun does not shine. The Primary Energy Source must take over the complete energy demand.