So let’s look at options available for space and water heating in the home:

Solar collectors:

These are mainly installed to provide free, clean heat for domestic water. Solar energy varies considerably seasonally. It provides about ten times more energy in the long mid-summer days compared to mid-winter with much less solar intensity and short daylight hours. Most solar systems can more than satisfy their Summer use but need to be supplemented by another energy source in Winter. As domestic hot water is needed all year round, it is the obvious first choice for solar. Whereas, space heating is badly needed in the cold mid-winter, when solar is at its minimum. To maximise solar for hot water use all year round, the collectors can be pitched at angles from 25% to 60%, and oriented from South East through South to South West. For hot water use, the size needed for collector area, depends on the number of occupants in the house, using showers, etc, how close the panels are oriented to due South and the type and efficiency of collectors. Typically collector areas of about 1.5 sq. metres is required per person for domestic hot water. The collector types can vary from evacuated tube, reflector, flat-plate, warm-air panels or even slate/roof tile, cladding types. These systems can typically deliver about 60% of the total domestic hot water needs of an average family and preheating the cold supply water to the cylinder in the Winter. Solar collectors need to be backed up with a large, vertical pre-insulated ‘buffer- tank’ to store solar heat. The volume of the buffer-tank is critical to match the solar energy being supplied and the demand required for hot water use. The capacity may vary from between 200 and 500litres for hot-water storage. The heat exchange coil should be fitted at a low level in the vertical vessel, where lower-temperature solar heated water can preheat the colder water at the bottom and the cold supply water entering the tank.