It takes power to heat water. This is a basic fact of science. However, the water that goes into your houses' boiler is particularly cold, having arrived fresh from the main water supply. Therefore it takes needless extra energy to heat it up.
The alternative is to make our own hot (or at least warm) water and so save energy.
As a DIY project it is perfectly possible to heat your water by by an average
20% in cold northern lattitudes without paying for power. This saving is not
only beneficial to the environment but saves yuo a lot of money. As the cost
of fuel is set to double within five years, setting up a system now could
be a real investment and could increase the value of your home.
There are a number of different approaches to heating water. This article will focus on just three:
There are two ways of extracting heat from thre ground. The first is to drill a deep borehole to a depth of between 15 to 100 metres (in general the deeper the better) and a sealed pipe loop is inserted down the hole.
A small pump circulates water and refridgerant in the pipe bringing water warmed by the ambient temperature of the ground to the surface. This warmth can then be given up to a hot water tank.
A cheaper to install although less effective method is to bury the sealed pipe just a metre or two below the surface. This requires a large garden but is certainly cheaper to set up.
Each square foot of sunlight can generate up to 100 watts, or 300 BTU of heat on a bright sunny day. Even on a cloudy overcast day about of quarter of that is still being produced. With this in mind it makes sense to investigate direct solar heating.
Popular in hot climates, a series of black pipes laid on a roof absorb heat diretly from the sun and a small pump pushed water around the system. The most basic of these setups are known as Flat Plate Collectors. More advanced systems (better suited to colder climates set the water pipes within mirrored parabolic half pipes to increase heat generation.
The same principle as the two systems above, but the heat is generated through the microbial activity of a large garen compost heap. This technique is known as thermophilic compost heating or bacteria fueled heating.
In all three cases, carbon savings can be made by ensuring the electricity used to power the small pump comes from a renewable energy source such as photovoltaic cells.