Hands up those who have worked on or built an eco-house/low energy dwelling recently. Now tell me this – where did you put your cold water pipes? This may seem an odd detail to ask, especially as it’s usually the hot pipes that us heating engineers are interested in. But what is so often forgotten is that every time we rinse our clothes or flush the loo, then we bring in quite a lot of liquid that is on average ten degrees cooler than we normally maintain our rooms at. If this lingers within the heated ‘envelope’ of the house, it then rises to the same inside air temperature to be then flushed away, this needlessly adds to the heating load of the house.
I’ll agree it’s a small amount (perhaps 200 kWh loss per annum per household) but why don’t we simply avoid the loss during construction and put the cold feed and cistern storage away from heated areas. In well-insulated homes, this would be sensibly somewhere part-insulated for frost protection but outside the greater thickness of insulant. The use of high-level or concealed WC cisterns rather than close-coupled ones makes this task easier. In all cases, hot and cold domestic pipes should be generously separated and I suggest insulated from each other ...
