Our customer owns a terraced town house in London SE19.

It was late when we finished
He had considered a solar hot water system in the loft, as he wanted to minimise his family impact on the environment; with solar hot water it is important to maximise the hot water storage, or you quickly run out of solar heated water and have to use the boiler.
Unfortunately, the design of these properties leaves a low headroom in the loft, restricting the size of cylinder, and there is limited weight capacity for large volumes of water.
So, instead, he decided to fit the Vaillant ecoTEC+ 937 hybrid combination boiler. The wall hung unit comprises an 837 combi with a set of hot water storage tanks built in a pod at the back. This makes the boiler quite large and heavy (getting on for the size of a washing machine), but it delivers a superb performance of 20 litres per min for the first 200 litres of drawoff.
We fitted the new boiler on the brick gable wall and used a vertical flue system. Five new radiators were also supplied and fitted, and we were fortunate to be able to use some existing ductwork from a warm air installation to hide most of the pipework.

New Vaillant 937 in the loft
The Vaillant 937 is a good alternative to an unvented cylinder and boiler in a medium sized house, because it takes up relatively little space. Other similar solutions offered by Hot Water & Central Heating include the Worcester Highflow CDi range.