By the power of Logs!

The owners of the Touchwood built Porters house (on the gallery page) have been keeping a record of how many logs they use to provide all the heating and hot water requirements for their home, please see the graph below:

the graph, which runs from summer 2014 to summer 2015, shows the solar panels provide all hot water during the summer periods, and some contribution during autumn / spring.  On cold winter days a 4 hour burn provides all hot water and heating for a 24hr period. In total they lit the fire 89 times during the graphed period, using 33 barrows of wood. This shows the point of building the passivhaus way - so little heat is needed that it can be delivered via a small log boiler, and Porters is a large house (290m2).

The small log stove with back boiler is an attractive centre piece for the lounge which since they source their own logs, provides free thermal energy. Logs boilers have other advantages too - they are near to carbon neutral - the carbon released when burnt was absorbed by the tree when growing, so no net change in atmospheric CO2 levels (bar that emitted during log processing). Also if you buy logs, you are supporting your local log processing / woodland management industries - surely better than paying for oil to be extracted from the ground to support the fossil fuel industry? One day it might even revive our ancient coppice woodland which when managed provides a superb habitat for insects and wild life.