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# Long description

This is a line chart. It has an x-axis labelled ‘outside air temperature in degrees Celsius’ with a scale running from zero to 20. It has a y-axis with a scale labelled ‘daily space heating energy consumption in kilowatt hours per day’. This has a scale running from zero to 120. At the bottom of the chart is a horizontal line intersecting the y axis at 4 kilowatt hours per day and running right across. This is labelled ‘free heat gains from people’. The area below this is coloured orange. Above this is another horizontal line running right across the chart intersecting the y-axis at 19 kilowatt hours per day. This is labelled ‘normal free heat gains from TV, refrigerator, lights, etcetera’. The area below this is coloured orange. Above this is another line which intersects the y-axis at 26 kilowatt hours per day. This is labelled ‘solar gains to house’. This runs horizontally across the chart from an outside temperature of zero to a temperature of 15 degrees and then curves upwards slightly. The area below this is coloured yellow. A solid line labelled ‘heat loss without insulation’ rises diagonally from the bottom right hand corner of the chart. It has zero space heating demand at a temperature of 20 degrees and rises to 108 kilowatt hours per day at a temperature of zero degrees. It intersects the horizontal solar gains line at just under 15 degrees. This intersection point is labelled ‘balance point temperature without insulation. Another dotted line rises diagonally from the bottom right of the chart. This is labelled ‘heat loss with insulation’. It has zero space heating demand at a temperature of 20 degrees and rises to only 70 kilowatt hours per day at a temperature of zero. It intersects the horizontal solar gains line at a temperature of about 12 degrees. This intersection point is labelled ‘balance point with insulation’.