Slough Heat map - more details

The ever-excellent Environment department  at Slough Borough Council have shed some light on their new Heat Map.

It is very similar to the Haringey Heat Loss Map and most of the information on their site applies to the Slough one.

Basically:

• a plane flies overhead about 2 hours after sunset on a cold February/March night. It's done then so it's cold enough for people's heating to be on, but after the effect of the sun heating the roofing surface has faded.
• the measure is of how hot the roof is at that time. It clearly cannot know how hot the house is in the first place, so you can't make any firm assessment of how good the insulation is, just how much heat is being emitted at the time of surveying.

This means that a very poorly insulated house will appear "cold" if the owners are away and the heating off, and a very well insulated house look really "hot" if you're having a massive party and is full of people. Or you're one of the infamous Slough ganja farmers  ...

There's a little bit more to it than that, but that's basically it. It's a very useful guide, but not totally accurate energy survey. But wait, Slough Council have thought of that, and are offering free energy checks for local residents, with subsequent help with insulation, by ringing 0800 043 9569.  It's a relief to know that whilst some of the decisions of the planning committee seem to befar adrift from reality, other departments are getting to grips with the real problems in an effective way ...

Slough Heat-loss map

SBC have published an excellent-looking "Heat Map" of Slough here.


Constructed from thermal imaging photos in March 2008, it claims to show the level of heat loss from all the houses in Slough. Potentially a great tool, but 2 questions come to mind ...

1) just when was the data gathered? To measure how much heat is being lost, the measurement has to be taken at a time when heat is being used within the house.
2) what does the scale 1-7 actually mean? Insulation is measured in "U" units - a measure of the way heat travels through a specific area - http://en.wikipedia.org/wiki/U-value#U-value

The SBC environment team are pretty friendly, and deserve full credit for organising this, so I hope to get some context for the data, pretty though the colours are .... tools like this are going to be increasingly more important as we try to close the energy gap - it's not enough to find new ways of generating energy, we need to reduce the amount we use too.