Does it work?
Here is a graph showing how the insulation reduced the gas consumption for a large semi detached house in the South of England. It shows gas consumption versus temperature both before the insulation (magenta with orange trend line) and after (blue with green trend line). AS you can see the gas consumption dropped by about 40%
The insulation paid for itself in one year.
How was it measured?
This uses DrDaq, a small low cost data acquisition system from Picosoft
The temperature monitoring runs continuously saving data to a .plw file. Meter readings are done periodically and the readings stored in a database. The diagram below shows how it works.
The chart above was generated from the database. Note - readings for very low temperatures have been excluded because the gas boiler has limits on how much gas it can so at low temperature the gas consumption tends to be the same - but the house is warmer.