As part of this government funded home energy improvement scheme, they do air tightness tests, before and after.  I think it’s to make sure the extra loft insulation doesn’t suffocate the house.  I did point out that the house is currently a building site, with holes in wall surfaces, daylight visible through gaps around the old windows as we prepare to remove them and insulate the window reveals, and an open chimney flue following removal of the gas fire.  So perhaps the test would not be very informative right now.

But it’s a compulsory part of the scheme, so has to be done.

Air Tightness can be measured by putting a big fan in the door, and inflating the house (or deflating).  You then measure how fast the air leaks out (or in) and can search for leaks:

But this test was was new to me, a simpler way of getting a quick one-off measurement – a Pulse Test.

So those big air cannon blaster things, as they’re almost certainly not called, produce sudden blasts of air.  The equipment then measures how fast the air pressure returns to normal.  Like this:

Video: Pulse Test Air Tightness Test

Our house measured about 4 air changes per hour.

It would be interesting to know how much this improves after completion of the project.  Although I’m not sure I’m interested enough to shell out £150 for another test to find out.