"June Hughes" wrote
| >... June insists that we only have ventilation through the
| > cat flap.
| What is your heating run on? You should have a ventilator in the
| wall. (Or something equivalent). The cat-flap is not good enough.
| This is not a joke, or a cheeky comment, Dave.

Almost all British boilers are room-sealed, and take in air for combusion
and expel the by-products of combustion through a balanced flue to the
outside.

More stringent energy efficiency requirements mean that it is now difficult,
and will soon be almost impossible, to fit an open flued gas boiler in a new
installation.

Owain