As cats cost about £120pa to ‘run’ this equates to a total running cost of £2,160.00 pa.
This cost can be compared to £167.00 for gas or £327.00 for Electric, though the installation cost is of course less for cats.
The calculations have used an average heat load. In reality the heat load will vary considerably through the year. You will need considerably more cats in colder weather and less during mild weather.
In hot weather you can of course let the cats out for a run about, but this represents a significant waste of resources if you continue to feed them!
As cats cannot be used for cooling, you would also have to introduce an alternative cooling system such as lizards or other cold blooded animals.**
In summary then,
cats are expensive…