Let’s get a heat pump into every new home | Brief letters

Environmental nudge | A mad world | The B-word | Abstract artists | Pushing AIRather than wasting time and money on “nudge units” to boost the take-up of heat pumps (Report, 1 January), the government just needs to order housebuilders to install them at the time of construction (ditto solar panels) – gaining cost benefits from economies of scale too. Sadly, MPs don’t seem to have any guts.Norman Miller
Brighton, East Sussex• Re the existential threat of nuclear war (