Payback reported for those heat pumps, at most

2 years2024-26sourcedmedium confidence

The farm, as reported. 'Less than two years': an upper bound, not a measurement.

The Guardian (from Canary Media), 'It bloody works': why the world's oldest cheddar-maker uses a 'milk-source' heat pump, 17 September 2026'the payback on its heat pumps is less than two years'