@Edent @paul When our combi boiler died recently, I also looked in all ASHP and replumbing to use Octopus Go as an iBoost type solution. No tank and the all the associated disruption you detail made it just not worth the cost. I'm taking solace in a much more efficient combi boiler. Aside: two difference plumbers dismissed ASHP and solar + immersion and said hydrogen was the future. I didn't get into that argument.