Agreed but the UK (assuming you are UK based) made such a hash of forced air the first time around that it's unlikely to ever see much uptake. You can do elect

Agreed but the UK (assuming you are UK based) made such a hash of forced air the first time around that it's unlikely to ever see much uptake. You can do electric underfloor upstairs but water is a no go upstairs unless you are concreting. The best balance is water based underfloor downstairs, underfloor electric in upstairs bathrooms + a heated towel rail (water or electric) and then water filled radiators upstairs that either run off a traditional boiler or an air source heat pump. You could use a ground source heat pump but, depending on how far north one is this can land up freezing the ground and creating a kind of localised permafrost unless you run the system backward in the summer. You could also use solr thermal if happy with balck panels on the roof.