On Sunday, 26 November 2017 22:01:04 UTC, David WE Roberts (Google) wrote:
This makes using a wood burner in the shed a pure vanity project.
So on pure cost effectiveness on fuel use the air source heat pump seems
to win hands down.
It does make the installation of air conditioning in the house look quite
attractive, though. Purely for cooling in the summer, though,

If the house and shed are close enough together could you use one outside unit and two inside units, one in the shed for winter warmth and the other in the house for summer cooling?

Or one of the type that works with an inside unit and 2 four-inch vents through the wall, and move it from house to shed in autumn and spring?

Also if you can run your aircon off solar electricity that may change the economics.

Owain