The right heating depends on the envelope you have already specified. Decide the two together, and decide both before production.
A small heat pump suits a good envelope
In a well-insulated, airtight compact house the heat demand is low enough that the smallest air-to-air units are oversized rather than marginal. That is a good position to be in: the unit modulates down and runs quietly instead of cycling.
It also gives cooling in summer, which in a house with a large glazed elevation is not a luxury. The cost is an outdoor unit that has to be sited where its noise does not fall on the terrace or the neighbour.
A wood stove is independence with obligations
A stove works when nothing else does, and in a small volume a 4 kW unit is usually the smallest available and still too big. It needs a compliant flue, a hearth, a dedicated combustion air supply and somewhere dry to keep a season's wood.
It also needs a person. As a sole heat source for a rental unit it is a liability; as a supplement for an owner who enjoys it, it is the best thing in the house on a February evening.
Electric panels are simple and expensive to run
Direct electric heating has no outdoor unit, no flue, no service interval and the highest running cost per kilowatt-hour delivered. In a house that is occupied three weekends a month, that arithmetic can still come out ahead of a heat pump.
Infrared panels heat surfaces rather than air, which suits intermittent use — the room feels warm faster. For continuous occupation the standing cost dominates and a heat pump wins clearly.
Underfloor or radiators or air
Water-based underfloor in a compact floor cassette adds build-up height and thermal mass that a lightweight building responds to slowly. Air distribution is faster and matches how a small, well-sealed house actually behaves.
If you want the comfort of a warm floor, a small electric mat in the bathroom gives most of the perceived benefit for a fraction of the complication.
Size it on the coldest week, not the average
Heating capacity is chosen against the design outdoor temperature for the site, which differs sharply across the five markets. A unit sized on a Dutch winter is short in a Swiss valley and oversized on a Mediterranean coast.
Give the supplier the destination before the specification is fixed. The insulation, the glazing and the heat source are one decision made three times.