Which heating system (with hot water) would make sense in a tiny house?

Hello everyone. I am planning to build a tiny house with about 20 sqm of living space in my garden (2500sqm2) as a backup for adult children and other visitors since we ourselves live in a small bungalow. It will be almost fully equipped. All connections are available. The walls, floor slab, and roof structure have a U-value of 0.18 W/(sqm2K), resulting in a heating load of 1.4 kW.

Instant water heaters and for heating fan heaters or as a luxury option IR panels. If continuous or frequent heating is needed, maybe consider split air conditioning.

Fan heater or an air conditioning unit.

Split air conditioning or the US quick and dirty variant in the window (window air conditioner)

alternative a small wood stove or makeshift a gas heater from a caravan.

In principle, an oven would also work. Something electric is practical, however, to keep the place automatically frost-free.

I tend to favor tankless water heaters and infrared panels with simple plug-in thermostats like . Maintenance-free and inexpensive to purchase and for occasional use.