Underfloor heating at 200w/m2 is from our Conservatory range, but good to also use in Kitchens as you will lose some floor space to the Kitchen units.
Will be full heating (primary heat), depending upon the heating coverage of the total gross area, how well the dwelling is insulated and the heat loss figure for your gross area.
As over, 10mm insulation in the floor also.
The Heat loss figure for your area is about how each surface loses the heat: Floor surface, internal walls, external walls, doors and ceiling.
Very long winded calculation, but in general 200w/m2 is good for any Conservatory, so will be good for a Kitchen.
Warm regards, Keith.
