We are currently building a home office/hangout room/gym in our garden and looking at options for heating it. The building will be done in ICF as the site is sloping and will need retaining walls anyway, so it will be well insulated and air tight. It will be split into two rooms (at two levels). I would like to take advantage of high insulation and keep it as energy efficient as possible. Nevertheless it will still need some heating. The options that I have come up with so far are:
Any advise or thoughts greatly appreciated. Probably not relevant to the question, but I am also considering adding solar PV to the roof. The roof is east-west facing which is probably not ideal, but have solar thermal on roof of house so no room there for pv panels.
Re Heating, have you researched far infra red, not for me but could be for you. They heat you, not empty air space
Regarding connecting to the house heating system, ok if it is gas or oil but if there is a heat pump supplying the house it would have been sized and commissioned for the heated volume and therefore may not be adequate for the extra volume of the office. An air to air heat pump would do the job especially if you have alot of glazing as these ICF builds are prone to overheating and the unit can cool the air as well, however it is not a ventilation system. As you say, the single room HRV's are probably the way to go.