Isn a high efficiency warm air furnace or boiler nearly as cost effective as Infra-red heating?
No. Fuel economy is accomplished through methods far beyond just combustion efficiency. Even a furnace or boiler with 90% + AFUE often is no challenge to a properly designed Infra-red heating system. The simple fact still remains that regardless of the heating appliance combustion rating – warm air is still the means of distribution. And this warm air, even if produced more efficiently, still convects upwards & away from the primary heat zone. Cold floors still remain, & the heat has not been stored in thermal masses as with Infra-red heating. Infra-red heats objects, thus re-radiating & heating the building from the floor level up.