Startup Idea : Hot Room Temperatures required in winters

We use Split ACs in bedrooms or offices, for summers & other hot days; But what about the winter or cold days. The same unit can be converted into Hot Air Blower. The same distribution system for cold air can be utilized for hot air also. The new system can be made run on solar energy which makes hot air ( & also can make hot water if required ) The same should be attached to the mother unit of the present system & so in one system itself u can get both the benefits; which is till date not operative anywhere, as per my knowledge but can actually make a revolution around the world. All the present installations can be also be updated; as it is an addon facility.