I agree that with some modifications it could work for renters too, perhaps by simply offering things a la carte.
That being said, did you consider Task Rabbit? It seems like they might have been able to help you with your air conditioner install. Or perhaps not if it required a more skilled professional.
Don't forget that at a certain point of client & services, the company will need to be getting bonded contractors.
That said, whatever site mediates this, would potentially need to have 24x7 customer service, a billing platform (with payouts), and potentially some decent liability insurance.