Graphic Design

I'm in the business of smart home and building control systems that includes condition monitoring. I want to display controls for heating, lights etc on a floor plan and information about the heating, solar and hot water system on diagrams, this might include temperature measurements as per my basic example. I just require the background image, possible with some overlays showing lights on/off etc. (but keep it simple at first). I'm no artist, so what I'm looking for is someone who can produce something very pleasing to the eye, perhaps a "sketched" look, but I'm very open minded. Darker colours tend work best as there will be the text overlays as part of the control of each element. This is a start-up venture so budget is very limited, would suit a freelance person looking for a potential new market. Obviously I'll pay for the initial work (which will be used in my home for the demonstration to potential clients) I'll use my home as examples and videos on my web site to sell the system to prospects. The graphics package would customised to each customer will be forwarded on to you as opportunities develop, so I am looking for an ongoing relationship as each project is unique. The images below are actual construction drawings and a typical heating system diagram. I imagine each room as a sketch to give a modern and retro high-tech look, but I'll take the advice from an expert!