I would pass due to the time constraints. That sounds absolutely horrible. Do you need this account to keep your business alive? Are you struggling to find residential work?
But, also, will you have to move that stuff? Do you need to wait for someone to move that heavy stuff with a forklift? What about moving stuff and removing posters inside? Will you have to wait for someone to turn up to unlock for you, causing a disruption to your work flow? Are they expecting you to clean behind those window signs? Is there enough room inside to work comfortably and safely with an extension pole? Did they have a window cleaner before? What happened to them (Its a red flag if they were actually happy with them, but now can’t get in contact)? If they didn’t have a window cleaner, why? When was the last time they were professionally (or otherwise) cleaned? Did they just get the cleaners to do them? Are the auto doors easy to operate, so you can clean them without setting them off? Will you need to get someone to operate the doors for you while you clean? Will there be customers coming and going that will interrupt your flow? Will left over water be walked in by customers? Do the frames catch and hold water, causing nasty drips? Do they have any issues with water leaking in? Is it on a main road? Whats the lighting situation if you’re in the dark?
These are all questions you need answers to before quoting. If you do really want a figure, and without knowing specifics, I’d quote AUD$350-$450, absolute max would be 3 hours, and that’s if I had to move stuff (excluding the forklift bit at the front).
For me, this would take me away from my high paying resi customers and mess up my daily routine. I feel as though it would be a massive drag every time this account rolled around and I had to work within a small window either side of the day.