Solar off grid?

I have been toying with the idea of getting a small solar off grid setup for the office.

If I intend to only be in there 4 hours a day, in 2x2hour blocks, I figure I can’t use THAT much electricity. Can I?

I’ll have my laptop, a screen, some lights and a few peripherals like a printer. By far the largest consumer of power would be heating, but if the room is super insulated and I’m not in there all day, am I really like likely to use that much.

I really need to do some maths on this one - it’s looking like it could be a load of money for something large enough. All because I can’t be assed to get someone in to wire the place into the mains.