Griffin takes a room at the inn in Iping, a Sussex village, swaddled in bandages and blue goggles, works behind drawn blinds, and turns violent when the village will not leave him alone. He is a poor demonstrator at a provincial college who dropped medicine for optics, robbed his father to pay for the work, and matched his own body to the refractive index of air. Wells is best on the nuisances of it: you go about naked and freezing, snow settles on you, mud takes your footprints, dogs still smell you, and your dinner shows until it digests. Fair warning that the opening third is broad village comedy, landlady and vicar and all, before it hardens into a manhunt.
The Invisible Man is 48,641 words. At an average adult reading pace of 300 words a minute that is about 2 hr 42 min, or roughly 2 hr 2 min if you read quickly and 4 hr 3 min at a more deliberate 200 words a minute.
That count is measured from the complete public-domain text rather than estimated from a page count, so you can compare all the books side by side.