Need to choose water heaters for a hotel renovation. 2 buildings, both had 100gal 200k btu natural water heaters previously, reviews mention running out of hot water.

Building 1 - 20 rooms, all small, 1 bed, hot water plumbing fixtures 20 showers, 20 vanity sinks.

Building 2- 7 rooms (2 large suites with 2 beds, 5 smaller 2 bed), 2 commercial laundry machines for hotel linens, small lounge kitchen with commercial sink and small under counter commercial dish washer, 1 lobby unisex bath with vanity sink.

Assume both buildings need hot water loops so hot water is readily quickly available to each fixture, long waits will be a big issue, as would running out of hot water. With that said, project is over budget so don’t want to over spend if no tangible benefit to the hotel patrons, life expectancy of appliance or gas bill.

On demand type systems seems appealing, I’m not sure mechanics of plumbing a hot water loop with on demands and not have the heaters running full time, I have done them on tank units very simple.

Not against tank units also if makes sense. Please advise.

Thanks!