If the original poster wanted a better supply of hot water rather than
saving energy.

you can but a regular hot water tank with larger capoacity like 75
gallons and a bigger BTU burner. regular burners are around 40,000 BTU,
high recovery like 75,000 BTU. these tanks while costing more are still
less than a tankless, while supplying a much better supply f nice hot
water.

thats what I did, in 2000, it cost a 200 more than a regular tank but
we have been very happy wih it.