I am looking for a gas hot water heater I can instal in a crawl space. I have 3-4 feet of headroom. It needs to be big enough to supply all the hot water for a 4 bedroom house. However the water system does not supply enough water for 2 showers at once. Bosh makes a tankless heater that would fit, but I am not going to spend the $1000 for it. I plan to instal it myself.

I presently have a 40 gallon tank in the garage with about 30 feet of pipe to the most used lavatory. It is over 20 years old, and likely will need replaced soon. When I replace it, I am mostly interested in installing the new one closer to where the hot water is used the most often to avoid the long waits for hot water. The gas meter is close to where I want the heater, and has 1 inch pipe.

I don't think my electrical system has the capacity to switch to electric.