How much time does it take? In the US almost all shower-heads and faucets will only use a maximum of 2.5 gallons per minute. For me the water will get hot in ab

How much time does it take? In the US almost all shower-heads and faucets will only use a maximum of 2.5 gallons per minute. For me the water will get hot in about 30 seconds. So I am using approximately 1.25 gallons of water. For me that is acceptable.