Water temperature for watering orchids

[amstutz1]

I am replacing my greenhouse with a larger one. I have used a five gallon hot water tank for the past ten years but usually run out of warm water about half way thru watering the plants. Our water temperature from our well is about 52 degrees F. I am debating whether to eliminate the hot water heater or replace it with a larger one. I would appreciate others opinions.
Mike