When it comes to the tankless waterheater gas is perhaps the top option. It is not, of course, the only option, but it is consistently one of the best value and most impressive performance fuels.
Other tankless waterheater are available - powered by oil or electricity - but the gas is closer to instant than oil and generally offers much larger capacities than electrical.
Of course the electric tankless hot water heater is ideal for many situations, but there are not many models that claim to match gas for whole house coverage.
The things to look out for with gas on demand hot water heaters are efficiency and capacity.
For a gas tankless hot water heater an impressive efficiency rating is in the mid eighty percent upwards. This is achieved by clever use of spare heat in what is called a condenser unit.
Gas on demand water heaters also provide a steady flow of hot water at a given number of gallons per minute. This is given by the manufacturers, and is naturally dependent on how cold the incoming water is.
So when it comes time to compare tankless water heater and find the right model for you, always choose a high efficiency unit that can churn out the right amount of hot water you need.