 This question's from Emma. Is there a delay in when you get hot water if you have a tankless water heater? A lot of people ask me about this. Tankless water heaters heat water in an instant. There is almost no delay and no storage tank is required. When you turn on the hot water faucet, cold water flows through a heat exchanger in the water heater. Then either a natural gas burner or an electric element heats the water, depending on whether you have a gas tankless or an electric tankless water heater. The tankless water heaters that we recommend are from Bosch. Bosch also has a unit with integrated pump to do recirculation. This way you never have to wait for hot water at all.