Should My On-Demand Water Heater Take This Long To Heat Water?

An on-demand water heater does away with one of the biggest drawbacks of conventional storage tank water heaters – the tank. Heat loss from the storage tank often wastes energy because water must be repeatedly reheated throughout the course of the day so it will be ready whenever there’s a demand. Also known as tankless water heaters, on-demand models heat water as it’s needed and store no reserves. As soon as a hot water tap is open, the tankless model senses flow and flash-heats water with electric coils or a gas burner. As long as the amount of hot water demand is within the rated capacity of the model, a tankless water heater should theoretically never run out of hot water.

Because no water is stored in a tankless model, there will always be a short delay – known as “lag time” – as the system flash-heats cold water flow to the correct temperature. Ideally, this should be no more than a few seconds. Extended lShould My On-Demand Water Heater Take This Long To Heat Water?ag times can result from two factors:

Maintenance issues. An on-demand water heater requires annual de-scaling to remove mineral deposits that naturally form on the heat exchanger inside the heater.  Deposits may diminish heater performance and result in a longer lag time before cold water reaches desired temperature.

Location issues. The farther the water heater is located from the point of demand, the greater the volume of cold water that has to be pushed through the pipe before hot water arrives at the tap. A smaller, dedicated on-demand water heater can be located at or close to a high demand point to cut lag time. Another option is a hot water circulation pump. At preset intervals, the pump automatically circulates hot water through the plumbing to replace water that has cooled, which is re-circulated back to the water heater for reheating. This ensures that water waiting in the pipes is always hot when you need it.

For more information on getting maximum performance and efficiency from an on-demand water heater in the Cleveland area, please contact us at Geisel Heating, Air Conditioning & Plumbing.

Our goal is to help educate our customers in Cleveland, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about water heaters and other HVAC topics, download our free Home Comfort Resource guide.

For those Do it Yourselfers who would rather take control of your own indoor comfort, you can shop our online store for replacement parts, products and accessories!  

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