Tankless water heaters are sized according to how much hot water will be demanded, in gallons per minute, and how hot the temperature needs to be at the point of use. While tankless water heaters are an energy-efficient and convenient alternative to conventional storage water heaters, having them sized properly, or getting the right number of units for your home, is crucial to their good performance.
To determine if one tankless water heater will be enough, list the flow rates of all of your points of use, including the sink, shower, dishwasher and clothes washer. Analyze your usage – does your household use multiple hot water devices at the same time every day? If so, add the flow rates of these devices together to get the maximum flow rate. By installing low-flow fixtures, you can extend the number of points of use that can be run simultaneously. Most households generally run only one or two hot water devices at a time, so carefully analyze your household’s habits before upsizing your tankless water heater. A flow rate of 3 gallons per minute will meet the needs of the average-sized household.
The second component, the temperature, varies from region to region, so it’s best to measure the temperature of your incoming cold water. As a rule, 50 degrees is used as a base-line temperature. Most residential applications will use water up to 120 degrees. The desired output temperature minus the incoming water temperature equals the required temperature rise used in selecting a model.
Once you have determined the flow rate and temperature rise, consider your specific application. Do you want to use a tankless water heater for an entire household, or do you need a single point of use for an isolated location such as a hot tub or a small addition? If you have multiple points of use, are they located in proximity to one another, or further away? Is precise temperature control important? Tankless water heater models range from single points of use, to multiple points of use in close proximity, to entire household capacity, and can regulate temperature with greater precision if required.
To find out the best strategy for sizing a tankless water heater for your needs, consult the experts at Donald P. Dick Air Conditioning, serving the San Joaquin Valley since 1970.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about tankless water heaters and other HVAC topics, download our free Home Comfort Resource guide.
Donald P Dick Air Conditioning services the greater Fresno area in California. Visit our website to see our special offers and get started today!