When it comes to powering a tankless water heater, the size of the propane tank is a crucial consideration. The right tank size can ensure efficient and reliable hot water supply, while an undersized or oversized tank can lead to various issues. In this comprehensive guide, we’ll delve into the factors that determine the appropriate propane tank size for your tankless water heater, providing you with the knowledge to make an informed decision.
Factors to Consider
The size of the propane tank needed for a tankless water heater depends on several key factors:
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Climate and Groundwater Temperature: The climate and groundwater temperature in your region play a significant role in determining the required tank size. Colder climates and lower groundwater temperatures will necessitate a larger tank to accommodate the higher heating demand.
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Flow Rate: The flow rate of your tankless water heater, measured in gallons per minute (GPM), is a crucial factor. The higher the flow rate, the larger the propane tank needed to meet the demand.
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Temperature Rise: The temperature rise, or the difference between the incoming water temperature and the desired output temperature, also affects the tank size. A higher temperature rise will require a larger tank.
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Household Size and Simultaneous Usage: The number of people in your household and the number of appliances that may be used simultaneously can impact the required tank size. Larger households with higher simultaneous usage will need a larger propane tank.
Calculating the Propane Tank Size
To determine the appropriate propane tank size for your tankless water heater, follow these steps:
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Determine the Flow Rate: Start by calculating the maximum flow rate required for your household. This involves adding up the flow rates of all the major appliances that may be used simultaneously, such as showers, sinks, dishwashers, and washing machines. A typical flow rate for a family of five in a northern state is around 10 GPM, while a household in a southern state may require a flow rate of 7 GPM.
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Calculate the Temperature Rise: Next, determine the temperature rise required for your home. This is the difference between the incoming water temperature and the desired output temperature. You can reference a map of average groundwater temperatures to estimate the incoming water temperature for your location.
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Choose the Appropriate Tankless Water Heater: Based on the calculated flow rate and temperature rise, select a tankless water heater that can handle these requirements. Manufacturers will provide the maximum GPM flow rate at different temperature rises for their models.
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Determine the Propane Tank Size: The size of the propane tank needed will depend on the tankless water heater’s specifications and the calculated flow rate and temperature rise. As a general guideline, a family of five in a northern state with a 10 GPM tankless water heater and a 70°F temperature rise may require a 100-gallon propane tank. However, it’s essential to consult with a professional or the tankless water heater manufacturer to ensure the appropriate tank size for your specific needs.
Considerations for Propane Tank Placement
In addition to the tank size, the placement of the propane tank is also an important factor to consider. The tank should be located in a well-ventilated area, away from any potential ignition sources, and in compliance with local building codes and regulations. It’s recommended to consult with a licensed propane technician or your local authorities to ensure proper and safe installation.
Conclusion
Determining the appropriate propane tank size for a tankless water heater requires careful consideration of various factors, including climate, groundwater temperature, flow rate, and household usage. By following the steps outlined in this guide, you can ensure that your tankless water heater is paired with the right-sized propane tank, providing your home with reliable and efficient hot water supply.