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How To Size Tankless Hot Water Heater

How do I know what size tankless water heater I need?

How to Select the Right Size Tankless Water Heater Determine the maximum number of devices you want to run and their total flow rate. Then, add up their flow rates (gallons per minute). Determine required temperature rise. Sizing Example: An average shower will be between 104–106° and uses 2.6 gallons of water.

What size tankless water heater do I need for a family of 4?

What Size Tankless Water Heater Do I Need For A Family Of 2, 3, 4, 5, Or 6? Number Of Family Members: Gas Tankless Heater Size (GPM) Electric Tankless Heater Size (kW) What size tankless water heater do I need for a family of 3? 7-9 GPM 15-23 kW What size tankless water heater do I need for a family of 4? 8-10 GPM 20-28 kW.

Can you have too big of a tankless water heater?

Tankless water heaters provide endless hot water on demand. Choose too small of a system and it won’t have the capacity to provide enough hot water to meet your household needs. Go too big and you will overpay. This is why proper sizing is key – before making a purchase.

How many gpm should a tankless water heater?

SELECTING A TANKLESS WATER HEATER Consider how many of these needs you may have simultaneously to determine the maximum flow rate you require. For a home with 1 bathroom, we recommend 6-7 GPM; 2 bathrooms, 8 – 9 GPM; and 3+ bathrooms, 9-11 GPM.

Is it worth switching to a tankless water heater?

The big advantage of tankless water heaters is that they use less energy since they only heat up water when you need it. You can save hundreds on your energy bill each year. Because they don’t waste power, you can also enjoy the fact that your home will be more sustainable and eco-friendly.

How do you size a Rinnai tankless water heater?

To find the ideal tankless water heater size for your home, you will need an idea of how many gallons per minute (GPM) you will need. Here are some examples of items used in the home and how many GPMs are used.

Why is tankless water heater installation so expensive?

Installation is expensive because the unit needs a bigger gas supply than a conventional water heater does, and it needs to run its own exhaust flue to the exterior. Installation costs can vary widely, depending on the location of the flue and the gas supply. The unit itself costs between $800 and $1,000.

Does a tankless water heater save money?

According to Energy.gov, “For homes that use 41 gallons or less of hot water daily, demand (or tankless) water heaters can be 24% to 34% more energy efficient than conventional storage tank water heaters.” Tankless water heaters (if gas-fired) will save homeowners over $100 annually the longer they remain in service.

How many tankless hot water heaters do I need?

For larger households that typically use more than 85 gallons per day, two tankless systems, or the largest available model, are likely needed. For smaller households that use under 40 gallons per day, one unit should suffice.

What size hot water heater do I need for a family of 2?

In general, a 40- to 50-gallon tank is sufficient for an average household of 2 to 3 people, increasing by 10 gallons per additional person in the home. In a tankless water heater, the capacity is measured by flow rate, calculated in gallons per minute.

What size water heater do I need for a family of 5?

If your family size is 5 or more, you’ll need an 80-gallon tank (electric) or a 50-gallon tank (natural gas or liquid propane).

How many gallons does a tankless water heater hold?

In general, gas tankless water heaters can heat up to 5 gallons of water up to 70 degrees Fahrenheit in one minute while electric tankless water heaters can heat only 2 gallons of water to 70 degrees Fahrenheit within the same time.

Is 1.75 gpm enough for a shower?

Since 1992, a maximum of 2.5 GPM is the federally mandated flow rate for new shower heads. This means no more than 2.5 gallons of water should flow out each minute. If your current shower head was made in the 1980’s or 1990’s, its flow rate could be 3.5 GPM or more!.

What is the downside of an electric tankless water heater?

The main disadvantage of tankless water heaters is their upfront cost (unit and installation) is significantly higher than tank-style heaters. they take longer to deliver hot water. the water temperature is inconsistent when multiple outlets are on simultaneously. they cannot provide hot water during a power outage.

How much does it cost to convert to a tankless hot water heater?

An electric tankless unit will cost about $500 to $700, roughly the same as a traditional tank model, while the cost of a gas tankless heater runs about $1,000 to $1,200. Beyond the initial cost, the national average for the installation of a tankless unit is slightly over $1,700.

How many years does a tankless water heater last?

How Long Do Tankless Water Heaters Last? Gas-burning tankless water heaters should operate for 20 years or more, two or three times longer than tank-type heaters. Tankless electric units have shorter life spans, on the order of 7 to 10 years.