Tankless water heaters are becoming an increasingly popular choice for Canadian homeowners looking for a more energy-efficient and space-saving option. Unlike traditional tank-style water heaters that store and constantly heat a large volume of water, tankless heaters heat water on-demand, providing a continuous supply of hot water while consuming less energy. If you’re considering buying a tankless water heater, sizing is one of the most important factors to consider. In this blog, we’ll discuss how to size a tankless water heater and what size tankless water heater you need for your Canadian home.
Step 1: Determine your peak hot water demand
Determining your peak hot water demand is the first step in sizing a tankless water heater. This is the maximum amount of hot water you’ll need at any given time, which is typically during the morning or evening when everyone in the household is using hot water simultaneously. To calculate your peak hot water demand, add up the flow rates of all the fixtures and appliances that will use hot water simultaneously. Here’s a list of common flow rates per fixture:
- Showerheads: Most showerheads have a flow rate between 1.5 and 2.5 gallons per minute (GPM). Low-flow showerheads can have a flow rate as low as 1 GPM.
- Faucets: Kitchen and bathroom faucets typically have a flow rate between 1.5 and 2.2 GPM. However, low-flow faucets can have a flow rate as low as 0.5 GPM.
- Washing machines: Top-loading washing machines have a flow rate between 2 and 3 GPM, while front-loading washing machines have a flow rate between 1.5 and 2 GPM.
- Dishwashers: Most dishwashers have a flow rate between 1.5 and 3 GPM.
- Bathtubs: A typical bathtub can have a flow rate between 4 and 6 GPM, depending on the size and type of bathtub.
For example, if you have a showerhead with a flow rate of 2.5 gallons per minute (GPM) and a washing machine with a flow rate of 3 GPM, your peak hot water demand would be 5.5 GPM.
Step 2: Determine your desired temperature rise
The next step is to determine your desired temperature rise, which is the difference between the temperature of the incoming water and the desired temperature of the hot water. In Canada, the incoming water temperature varies by region and season, but it’s typically between 4 and 15 degrees Celsius. The desired hot water temperature is usually between 38 and 49 degrees Celsius. To calculate your desired temperature rise, subtract the incoming water temperature from the desired hot water temperature. For example, if your incoming water temperature is 10 degrees Celsius and your desired hot water temperature is 49 degrees Celsius, your desired temperature rise would be 39 degrees Celsius.
Step 3: Calculate the required flow rate
Once you know your peak hot water demand and your desired temperature rise, you can calculate the required flow rate of your tankless water heater. This is the minimum flow rate the tankless water heater must be able to handle to provide hot water at the desired temperature. To calculate the required flow rate, multiply your peak hot water demand by your desired temperature rise. For example, if your peak hot water demand is 5.5 GPM and your desired temperature rise is 39 degrees Celsius, your required flow rate would be 385 GPH (gallons per hour).
Step 4: Choose the right size tankless water heater
Finally, it’s time to choose the right size tankless water heater for your Canadian home. Tankless water heaters are typically sized based on their maximum flow rate and their ability to maintain a certain temperature rise. You’ll want to choose a tankless water heater that can handle your required flow rate at your desired temperature rise. It’s important to note that tankless water heaters are often rated for different temperature rises, so make sure you’re comparing apples to apples when choosing a unit. Additionally, you’ll want to consider other factors like the size of your home, the number of bathrooms and fixtures, and the number of people in your household.
While calculating the required flow rate for your tankless water heater can be time-consuming, you can simplify the process using our free tankless water heater sizing tool. However, it’s important to note that choosing the right size tankless water heater involves several factors and can still be complex. Therefore, we highly recommend that you seek the advice of a professional, such as the experienced team at Affordable Comfort Heating and Cooling. With our help, you can ensure that your tankless water heater is sized correctly and that your family can enjoy endless hot water for years to come. Our experts can guide you through the selection process, provide expert installation services, and answer any questions you may have. Enjoy the many benefits of a tankless water heater without worrying about the sizing or installation process by partnering with Affordable Comfort Heating and Cooling.
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