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How To Size A Tankless Water Heater

If you are in the market for a new water heater, you may want to consider tankless hot water heaters. This style of hot water heater can offer you several different benefits. You will also need to know how to size a tankless water heater.

What Is A Tankless Hot Water Heater?

A tankless hot water heater is a water heater that does not have a tank like traditional water heaters. When you turn your faucet on, cold water is immediately converted into hot water. You will have lower utility bills because there is no need to heat the water constantly like traditional water heaters. Tankless water heaters are also space-saving, taking up a lot less room than traditional heaters.

Sizing Your Water Heater

You will need to figure out the proper water heater size. If you get the wrong size, it may not be able to heat the water in your home well. This is especially true if you are trying to use multiple bathrooms or appliances at the same time.

You can figure out How To Size A Tankless Water Heater by doing the following steps:

Step 1:

Sit down and determine how many devices you will want to have hot water, and then determine their flow rate. The flow rate is the gallons per minute that you will need in water flow.

If you want to run your shower and faucet at the same time, you will need to determine their flow rate. A hot water faucet should have a flow rate of around 0.75 gallons a minute. The shower head will have a flow rate of 2.6 gallons. Your hot water heater should be able to provide at least 3.26 gallons of hot water a minute. If you want to get your flow rates lower, you can always install a low flow water faucet and shower head.

Step 2:

You will want to determine the temperature rise you will need for your devices. You will need to subtract the incoming water temperature from the output temperature. You will want to always assume that the incoming water temperature is 50°F if you do not know your water temperature for sure. This will help to ensure that you do not undersize your tankless hot water heater.

It is important to know that your incoming water temperature will be higher if you live in a warmer area. You will want to use 105 degrees to 115 degrees. If this is the case, you will need to make sure the tankless water heater can provide a temperature rise of 55 degrees.

Sizing Example

When you use a shower, it will use 2.6 gallons of water per minute, and you will need a shower temperature of 104 to 106 degrees. To ensure that you have the right temperature, you will need to have at least a 60 degree rise in the temperature, and your tankless hot water heater should be able to produce 5.2 gallons per minute. You will need to pay close attention to this because under sizing your system will leave you with no hot water to do the things that you need to do.

You will need to determine the flow rates that you need for your hot water heater to ensure that you are able to do the things that you need to do. Do you plan to run two showers at the same time or run several sinks at the same time? It is recommended that you use 1.0 GPM for bathroom water needs. If you are running two different showers at the same time, you will need at least 5 gallons of water from your tankless water heater. If you need to run both your washing machine and shower at the same time, you will use around 4.5 gallons per minute. You will want to make sure that you size your heater accordingly. Determining your usage rates will help you to pick the right tankless water heater for your needs.

If you need to produce a larger water temperature rise per GPM, you may want to consider getting a gas tankless hot water here. These gas hot water heaters are able to increase temperatures quickly.

If you want to learn better on How To Size A Tankless Water Heater, call E Dennis today. They will be able to tell you the water heater size that you need and show you the best options available. They can sit down and go over your usage rates to determine whether or not you would be better off getting an electric tankless hot water heater or gas one. When you hire a professional plumbing company, you will not have to worry about having to install the hot water heater or having to ensure that you have the right size. Water heater installation can be difficult and dangerous, so it is always a great idea to leave it to the professionals.

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