New Water Heater Sizes You Need For Your Home[2021]

Properly running sizes water heaters will meet the hot water needs of your home while running more efficiently. So, before buying a water heater, make sure it is the right size.

Here you will find information about the size of these systems:

  • Water heaters size like tankless or on-demand.
  • Solar water heating system.
  • Storage and heat pump (with tank) Water heater.

A combination of water heater size and space -. These include some heat pump systems, and tankless coils, and indirect water heaters. – Consult a qualified contractor.

If you have not yet considered what type of water heater might be best for your home, find out more about choosing a new water heater.

Tankless or demand-type water heater.

Tankless or demand-type water heaters are rated for the maximum temperature rise at the rate of temperature rise. Therefore, to size the demand water heater, you need to detect the increase in flow rate and temperature so that you can apply it in your home (complete home or remote application, such as just one bathroom). ) Is required.

First, list the number of hot water devices you can expect at a given time. Then, add their flow rate (gallons per minute). This is the required flow rate that you can get from Demand Water Heater. For example, let’s say you have a simultaneous flow rate of 0.75 gallons (2.84 liters) and a showerhead with a flow rate of 2.5 gallons (9.46 liters) per minute. Will run The demand water heater’s flow rate will require a minimum of 3.25 gallons (12.3 liters) per minute. Install low water, low flow water fixtures to reduce the flow rate.

To determine the temperature rise, subtract the temperature of the incoming water from the desired output temperature. Unless you know otherwise, suppose the incoming water temperature is 50ºF (10ºC). For most uses, you’ll want to heat your water to 120ºF (49ºC). You will need a demand water heater that rises to 70ºF (39ºC) for most uses in this example. For dishwashers without internal heaters and other such applications, you want to heat your water to 140ºF (60ºC). In this case, you will have a 90ºF (50ºC) increase in temperature.

Most in-demand water heaters are classified for multiple inlet temperatures. In general, it is possible to increase the water temperature by 5 gallons per minute with gas-powered demand water heaters and 2 gallons per minute by electricity. High flow rates or cold indoor temperatures can sometimes lower the water temperature at extreme distances. The heating system controls some types of tankless water heaters. They can vary their output temperature according to water flow rate and indoor temperature.

Installing a solar heating system.

The size of your solar water heating system basically involves determining the collector’s storage and storage volume, which you must meet 90% of your domestic hot water requirement during the summer. Solar contractors use worksheets and computer programs to help determine system requirements and collector sizes.

Collector Area.

Contractors typically follow guidelines for the first two family members to collect about 20 square feet (2 square meters) of collector area. For each additional person, add 8 square feet (0.7 square meters) if you live in North America if you live in the American Sunshine Belt area or 12 or 14 square feet.

Storage volume

A small (50-60 gallon) storage tank is usually enough for one to two or three people. The medium (80 gallons) storage tank works well for three to four people. A large tank is suitable for four to six people.

For functional systems, the size of the solar storage tank increases with the collector’s size – typically 1.5 gallons per square foot of collector. When the demand for hot water is low, it helps the system avoid overheating. In extremely hot, sunny climates, some experts suggest that the ratio should be kept at 1 square foot for maximum storage of 2 gallons.

The second calculation of Water Heater Sizes.

Additional calculations involving the size of your solar water heating system include reviewing the solar resources at your building site and determining the solar collector’s appropriate direction and inclination. For more information on these calculations, visit the Solar Water Heater page.

Water heat measurement and heat pump (with tank)

To properly size a storage water heater for your home – including a tank-pumped water heater – use the water heater’s first-hour rating. The first-hour rating is the number of hot water gallons a heater can deliver per hour (starting with a hot water tank). It depends on the tank’s capacity, the heat source (burner or element), and the amount of burner or element.

The Energy Guide label in the top left corner lists the first-hour rating as “Capacity (First Hour Rating). The Federal Trade Commission requires energy guide labels on new traditional storage water heaters but not on heat pump water heaters.” No. Manufacturer’s Product Literature can also provide first hour ratings. Find the first hour rated water heater size that matches your peak hour demand by 1 or 2 gallons.

To estimate your high time demand:

  • Decide at what time of day (morning, afternoon, evening) you use the hottest water in your home. Keep in mind the number of people living in your home.
  • Use the worksheet below to estimate the maximum use of hot water during this one hour of day peak. 

hot water demand worksheet

This is your high time demand. Note: The daily hot water usage is not estimated in the worksheet.

The worksheet example shows the demand for a total of 36 demands. Therefore, this home will need a water heater size with a first-hour rating of 34 to 38 gallons.

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