Two common types of gas water heaters are storage – type gas water heaters and tankless (instantaneous) gas water heaters:
- Storage – type gas water heaters
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- Working principle: These water heaters have a large storage tank. Gas is burned to heat the water inside the tank, which is then stored until needed. A thermostat controls the temperature, turning on the gas burner when the water temperature drops below a set point to re – heat the water.
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- Features: They can supply a large amount of hot water at once, making them suitable for households with multiple people who may need to use hot water simultaneously, such as for taking showers, doing laundry, and washing dishes. However, the tank takes up significant space, and there is a limit to the amount of hot water available. Once the stored hot water is used up, users need to wait for the water in the tank to be reheated. Also, since the water is stored for a long time, there is a risk of sediment accumulation in the tank, which may require periodic maintenance.
- Tankless (instantaneous) gas water heaters
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- Working principle: Instead of storing hot water, tankless gas water heaters heat water as it passes through the unit. When a hot water tap is opened, cold water enters the heater, and gas is immediately ignited to heat the water using a heat exchanger. The flow rate of the water and the amount of gas burned are adjusted based on the temperature setting to ensure the water comes out at the desired temperature.
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- Features: They are more compact and space – saving as they don’t require a large storage tank. One of the main advantages is that they can provide an endless supply of hot water, as long as the water flow rate is within the capacity of the unit. They are also more energy – efficient compared to storage – type heaters because they only heat water when it’s needed, rather than keeping a large volume of water hot continuously. However, their heating capacity is limited by the flow rate. In some cases, if multiple hot water appliances are used at the same time, the water temperature may drop as the unit struggles to heat a large volume of water quickly.
Each type has its own set of advantages and disadvantages, and the choice between them depends on factors such as household hot water usage patterns, available space, and energy – efficiency preferences.