Is the Btu rating of a pool heater input gas or transfered going into water?

The Btu rating of a pool heater is the amount of heat energy that the heater can transfer from the combustion of gas to the pool water in one hour. It is measured in British thermal units per hour (Btu/h).

Here's how the Btu rating of a pool heater works:

1. Input Gas: The Btu rating of a pool heater is based on the amount of gas it consumes per hour. The higher the Btu rating, the more gas the heater will use.

2. Combustion: The gas burned in the heater's burner generates heat energy. This heat energy is then transferred to the pool water through the heat exchanger.

3. Heat Exchanger: The heat exchanger is a component of the pool heater that allows the heat energy from the combustion of gas to be transferred to the pool water. The heat exchanger is made of a metal that conducts heat well, such as copper or stainless steel.

4. Pool Water: The heat energy from the heat exchanger is transferred to the pool water as it circulates through the pool heater. The heated pool water then returns to the pool, raising the overall temperature of the water.

So, the Btu rating of a pool heater represents the amount of heat energy that the heater can transfer from the combustion of gas to the pool water in one hour. It is a measure of the heater's heating capacity.