Correct sizing of your hot tub's motor, heater and pump is a critical factor which can highly influence the success of your hot tub. Depending on the type of hot tub you own, there may be more than one option when it comes to the sizing of the equipment. You may need the assistance of a qualified professional to help you determine the proper sizing for your specific hot tub model.
There are basically two sizes of pumps for traditional residential hot tubs: 1.5 inch and 2 inch nominal pipe sizes. The 1.5 inch pipes will generally have a circumference of just under 6-inches, whereas 2 inch pipes will generally have a circumference of just over 7-inches. When choosing a pump it is important to consider its capacity in relation to the volume of water in your hot tub, the number of jets and the operating costs.
Motor sizing is usually determined through horsepower. Generally, a 1 horsepower pump motor will be adequate for a hot tub that is between 500 and 700 gallons with approximately 4 hydro jets. A motor with 2 horsepower will also be effective for larger sized tubs, but will also increase the cost of the motor in the process. Generally, most residential hot tub pump motors have a 48 frame high performance with 1 or 2 horsepower motors, depending on the size.
The hot tub heater is quite possibly the most important component of your hot tub. Traditional residential hot tub heaters operate on 230 volt single phase. They are generally available in 4 sizes which include 2, 3, 4 and 5.5 kilowatts. Some manufacturers choose to size their heaters according to BTUs, in which case they are available in sizes between 5000 BTU/hr and 40,000 BTU/hr. The size you choose will highly depend upon the type and size of hot tub you own.
Specific sizes for your hot tub cannot be determined without knowing the size or make of the hot tub you own. These are simple guidelines to follow in order to make sure you know the appropriate question to ask when shopping for your tub. Make sure you ask a professional for their opinion in order to ensure you choose sizes which are compatible with your hot tub.