Final answer:
Line sets for residential split systems are commonly sold in lengths such as 15, 20, 30, and 50 feet to fit various home layouts and are used with electric heat pumps for heating and cooling.
Step-by-step explanation:
Line sets for residential split systems, which include houses equipped with electric heat pumps for cooling and heating applications, typically come in several standard lengths. Common lengths available are 15 feet, 20 feet, 30 feet, and 50 feet, which helps to accommodate different sizes and layouts of residential spaces. It's important to select the proper length needed for the specific setup to ensure efficient operation of the heating and cooling system.