Water heaters are essential components of HVAC systems that provide hot water for showers, sinks, and other uses. They typically use either gas or electric power to heat the water, with gas models being more energy efficient and cost-effective in the long run. Water heaters come in various sizes and capacities to suit a variety of needs, from small tankless units to large tanks with capacities of up to 80 gallons. Many modern models also feature advanced features such as temperature control, timer settings, and energy efficiency ratings. With proper maintenance and installation, water heaters can last for many years while providing reliable hot water service.