The better vertical water heater in the United States is typically the tankless model. Tankless water heaters, also known as on-demand water heaters, provide hot water instantly and only when needed, which is more energy-efficient than traditional storage tank water heaters. According to the U.S. Department of Energy, tankless water heaters can save homeowners up to 24% on their water heating bills compared to conventional storage tank models.

The efficiency of tankless water heaters is attributed to their design. They heat water on demand, which means there is no need to maintain a large tank of hot water, reducing standby energy losses. Additionally, tankless water heaters can be installed in smaller spaces, making them ideal for homes with limited space. According to the Energy Star program, tankless water heaters can last up to 20 years, which is significantly longer than the average lifespan of a storage tank water heater.

Moreover, tankless water heaters offer greater flexibility in terms of installation. They can be installed almost anywhere in a home, including in attics, crawl spaces, and outdoors. This flexibility allows for better customization of the water heating system to meet the specific needs of a household. According to a study by the Lawrence Berkeley National Laboratory, tankless water heaters can reduce peak electrical demand by up to 30%, which is particularly beneficial in areas with high electricity costs.

In conclusion, tankless water heaters are the better choice for vertical water heaters in the United States due to their energy efficiency, longer lifespan, and installation flexibility. These benefits make them a cost-effective and environmentally friendly option for homeowners looking to upgrade their water heating systems.