The answer to 'tankless vs tank water heater which is better' is that tankless water heaters are generally more energy-efficient and cost-effective in the long run compared to traditional tank water heaters. Tankless heaters heat water on-demand rather than constantly maintaining a full tank, which can save homeowners up to 50% on their water heating bills. They also take up less space and have a longer lifespan of 20+ years.
However, tankless models have a higher upfront cost and may require electrical or gas upgrades to the home, which can add to the installation expense. Tank water heaters are often more affordable to purchase and install, especially in older homes. They also provide a continuous supply of hot water, unlike tankless which can run out during periods of high demand.