If you’ve ever been the last person in your household to shower and found yourself shivering under a stream of lukewarm water, you have experienced the primary limitation of the traditional hot water storage tank. For decades, the insulated tank was the standard, but modern technology has shifted toward a more sophisticated alternative: the tankless, or “on-demand,” water heater. By heating water only when it is needed, these units offer significant advantages in space, efficiency, and performance.
Unmatched Space Efficiency
Tankless Water Heater stored in closet
One of the most immediate benefits of switching to a tankless system is the reclamation of floor space. A traditional water heater is essentially a massive, 50-to-80-gallon drum that typically occupies 15 to 20 square feet of valuable real estate in a basement, garage, or utility closet.
In contrast, a tankless unit is roughly the size of a carry-on suitcase. Because it lacks a reservoir, it is wall-mounted, freeing up the entire floor area beneath it. This compact design allows for installation in non-traditional locations, such as under a kitchen sink, inside a small pantry, or even on an exterior wall. In a world where space is becoming increasing valuable and expensive, the far smaller footprint of a tankless heater is undeniably superior.
Superior Energy Efficiency
Traditional heaters suffer from a phenomenon known as standby heat loss. Because the tank must keep 50 gallons of water at a consistent 120°F (or higher) 24 hours a day, the heating element or burner must cycle on repeatedly—even while you are asleep or at work. This is essentially paying to heat water you aren’t using. On a weeklong vacation, a traditional tank water heater will heat the same water again and again each time it cools below the pre-set temperature level, which is highly energy inefficient.
Tankless units eliminate this waste. They only consume energy when a hot water tap is opened. According to the U.S. Department of Energy, tankless water heaters can be 24% to 34% more energy-efficient than traditional tanks for households using average amounts of hot water. Over the 20-year lifespan of the unit, these energy savings can significantly offset the higher initial purchase price many times over.
Limitless Throughput and Performance
Principle of a Tankless Water Heater
The most celebrated feature of a tankless system is its throughput capacity. In a traditional setup, once you use the capacity stored in the tank, you must wait upwards of an hour for the unit to recover and heat a fresh supply of cold water.
Tankless heaters provide a continuous flow of hot water. As long as there is a supply of energy(gas or electricity) and water, the unit will continue to produce heat. While the “flow rate,” measured in Gallons Per Minute (GPM), is limited by each unit’s power, it will never “run out” in the middle of a shower. This makes tankless systems ideal for large families or homes with high-volume fixtures like luxury soaking tubs.
Water Quality & Durability
After about 10 years the resident water in a standard tank water heater will cause rust in the tank, which will appear in the water from it. Because there is no water sitting in a tankless unit it will not rust and will typically last twice as long as a standard tank water heater.
If you would like your New England building designed to not only be more comfortable but also more sustainable and energy efficient, please reach out to the award-winning professionals at A4 Architecture and we will be pleased to help you achieve your project’s goals.
Ross Cann, RA, AIA, LEED AP, is an author, historian, and practicing architect living and working in Newport, RI. He holds degrees with honor in Architecture from Yale, Cambridge, and Columbia Universities. He studied Molecular Biophysics as an undergraduate at Yale and understands the science just as well as he understands the aesthetics of creating a beautiful and functional buildings.