Propane water heating options include technology that is on the cutting edge of energy efficiency, such as condensing tankless water heaters.
By choosing energy-efficient propane water heating systems over standard electric water heaters, you can help your homeowner and building owner clients significantly reduce their energy costs. The Department of Energy estimates that approximately 20 percent of a home's energy costs are spent heating water. That's why helping your homeowner select an efficient water heater is critical — and propane fuels some of the most efficient tankless water heating technologies available.
Tankless water heaters
Propane tankless water heaters provide comfort, versatility, convenience, and efficiency. Here are a few facts you should know.
- Tankless water heaters deliver an endless supply of water.
- Their compact size saves roughly 12 square feet of floor space.
- These systems are on-demand, so they heat water only when it's needed. That feature eliminates standby losses that occur in systems with hot water storage tanks — like the typical electric water heater.
- They save more than $150 per year in energy costs compared with typical electric storage water heaters.
- They have 50 to 60 percent lower CO2 emissions compared with electric storage tank systems.
- Propane tankless systems also qualify for tax credits and rebates, which can make them even more cost-effective.
Building Science Videos
Check out our slideshow of water heating videos below. In a three-part series, Building Science visits Rinnai to learn the science and innovations behind tankless water heating.
Storage tank water heaters
Compact in size and equipped with leading features such as electronic ignition and highly insulated tanks, Energy Star–qualified propane storage tank water heaters offer superior value to comfort-seeking homeowners. Here are a few features you should know about.
- A propane storage water heater delivers the same amount of hot water as an electric tank, which is much larger and takes up more space in the home.
- Propane storage water heaters are eligible for Energy Star qualification, whereas electric resistance units and heating oil units are not.
- Energy Star propane units save about 13 to 16 percent in annual energy costs over standard electric and heating oil units.
- Propane storage tank water heaters offer CO2 emissions reductions of 1,900 pounds per year, compared with standard electric units.
Propane fuels a number of other innovative water heating technologies, such as hybrid/tankless solar hot water systems and combination units that combine space heating and water heating. See the results of our study that compares different water heating systems on the basis of economics, efficiency, and performance.
Watch a video case study of a storage electric water heater being replaced by a high-efficiency propane storage unit.
Commercial tankless water heating
Propane tankless systems can also be banked together in larger groups or racks to satisfy higher demands for commercial buildings. A rack of six tankless units could deliver up to 30 gpm with a rise of 70 degrees Fahrenheit. Innovations such as factory-assembled racks of units and shared venting expedite field installation time and reduce costs. Sophisticated controls, valves, and pumps cycle the banked units to spread the usage evenly, provide redundancy in case one unit needs to go offline for service, and ensure steady delivery of hot water across a wide range of flow rates.
These innovations drive significant energy cost savings from tankless designs. Hot water energy costs using condensing tankless systems can be as little as half those of electric storage tank units. Tankless systems' cost-effectiveness, as well as their reliability and redundancy, are very attractive in buildings with significant hot water usage. For example, more than 100 Chili's restaurants in the Northeast use banks of tankless water heaters. An informal survey of the installation at one Chili's location revealed savings of roughly $1,800 per year in energy costs, although the improved reliability was the main factor driving the decision to go tankless.
Commercial storage tank water heaters
Another high-efficiency option for water heating in commercial buildings is a propane high-volume water heater. High-volume commercial propane water heaters have high output capacities well suited for the high-demand applications often found in restaurants, hospitality, and health care. Sizes can range from units less than 200 kBtu/hour up to 1,000 kBtu/hour or higher, with flow rates from 4 to 20 gpm (at a rise of 70 degrees Fahrenheit) for a single unit.
Propane storage tank water heaters work well in many commercial applications, offering the following advantages:
- Faster recovery rates compared with electric storage tank units.
- Scalable to meet a wide range of hot water demands.
- Generally lower operating costs compared with heating oil or electric storage tank units.
- Smaller gas/propane line compared with tankless units that often require a larger line.
- Easily adapted to re-circulation applications, which are increasingly common designs to save energy and water and expedite hot water delivery.
- Resist hard water complications better than electric heaters.
- Easy integration into solar hot water systems as a storage and back-up heating component.