When you're ready for a new water heater you'll want to research all your options and choose the best appliance for your home and situation. Read below to see what type might be right for you.
- Conserve Water - Your biggest opportunity for savings is to use less hot water. In addition to saving energy and money, cutting down on hot water use helps conserve dwindling water supplies, which in some parts of the country is a critical problem. A family of four each showering five minutes a day can use about 700 gallons per week—a three-year drinking water supply for one person! Water-conserving showerheads and faucet aerators can cut hot water use in half. That family of four can save 14,000 gallons of water a year and the energy required to heat it. For a limited time, you can get a Free conservation kit from City Hall that includes a high efficiency showerhead, along with many other items that can help you save energy (and money) at home.
- Insulate Your Existing Water Heater - Is your water meter warm to the touch? That means it is losing heat and wasting money. Installing an insulating jacket is one of the most effective do-it-yourself energy-saving projects, especially if your water heater is in an unheated space. The insulating jacket will reduce standby heat loss—heat lost through the walls of the tank—by 25–40%, saving 4–9% on your water heating bills. Water heater insulation jackets are widely available for around $10. Always follow directions carefully when installing an insulation jacket.
- Insulate Hot Water Pipes - Insulating your hot water pipes will reduce losses as the hot water is flowing to your faucet and, more importantly, it will reduce standby losses when the tap is turned off and then back on within an hour or so. A great deal of energy and water is wasted waiting for the hot water to reach the tap. Even when pipes are insulated, the water in the pipes will eventually cool, but it stays warmer much longer than it would if the pipes weren’t insulated.
- Lower the Water Heater Temperature - Keep your water heater thermostat set at the lowest temperature that provides you with sufficient hot water. For most households, 120°F water is fine (about midway between the “low” and “medium” setting). Each 10°F reduction in water temperature will generally save 3–5% on your water heating costs. When you are going away on vacation, you can turn the thermostat down to the lowest possible setting, or turn the water heater off altogether for additional savings. With a gas water heater, make sure you know how to relight the pilot if you’re going to turn it off while away.
- Install Heat Traps on the Water Heater Tank - If your storage water heater doesn't have heat traps, you can save energy by adding heat traps to your water heating system. They can save you around $15–$30 on your water heating bill by preventing convective heat losses through the inlet and outlet pipes. Heat traps—valves or loops of pipe—allow water to flow into the water heater tank but prevent unwanted hot-water flow out of the tank. The valves have balls inside that either float or sink into a seat, which stops convection. This is best installed by a professional plumbing and heating contractor.
- Install a Timer and Use Off-Peak Power for Electric Water Heaters - If you have an electric water heater, you can save an additional 5%–12% of energy by installing a timer that turns it off at night when you don't use hot water and/or during your utility's peak demand times. You can install a timer yourself. They can cost $60 or more, but they can pay for themselves in about 1 year. Timers aren't as cost effective or useful on gas water heaters because of their pilot lights.
- Drain-Water Heat Recovery - Any hot water that goes down the drain carries away energy with it. That's typically 80–90% of the energy used to heat water in a home. Drain-water (or greywater) heat recovery systems capture this energy to preheat cold water entering the water heater or going to other water fixtures. Drain-water heat recovery technology works well with all types of water heaters, especially with demand and solar water heaters. Also, drain-water heat exchangers can recover heat from the hot water used in showers, bathtubs, sinks, dishwashers, and clothes washers. Check with your local building code to see if this is possible.
It's generally easier to move something than to make something. Putting that principle to use, HPWHs use electricity to move heat from one place to another instead of generating heat directly.
To understand the concept of heat pumps, imagine a refrigerator working in reverse. While a refrigerator removes heat from an enclosed box and expels that heat to the surrounding air, a HPWH takes the heat from surrounding air and transfers it to water in an enclosed tank.
During periods of high hot water demand, HPWHs switch to standard electric resistance heat (hence they are often referred to as “hybrid” hot water heaters) automatically. HPWH come with control panels that you to select from different operating modes, which include:
- Efficiency/Economy – Maximizes energy efficiency and savings by only using the heat pump to heat water
- Auto/Hybrid – The default setting is ideal for daily use, providing energy-efficient water heating with sustained heat
- Electric/Heater – This high-demand setting is the least energy-efficient, using only the electric element to heat water
- Vacation & Timer (not available on all models) – Save on your energy when away from home by placing the unit in "sleep" mode until you return
Login to the SCPWChallenge to learn more about Heat Pump Water Heaters and locally available incentives.
Info source: ENERGY STAR
High-efficiency gas storage water heaters employ the same technology as standard gas storage water heaters: a glass-lined steel tank is heated by a burner located at the bottom of the tank. But a few basic changes make them operate more efficiently. Many ENERGY STAR certified models simply have better insulation, heat traps, and more efficient burners, improvements that have a modest impact on price lead to 8% less energy use. Some very high efficiency models use a secondary heat exchanger that extracts more heat from the combustion gas, cooling it to the point where there is condensation– hence these types of heaters are called “gas condensing.” These gas condensing water heaters, like gas condensing furnaces, require venting through a vertical PVC pipe and a condensate drain.
Info source: ENERGY STAR
Whole-home gas tankless water heaters apply the same principle to heat water as standard gas water heaters, but without a storage tank. They save energy by heating water only when needed, eliminating energy lost during standby operation. When a hot water tap is turned on in the home, cold water is drawn into the water heater. A flow sensor activates the gas burner, which warms the heat exchanger. Incoming cold water encircles the heat exchanger and leaves the heater at its set-point temperature. Combustion gases safely exit through a dedicated, sealed vent system. By heating water only when needed, instead of maintaining a tank full of hot water at all times, tankless water heaters can achieve greater efficiency than standard tank-type water heaters.
An ENERGY STAR certified gas tankless water heater uses a secondary heat exchanger to use 9 percent less energy than a conventional gas tankless water heater. The secondary heat exchanger extracts more heat from the combustion gas, cooling it to the point where there is condensation – hence these types of heaters are called “gas condensing.” These gas condensing tankless water heaters, like gas condensing furnaces, require venting through a vertical PVC pipe and a condensate drain.
Info source: ENERGY STAR
Solar water heaters come in a wide variety of designs, all including a collector and storage tank, and all using the sun's thermal energy to heat water.
Solar water heaters are typically described according to the type of collector and the circulation system.
Flat-plate collectors typically consist of copper tubes fitted to flat absorber plates. The most common configuration is a series of parallel tubes connected at each end by two pipes, the inlet and outlet manifolds. The flat plate assembly is contained within an insulated box, and covered with tempered glass. Flat plate collectors are typically sized to contain 40 gallons of water. Two collectors provide roughly half of the hot water needed to serve a family of four.
Evacuated tube collectors are the most efficient collectors available. Each evacuated tube is similar to a thermos in principle. A glass or metal tube containing the water or heat transfer fluid is surrounded by a larger glass tube. The space between them is a vacuum, so very little heat is lost from the fluid. These collectors can even work well in overcast conditions and operate in temperatures as low as -40°F. Individual tubes are replaced as needed. Evacuated tube collectors can cost twice as much per square foot as flat plate collectors.
Batch collectors, also called Integrated Collector-Storage (ICS) systems, heat water in dark tanks or tubes within an insulated box, storing water until drawn. Water can remain in the collector for long periods of time if household demand is low, making it very hot. A tempering valve is your protection from scalding at the tap. The tempering valve mixes in cold water to decrease the water's temperature before it's delivered to the tap. Batch collectors are incompatible with closed-loop circulation systems. Thus, they are generally not recommended for cold climates.
As an incentive, Park City waives building permit fees for installing solar water heaters and has modified code to make them as permissible as possible.
Info source: ENERGY STAR