Water heating is typically the third largest energy expense in your building (after space heating and cooling). It typically accounts for about 14% of your utility bill.
If your gas water heater is more than 10 years old, it probably has an efficiency no higher than 50%. An old water heater can operate for years at very low efficiency before it finally fails. One way to reduce water heating costs would be to replace your old water heater with a new, higher-efficiency model.
About Water Heater Efficiency
A water heater's efficiency is measured by its energy factor (EF). EF is based on recovery efficiency, standby losses, and cycling losses. The higher the EF, the more efficient the water heater. Electric resistance water heaters have an EF ranging from 0.7 and 0.95; gas water heaters from 0.5 to 0.6, with a few high-efficiency models ranging around 0.8; oil water heaters from 0.7 and 0.85; and heat pump water heaters from 1.5 to 2.0.
Although many consumers make water heater purchase decisions based only on the size of the storage tank, the first-hour rating (FHR), provided on the Energy Guide label, is actually more important. The FHR is a measure of how much hot water the heater will deliver during a busy hour. The FHR is required by law to appear on the unit's Energy Guide label. Therefore, before you buy a water heater, estimate your building's peak-hour demand and look for a unit with an FHR in that range. And beware that a larger tank doesn't necessarily mean a higher FHR.
Tips for Buying a New Water Heater
- Choose a water heater with an appropriate first-hour rating (FHR).
- Determine the appropriate fuel type for your water heater. If you are considering electricity, check with your local utility company for off-peak electricity rates for water heating. If available, this may be an attractive option to choose electric water heaters. Natural gas, oil and propane water heaters are less expensive to operate than electric models.
- If you are in a moderate climate (i.e., with relatively low heating loads), consider a Heat Pump Water Heater (HPWH), which is more efficient than a conventional electric water heater. Though a HPWH may have a high initial cost, it can save up to 50% of your water heating bill.
- For safety as well as energy-efficiency reasons, when buying gas- and oil-fired water heaters, look for units with sealed combustion or power venting to avoid back-drafting of combustion gasses.
- Everything else being equal, select a water heater with the highest energy factor (EF). However, you should note that the EF of one type of heater is not comparable to another type. For example, an electric water heater with an EF of 0.9 may cost more to operate than a gas water heater with an EF of 0.7.
- Whenever possible, do not install the water heater in an unheated basement. Also try to minimize the length of piping runs to your bathroom and kitchen.
Tips for Lowering Your Water Heater's Energy Usage
- Repair leaky faucets. A leak of one drip per second can cost $1 per month.
- Insulate your hot water storage tank and pipes, but be careful not to cover the tank thermostat(s).
- Lower the thermostat(s) on your water heater to 120°F. Electric water heaters often have two thermostats-one each for the upper and lower heating elements. These should be adjusted to the same level to prevent one element from doing all the work and wearing out prematurely.
- For electric water heaters, install a timer that can automatically turn the hot water off at night and on in the morning. A simple timer can pay for itself in less than a year.
- Install a heat trap above the water heater. A heat trap is a simple check valve or piping arrangement that prevents "thermosyphoning"-the tendency of hot water to rise up from the tank into the pipes-thereby lowering standby losses.
- Drain a quart of water from your hot water tank every 3 months to remove sediment that prevents heat transfer and lowers the unit's efficiency.
Types of Water Heaters
It's a good idea to know the different types of water heaters available before you purchase one:
- Conventional storage water heaters offer a ready reservoir (storage tank) of hot water
- Tankless or demand-type water heaters heat water directly without the use of a storage tank
- Heat pump water heaters move heat from one place to another instead of generating heat directly for providing hot water
- Solar water heaters use the sun's heat to provide hot water
- Tankless coil and indirect water heaters use a home's space heating system to heat water
When selecting the best type and model of water heater for your building, consider the following:
- Fuel type, availability, and cost. The fuel type or energy source you use for water heating will not only affect the water heater's annual operating costs but also its size and energy efficiency. See below for more on selecting fuel types.
- Size. To provide your building with enough hot water and to maximize efficiency, you need a properly sized water heater.
- Energy efficiency. To maximize your energy and cost savings, you want to know how energy efficient a water heater is before you purchase it.
- Costs. Before you purchase a water heater, it's also a good idea to estimate its annual operating costs and compare those costs with other less or more energy-efficient models..
Also, be sure to do what you can to reduce your hot water use. You may also want to explore other strategies such as drain-water heat recovery to save money on your water heating bill.
Fuel Types, Availability and Costs For Water Heating
When selecting a new water heater, it's important to consider what fuel type or energy source you will use, including its availability and cost. The fuel used by a water heating system will not only affect annual operation costs but also the water heater's size and energy efficiency.
Fuel type and its availability in your area may narrow your water heater choices. The following is a list of water heater options by fuel or energy source:
- Electricity Widely available in the United States to fuel conventional storage, tankless or demand-type, and heat pump water heaters. It also can be used with combination water and space heating systems, which include tankless coil and indirect water heaters.
- Fuel oil Available in some areas of the United States to fuel conventional storage water heaters, and indirect combination water and space heating systems.
- Geothermal energy Available throughout the United States to those who will have or already have a geothermal heat pump system installed for space heating and cooling.
- Natural gas Available in many areas of the United States to fuel conventional storage and demand (tankless or instantaneous) water heaters, as well as combination water and space heating systems, which include tankless coil and indirect water heaters.
- Propane Available in many areas of the United States to fuel conventional storage and demand (tankless or instantaneous) water heaters, as well as indirect combination water and space heating systems.
- Solar energy Available throughout the United States -- most abundantly in the Southwest -- for solar water heaters.
Comparing Fuel Costs and Water Heater Types
If you have more than one fuel type available in your area, it's a good idea to compare fuel costs, especially if you're beginning new construction. Even if you're replacing a water heater, you may find that you'll save more money in the long run if you use a different fuel or energy source. Contact your utility for current fuel costs or rates.
The type of water heater you choose will also affect your water heating costs. One type of water heater may use a fuel type more efficiently than another type of water heater. For example, an electric heat pump water heater typically is more energy efficient than an electric conventional storage water heater.
Also, an electric heat pump water heater might have lower energy costs because of its higher efficiency than a gas-fired conventional storage water heater, even though local natural gas costs might be lower than the electricity rates.
If you are thinking about purchasing a new water heater, please contact TCMS today. We can often leverage our network and relationships to find the equipment you need below the market price.