The third largest energy user in your home, after heating and cooling, is your home’s hot water heater system. According to the U.S. Department of Energy between 15- 25% of each energy dollar a homeowner spends goes to heat water.
It makes sense when you consider that the average family uses between 350-400 gallons of water a day, and about 70% of this is likely used indoors. Of that a little under half is estimated to be hot water, which brings us to around 120 gallons of hot water a day for a family of four. We use it for our hot showers, baths, dishwashers, washing machines and a myriad of other ways. (One of my horse loving friends bathes her horse for shows using hot water – that's a lot of gallons!)
Time to Replace your Hot Water Heater System?
Since the average traditional hot water heater system has a life of about 8-12 years if it's powered by gas and 10-15 years if powered by electric, it's pretty likely you'll be replacing a hot water heater system at least once or twice along the way. It might be the right time to think green about your hot water heater system. But you'll have to do an evaluation first.
Start by figuring out what size hot water heater system you need for your home. How much hot water does YOUR home use, on average in a day? Buying a hot water heater system that is too large can be as costly as buying a hot water heater system that's too small.
Then consider your location and your available energy source. Can your environment support a green solar hot water system, or are you living in an area where gray days outnumber sunny ones, in which case you might need a combination system?
On the cost side, what you'll pay for hot water depends on climate, type of system, your source of power, and your overall usage. Here's a look at various hot water heater systems:
What are your Hot Water Heater System Options?
- Conventional storage heaters require a tank, which holds the ready reserve of hot water and can be powered by electricity, natural gas, propane, and fuel oil. Water is constantly heated by these heaters even when your tap water isn’t running, resulting in wasted energy known as ‘standby heat loss'. While a conventional storage hot water heater system may cost less than the other heater systems to purchase and install, they generally cost more to operate and maintain over the heater’s lifetime.
- Demand, tankless or instantaneous, water heaters provide water when a hot water tap is turned on or ‘on demand', avoiding standby heat loss. Powered by electricity, natural gas, or propane, the flow rate of the delivered hot water is lower than that of a conventional storage heater which could result in a shortage of hot water when you need it. EnergySavers.gov reports that demand water heater can be 24%-34% more energy efficient than a conventional storage tank hot water heater system for homes that use 41 gallons or less of hot water daily. Since we estimated a 120 hot water use for the average family per day, this may not be the best option for all homes.
- Heat pump water heaters are powered by heat pumps through electricity. The pump can be used to heat water as stand-alone water heating units or as combination home heating and hot water heater system. The purchase price and installation cost of a heat pump hot water heater system is higher than the cost of a conventional storage water heater. However, higher purchase and installation costs for a heat pump system can be offset by lower operating costs. Heat pumps can be retrofitted to work with your existing conventional storage water heater and then your conventional system becomes a more efficient system.
- Tankless coil and indirect water heaters work off your main furnace’s or boiler’s installed heating coil or heat exchanger. Hot water flows through the heat exchanger as the hot water faucet is turned on, demanding hot water, similar to the demand hot water heater system. It's most efficient if regularly used during cold weather but not as efficient in warmer climates.
- The solar hot water heater system can be used in any climate and is powered by our naturally free sunlight. With a solar hot water heating system your heating bills could drop 50% to 80%. Plus you avoid the consequences of fuel shortages and price increases because your hot water heater’s energy source, sunlight, is free. The purchase and installation costs of a solar hot water heater system usually are more than a conventional hot water heating system, but you likely can qualify for Federal and State tax credits for consumer energy efficiency.