High-efficiency Hot Water Heating

Water heating is the second most expensive energy use in most homes, after central air conditioning and heating.

Floridians are used to seeing their electric bills go through the roof during July, August and September and don’t need to be told that air conditioning uses a lot of electricity. But while you may use hardly any air conditioning during March, April and November, those two big 4,500-watt heating elements in your water heater are burning away every day of the year. At today’s typical Florida electric rates (including fuel surcharges and utility taxes) of around 12–14 cents per kilowatt hour, water heating can easily cost $800 to $1,200 each year for a three to five person household.

We can help you cut this part of your bill by as much as 80%. Options include solar water heating, tankless water heaters, and high efficiency heat pump water heaters.

Hot Water Facts

Energy guzzler. Water heating is the second largest energy user in the average home. Only central air conditioning uses more energy.

History. Miami had 60,000 solar water heaters during the 1940s. What happened? Really cheap electricity and utility company “All-Electric Living” promotions. Florida Power & Light gave away electric water heaters to get homeowners to switch from natural gas, as part of their “Gold Medallion All-Electric Living” program.

Carbon bigfoot. Everyone is concerned about their carbon “footprint” these days. Well, a home water heater’s carbon footprint is a whopper. How big, you ask? Using electricity from an electric utility powerplant to heat 80 gallons of water from 72°F to 140°F each day for one year sends almost four tons of carbon dioxide emissions into Earth’s atmosphere.¹ Yes, really.

Is your hot water use average?

Probably not. An active American family of four is probably closer to 100 gallons per average day and just over $1,000 per year at 14 cents per kilowatt-hour. Here is an example that shows how a four-person household can easily use 100 gallons of hot water per day:

• three people take a typical eight-minute shower every day; the fourth showers 12 minutes for a longer shampoo and rinse: (4 showers × 2 gallons per minute × 8 minutes × 80% hot water) + (1 shower × 2 gallons per minute × 4 extra minutes × 80% hot water) = 57 gallons per day
• five loads of laundry per week; for example, one load each of whites, darks, towels, sheets, and blue jeans: 5 clotheswasher loads × 32 gallons per load ÷ 7 days = 23 gallons per average day
• At least four face and hand washings × 1 gallon per minute × 4 minutes each × 80% hot water = 13 gallons per day
• few sit-down meals because everyone is constantly on the run, so the automatic dishwasher is only run twice per week: 2 automatic dishwasher loads × 14 gallons per load ÷ 7 days = 4 gallons per average day
• One shave × 1 gallon per minute × 2 minutes = 2 gallons per day
• Hand-rinse dishes once a day × 1 gallon per minute = 1 gallon per day

If you happen to have small children, each bath averages about three gallons less hot water than a shower. However, if you happen to have two active teenagers, each taking two showers a day and perhaps creating two or three extra loads of laundry per week, the total can easily jump to over 120 gallons per day.Heating 120 gallons per day from 72°F to 140°F, at 15 cents per kilowatt-hour, costs about $115 per month. Surprised?

Go green and save big dollars.

An active family of four, with five loads of laundry per week, each averaging one shower a day, plus other typical uses, needs about 700 gallons of hot water per week. At today’s electric cost of about 15 cents per kilowatt-hour—which includes taxes and fees—this can cost you over $1,000 a year. With the thermostat set at 140°F, your electric water heater can easily cost you about $250 per family member per year—and that’s assuming you don’t take extra showers—for example, after exercise—or do extra loads of laundry.

Solar water heaters offer many extra benefits.

Naturally, switching to solar water heating means going green in a big way. but you might also be surprised to learn that solar water heating gives you benefits that improve upon conventional electric or gas water heaters:

• More hot water. Most electric water heaters hold enough hot water for about 20 minutes of continuous use. Then the electric element reheats another tankful. You can run out of hot water if two people are showering at the same time, or if you take a shower after the clothes washer or dishwasher have been running. Solar storage tanks are sized to store an entire 24 hour’s worth of hot water because there is no sunshine at night. But this gives you the added benefit that you are less likely to run out of hot water when there are multiple uses at the same time.
• Hotter water. The water delivered by a solar collector panel can be hotter than the thermostat setting on your electric water heater. This means you will have hotter water for the dishwasher and for showers if you you want it. (A mixing valve on the storage tank protects you against scalding.)
• Plenty of hot water during emergencies. With a passive solar water heater, or a system with a solar-powered circulating pump, you will have your customary supply of hot water even during electric power outages. This is an important feature even if you have a standby power generator, because standby generators are not typically sized to handle the power consumption (4,500 to 9,000 watts) of a conventional electric water heater.