Water Heating
Every 10 degrees that you lower your water temperature will result in a 3-5% energy savings for your water heating cost. Ideal temperature settings are between 115 and 120 degrees. Most thermostats are inaccurate and some don't even have numbers to go by. To set the temperature you can keep reducing it until you can't go any lower for your household or you can run the hot water until the temperature of the hot water coming out stabilizes, then fill a container with hot water and use an accurate thermometer to read the temperature of the water and make adjustments based on that.
Installing a water heater blanket can save you 4-9% on water heating cost. Never cover the top of a gas water heater because of the flame at the exhaust. There is a rebate for our Georgia Power customers for $30 to install an R-6 or greater blanket on an electric water heater.
Insulate your hot water pipes from the water heater as far as you can. Measure your pipe diameter, usually 1/2" or 3/4" and pick up some pipe insulation and tape at your hardware store. This will keep the water in the pipe hotter longer and reduce the need to purge the line before getting in the shower. Also insulate the first five feet of the cold water line starting at the tank because some heat will be conducted out through the cold water pipe.
Install low flow shower heads. If you use less hot water in the shower that's less water to heat and less water to buy. Read the fine print at the hardware store to make sure what the gallon per minute rating is 2.5 or less which is required to be considered a low-flow shower head.
Check all of the faucets to see if they have 2.75 GPM aerators or less and they can go as low as 0.5 GPM. The number on the side of the aerator is the GPM rating. These sometimes get modified to let more water through so check to make sure that all of the pieces are there and watch it when it operates.
Water heaters have a life span of 10-25 years. New electric heaters have an energy factor of 0.90 and are available up to 0.95. Gas water heaters start at 0.59 and go up to 0.67. Gas water heaters have lower ratings because they waist energy as exhaust but you have to factor in the cost of gas versus electricity to determine which type is more efficient for you. Stainless tank models are available that eliminate all your replacement problems except having to change out an element when they go out.
Heat pump water heaters are catching on. The big box hardware stores have models for around $1,400 and they qualify for the federal and state tax rebates. They are about three times more efficient at making hot water so they will pay for themselves in 5 to 7 years.
Tank less or on demand water heaters are becoming more popular. They only heat the water when its needed, they never run out and they eliminate the standby losses that storage water heaters have. These work better in applications where hot water is not needed as often or on more remote locations or a weekend house.
Solar Heating is a an option that can supplement your water heating needs throughout the year. There are some Federal and State credits available and you need to take a good look at the return on investment because, depending on where you live, the amount of sunlight and factors like trees, it will affect the amount of time it takes to get you investment back. In our area, never disable your heating elements because you will run out of hot water and need to make some. It is common to turn up the thermostat in the winter and turn it down in the summer when there's more sunlight. These work great for heating swimming pool.
Waste heat recovery is available on some heat pump systems. When the air conditioning is running, water from the hot water tank is passed throughout the heat exchanger and waste heat is transferred into the water and back into the hot water tank. This can supply you with most of your hot water needs for free during the summer months.