A 3kw solar photovoltaic power system could optimally generate 5500kwh/year. The system cost $20,000 to 30,000 installed. Government assistance is $12000 per system. 22 cents per kwh for ten years. Water heaters that are twice as efficient would have 2400 kwh/year and government payment of the $2400 price difference over standard water heaters would be 10 cents per kwh for ten years. Even full payment of $3000 for would be 12.5 cents per kwh for ten years and volume purchase agreements and high volume production could reduce the costs. For the price the government pays for one solar PV home, there could be 5-6 homes saving half of the energy generated by that one solar PV system. This does not include the extra cost paid by the home owner. The homeowner and the government combined pay $21,000 for solar versus $3500 for a twice as efficient water heater. The water heater option is usually 300% more efficient than solar power (About 300% in sunny California, Nevada and even more effective in places with less sunlight).
The Department of Energy’s announced April 1, 2008 ENERGY STAR® criteria for residential water heaters. There are and will be more energy efficient water heating products on the market. These will payback for you if you get the tax breaks and utility breaks to help pay for the installation and have average or higher water usage.
Grand Hall brings tank and tank-less technologies together in the first of its kind Eternal® Hybrid water heater (2006). Grand Hall's website is here
The MSRP/retail is $2500-2800 for the different Grand Hall units. The plumber will add an installation charge to a wholesale price. They are available across the United States now and have been installed. This is fairly expensive but it would be less expensive than installing solar panels on your roof to generate the power for an inefficient water heater and other appliances. A 2.4 KW residential system in Los Angeles area and makes estimated output of 3,646 kWH/year (less sunny places produce less electricity. One person online quotes $20,000 to buy and install a 3KW system which was $8000 after rebates and tax breaks
Many solar PV 3KW systems costs $25000-30,000 before rebates.
A GE tankless gas water heater could help homeowners save up to 25 percent annually on water heating costs compared to the operating costs of a standard 40-gallon gas tank water heater.
Available May 1, 2008, the GE Tankless Gas Water Heater will be offered in two sizes (7.5-gallon-per-minute flow and 9.4 gallon-per-minute flow), indoor and outdoor. The 7.5-gallon-per-minute flow will be available for natural gas; the 9.4-gallon-per-minute flow will be available for natural gas or LP gas.
Expect a new GE Hybrid Electric Water Heater in the fourth quarter of 2009. It will use less than half of the energy – or about 2300 kWh per year – a savings of approximately 2500 kWh per year. This wil save approximately $250 per year, and $2,500 savings in energy costs over a 10 year period based on 10 cents per kWh.
Switching the water heater would save more energy than changing all light bulbs in a house with heavy light usage.
DOE Energy Efficiency and Renewable Energy has a consumer guide to Estimating a Solar Water Heater System's Cost. Water heating can account for 14%–25% of the energy consumed in your home.
DOE Energy Efficiency and Renewable Energy has a consumer guide to Estimating a Storage, Demand, or Heat Pump Water Heater's Costs
To lower your water heating bills, try one or more of these energy-saving strategies:
-Reduce your hot water use ( quality, low-flow fixtures for around $10 to $20 a piece and achieve water savings of 25–60%.)
-Lower your water heating temperature (For each 10ºF reduction in water temperature, you can save between 3%–5% in energy costs.)
-Insulate your water heater tank ($10-20, saves 4%–9% in water heating costs)
-Insulate hot water pipes (Insulate all accessible hot water pipes, especially within 3 feet of the water heater. It's also a good idea to insulate the cold water inlet pipes for the first 3 feet.)
-Install heat traps on a water heater tank (A pair of heat traps costs only around $30 and can save $15–$30 on your water heating bill. New units should already have heat traps)
-Install a timer and use off-peak power for an electric water heater
-Install a drain-water heat recovery system.
-If you haven't already, you can save energy and money by installing a more energy efficient water heater
I had previously reviewed a study on cost effient ways to achieve optimum home energy usage
There are 96.7% efficient home energy furnaces.
An independent analysis of electric tankless water heaters.
It costs about $1,200.00 labor and device to install an electric tankless heater, providing you have enough capacity in your electric panel. It costs approximate installed cost of $ 600.00 for a standard electric water heater. Tankless heaters have a life expectancy of 14-18 years a standard water heater will last 6-12 years depending on the hardness of the water and the maintenance performed on it.
Government figures now say the average elctric bill allocates about 13 percent to heat water, so if your monthly bill is about $100.00 your savings might be 3-6.00 per month. Additionally, taking a shower and washing the dishes or clothes at the same time will probably stretch the capabilities of the electric tankless heater. So you will need to not shower and use the washers at the same time to achieve the savings. Many energy bills are higher at $200-400/month.
Tankless system Hybrid system
Extra cost $600 about $2100
$100/mth savings $3.3 $7
Simple payback 15 years 30 years
Utilities often provide bonus savings for reducing energy bill
Extra cost $1000 about 2400
$200/mth savings $6.5 $14
Simple Payback 13 years 14 years
$400/mth savings $13 $28
Simple payback 6.5 years 7 years
Tax breaks for energy efficiency.
Gas, oil, propane water heater Energy Factor 0.80 $300
Electric heat pump water heater Energy Factor 2.0 $300
PGE only provides a $30 rebate for an energy efficient water heater.
Savings analysis from a vendor of tankless water systems If you use a lot more water than average then more costs can be saved.
Electricity costs in the United States by state.
Electric water heating accounted for over 100 billion kWh (9 percent) in 2001. Of the total of 107 million households, 41 million used electricity as their water heating fuel, compared with 58 million households that used natural gas.
Ecogeek talked about the GE tankless and hybrid water heaters and other high efficiency water heaters being able to "kill 30 coal plants" There are 661 sites with almost 1500 coal plants in the United States. Just like hybrid cars it will take a long time to get new efficient models adopted and installed. Probably about ten years if more agressive policies are put in place to encourage faster adoption. Bigger rebates and tax breaks and some formalized means of recovering the savings when houses that are more energy efficient are sold.