It appears that there are many reasons for liking energy efficient tankless hot water heaters! I'll review the pros and cons, but you will have to make the final decision as to whether or not they are for you.
Mostly they've a longer life expectancy, save money, save energy, take less space, and have an endless supply of hot water.
First there is the life span. Make sure that you figure this when you're doing your calculations. The life span for a regular hot water tank type heater will probably be about 10 to 12 years. Naturally there are factors that will change that, such as the quality of your water. The life span of a energy efficient tankless water heater will be closer to the 20 year range. And I did find some with a limited lifetime warranty.
There seem to be many numbers floating around as to the actual amount of savings. The energy efficient tankless water heater could be as much as 40% more energy efficient, depending upon who you talk to and your personal use. The conventional water heater keeps water at a constant temperature and is always reheating the water. The tankless, also known as “on demand" type of water heater only heats water when it is called for. Just think of the savings if you went on vacation, or even if you did not normally use hot water for many hours.
The space savings is an additional benefit. Since they are mounted on the wall, they take zero floor space, plus they can be installed closer to the point of use. This gives you a great deal more flexibility when choosing a location. You may also want to consider having more than one. For example, if you had a far away area with little use, you could use a smaller unit. This would take some of the burden off of the main unit, plus put the water closer to where it is needed.
The endless supply of hot water is a big benefit for big. There is nothing worse than being the person in the shower when the hot water runs out! And of course it seems to take forever before there's hot water again.
There may also be a federal tax credit of $300. The water heater would have to have an efficiency rating of .80 minimum to be eligible. They do not all meet this number.
You can also check to find out if you qualify for any state or local incentives or rebates. Go to www.dsireusa.org to find out.
OK, this all sounds good, but what are the disadvantages?
First there is your ground water temperature. If your ground water is very cold, it may take a much bigger unit to do the job. The cooler water affects the flow rate.
Some water heaters need a large venting system. This may make it hard to deal with if you are installing in an older home or business. They are better suited to new construction.
There have been complaints of the time it takes to get hot water to the point of use. I am not sure about your situation, but the only way that I get hot water immediately is if it has already been running. So you may have to wait anyway.
This may not be a do it yourself job. Most water heaters will require licensed installers to keep you from voiding the warranty.
Only you can decide if energy efficient tankless water heaters are best for you. You should contact an installer. He should have a lot of questions about your use, location, ground water temperature, and what you are paying now. He should be able to go over his figures with you and show you how he arrived at his conclusions.
Just remember that they are trying to make sales. Be sure that you are satisfied with the company and the figures. It may be better for you if they sold both types. That way you could see the difference between a newer more energy efficient conventional water heater and the newer energy efficient tankless water heaters!
Bob Willoughby is the publisher of http://EnergyEfficientHomeTips.net .
There are many ways to make your home more energy efficient and save yourself some money at the same time. Visit the web site to learn more about Energy Efficient Tankless Water Heaters