Is a tankless water heater more efficient and cheaper to operate than a conventional tank water heater?

Question

I am looking into pruchasing a tankless water heater but do not want to pay more to operate it than the tank i have now. I know my tank runs on 1000 btu's and most tankless heaters run at about 10 thousand. Is it worth it to switch over?

Answer 1

Your install investment will be high, it will take 4 to 7 years to recoup the investment from operation. If you can afford the tankless system, it is a better option.

The tankless system is less costly to run, as you are not heating up a 50 gallon tank all the time, only the water you are actually using.

Tankless heaters are not "instant" heat; if it takes 15 seconds for the water from your current heater to reach your tap, it will take just as long for the new system (unless you install a circulating pump). Once the water is hot at the tap, it will be hot as long as you have gas available.

The high BTU figure is used, because instead of heating 50 gallons of water all the time and having a tank full of hot water on hand, you are taking 56* street water and heating it to 120* in seconds. Think of it as a blowtorch as compared to a candle. It uses a lot of energy during operation, but when you are not calling for hot water, there is no energy expended.

If your current tank needs replacement, go with the tankless unit. The salesperson will need to know your usage demands; how many showers/tubs you have, washing machine(s), dishwasher(s), etc. I've seen homes with hot water spigots near the garage so the homeowner can wash the car with warm water.

Answer 2

It is going to cost a lot of money to install TWO tankless water heaters. First, the cost to purchase a tankless water heater is about double the cost of a standard water heater. There are some tax credits in place to help with the huge premium that you will pay, but you still have to have the funds to pay for the things and then wait to get the credit on your tax return. Second, the installation costs are also significantly higher for the tankless variety. Some people also have to upgrade their electrical. You'll likely want a good estimate of the installation costs before you make this decision. I know I am making a huge assumption -- that you are price sensitive. If money is no object then you may want to go with the tankless variety, although they do have some performance drawbacks if you use a lot of water. I found that plumbers recommend the tankless variety, but then they stand to earn a lot more on the installation so who knows if that is a reliable source. As the other comment mentioned, Consumer Reports does not believe that the advantages of the tankless varieties outweigh the huge costs. For more details on how to compare see the attached article.

Answer 3

Yes. Operating cost should be lower. The output of a normal water heater is about 40,000 btus. The output for a instant water heater is between 100,000 and 380,000 btus. Noritz is the best brand and carries the widest range of output. One important consideration is the temperature of the water in the winter. If you live in a very cold part of the country where the water dips below 50 degrees in the winter consider getting a water heater with more output.

The savings in a instant water heater is achieved by not constantly heating unused water. The instant water heater will typically have better combustion efficiency so less of your money will be going into the chimney. The wall mounted heater should also last longer and its life can be extended by repairs that prevent replacement.

Answer 4

An on demand hot water system is much more efficient and can literally save you ten to twenty percent on your energy costs. I have installed a Rinnai system (www.foreverhotwater.com). I am amazed at the efficiency and savings and also how fast I get hot water when I turn on the tap - it is instant, and never stops. You could take a 2 hour long hot shower. You will not be disappointed by a Rinnai. Good luck to you.