Tankless Water Heaters

[PLUMBILL]

"The Adds say they never run out of hot water no matter how much hot water you and your family uses", then in the same breth "they save energy."

How do you save more energy and $$$ if you are using all the that hot water and never run out.

[smwoodruff0908]

Well, I came across this post, and I figure I'd register to see if I could help you out a little bit. I'm an Environmental Engineer by day, so I've looked into methods of energy efficiency a couple times. I'm not, however, a plumbing expert, so I will admit my info may not be infallible, and as always, contact a professional, blah, blah, blah. I've only researched a little bit on tankless heaters, but Ill try to do my best here.

A normal tank water heater tries to keep all the water inside it at a constant temperature. This wastes energy as the heat slowly dissipates from the tank, and the heater has to consume energy to reheat it all the time. Just by having a normal tank heater in your house, and not running any water - EVER - the water heater will be using a lot of energy to reheat the water in the tank when it cools off. However, a tankless heater is an "on-demand" system, and doesn't store any water, so you're not using the extra energy to maintain hot water all the time.

Tankless systems save energy this way, and are usually more efficient at heating the water as well, so this is where you get your energy efficiency.

As far as the "suppling enough hot water for entire house." the same way in which there are different sized tank heaters for different size houses/water demand, there are also different sized tankless heaters to accommodate the different needs. So as with any water heater, you need to take your water demands into account when figuring out what the best heater would be for your specific situation.

I don't think the article meant "Hey! Run your dishwasher, laundry machine, showers, and faucets all at the same time on HOT and you'll save money!" - As with any water heater, the best thing to do is conserve the amount of water you have to heat, and you'll notice the energy/$$$ savings in the end. Hope this helps

[Sylvan Tieger]

Sorry I just saw this post better late then never I guess.

The problems with tankless heaters is two fold

1- No recirculation and 2 a heck of a waste of water

Here someone turns on a faucet and the heater kicks in as the water runs to an outlet. Then the water is shut off and the tankless heater shuts down and the water already heated is allowed to cool off until a demand for hot water is called for.

Now the water already paid for to be heated has cooled off and goes wastefully down the drain.

So your either having t pay for stand by losses for a tank or pay a larger water bill either way you lose

[oldman3000t]

The first thing everybody should know is it takes the same amout of btu to give a 80 degree rise in a tank type water heater or tankless. I would not use a tankless with kids in the house, when they have unlimited hot water they never get out of the shower. The major problem is no one installs to code or size the gas pipe correctly. It takes a lot of money to install correctly and if you live in the house for 20 years it may pay for it self.

Mike
San Diego

[Thumper]

Don't you waste the same amount of hot water if you don't have a hwr system?
I think you do save money by heating water only when you need it. But electric tankless heaters require too much amps and don't last that long. I know that gas systems are more durable than electric but more complex than water heaters.

[PLUMBILL]

I don't have a problem with point of use electric tankless used as booster heaters for long runs to fixtures, it's the whole house type with our very cold water in the winter that don't work unless you want to spend more money then you ever would with a tank type heater.