Tankless water heaters

[Harry Everhart]

In article ,

Bosch - Takagi - Rennai all make great tankless gas water heaters. Rennai seems to be the top of the line.

[Edwin Pawlowski]

IMO, Paul Harvey is a rather credible individuals and I'd not hesitate to buy anything he is selling. I'd rate him as one of the most interesting people in the world. Honest.

[Richard J Kinch]

This defies elementary thermodynamics. A smaller heat exchanger with less time of contact cannot possibly be more efficent.

[Harry Everhart]

I am not that smart either. Here are some charts from the Department of Energy -

[Chris Lewis]

In raising X amount of water Y degrees. Yes.

But that's not all there is. What about all the energy you waste when extra hot water you've had to run for 60 seconds to get _any_ warm water to the tap, sits in the pipes overnight? With tankless, that's not an issue.

Efficiency, to mean anything, has to include the whole system. Including heat loss off the pipes.

[Richard J Kinch]

That's a point-of-use issue. Nothing to do with tankless.

[Richard J Kinch]

That's a boob-bait Web site with stupid claims, not a government source (not that Jimmy Carter's DOE would necessarily be sensible).

[m Ransley]

Not only no standby loss but no pilot loss and no thermal loss on pipe to tank. My small Bosch is 2 D cell battery ignition, no pilot. Effecienceis of tankless are 81 - 94%, 94% for the new Takaki. Tanks calcify on the bottom with scale. I recently removed a tank in my apt building on relativly soft water. There was 14" of scale in the tank, now that kills efficiency. Tankless dont loose efficiency as tanks do. There are many sites showing individual units efficiencies. Overall going from electric tank to Ng tankless my bills are down 75%.

[nicksanspam]

I have the impression that lots of tankless heaters keep a small part of themselves warm all the time.

That wouldn't change the efficiency of an electric heater.

They never scale?

Nick

[Harry Everhart]

Dear Rich - No matter what we say - you are not going to be impressed. That fellow told you he saves 75% on his tankless gas water heater - but your mind is made up. We don't want to argue with you - if you don't agree - don't buy one. But we have studied this to the point of purchasing them. My neighbor put two in just a few months ago - and loves them. You seem to just want to argue. I do not like evangelists that try to convince folks to do something pro or con - especially when they have nothing but a cranky opinion - but no data to back it up. On top of all that - my city likes them so much - they are willing to give me $900 in rebates just to install them. As much as I value your opinion - please present information showing that tankless heaters aren't as good as tank types. I am willing to listen to other information - my mind is not closed - but it must be more than someone just arguing for argument's sake. Thanks for caring about us so much to try to convince us not to make a mistake. Harry

[m Ransley]

If you get one with a standing pilot sure there is the pilot loss. That is the Bosch 80-81 % units . From pilotless efficiency goes from 82% up to 94% depending on unit and manufacturer. Harry E., Rich Kinch has been all over trying to put them down and calling companies like Bosch fly by night. Bosch should anyone care to look at a company report is like our GE or GM , big and established. Kinch probably can`t afford one so this is his justification and cuts them down baselisly

[Richard J Kinch]

As regards efficiency, I did: simple thermodynamics, time, and space. Heat exchangers become *less* efficent as they get smaller and faster, not more.

I am not an "evangelist". I am a skeptical engineer, with reasons to be skeptical. The burden of proof is on you if you claim the old ways are obsolete.

Look at the hucksters and swindlers that sell these things.

Look at the testimonials instead of metered testing.

Look at the performance claims that defy elementary BTU calculations.

Look at the absurd claims about how bad conventional units are.

Wrong. I am impressed by facts and analysis. Not testimonials that defy freshman physics.

This is exactly the response of those who won't accept the truth when the truth doesn't fit their candyland ideas. This is the response of advocates of perpetual motion machines, 100 mpg automobiles, 50000X Rife microscopes, lifetime paint, magnetic water softeners, septic digesters, $1200 boom boxes, bagless vacuum cleaners, waterless cookers, light bulbs that don't burn out, plates that don't break, stuff to pour in your gas tank to fix your engine, knives that never need sharpening, glue that sticks to everything, and the fountain of youth.

Show me some engineering analysis and testing. Guys with meters and thermometers who aren't trying to sell something. Not sales brochures, not testimonials, not reports from across the ocean in another alphabet and language. Loan *me* and unit and let me run it through my laboratory.

Show me somebody in the USA who makes these things that I can sue when their claims of 75 percent savings is proven to be the bunk that it is.

[m Ransley]

Kinch the Grinch you are a true moron

[m Ransley]

Hey Kinch the Grinch you Stupid Shit, did you know you can get a 96.7% efficient furnace. Did you know you can get a 97% efficient WH tank, go back in your cave kinchy.

[Jim B]

Izit a gas or electrical unit. Also, which is more economical electrical or City gas?

Thank

[Andy Hill]

Ours is a natural gas unit. I'm not familiar with the manufacturers of the electric tankless heaters (which, AFAIK, are all different from the guys who make the gas units). I doubt there are very places in the US where it's cheaper to run electric rather than gas (I live in an area with under 6 cents a kWh power, and it's still cheaper to use gas for heating anything).

[Richard J Kinch]

That's code language for "these things are a bad idea all around", which is what I've been saying here for years. A retailer like Home Depot has to more or less deliver what they promise, and they can't make a business out of selling fantasies like tankless water heaters.

We hit the swindlers' trifecta today in the Palm Beach Post newspaper: ads for tankless water heaters, never-paint-again liquid siding, and dust mite duct cleaning.

[Edward Grant]

I stopped at Home Depot yesterday and asked about a tankless water heater. The salesman told me that they don't carry them because they are undependable and the parts are very expensive. That was the first time I had heard that. How about anyone else?

[George]

They may not be able to carry the good brand (can't buy them at their price, supplier decided homeowners who install them won't do it properly etc) so they are badmouthing them.

[Andy Hill]

Well, it's not like he's going to say they were the greatest thing since sliced bread, but they weren't selling enough to make it worth their while...

I like mine, but they're certainly not for everyone. I'll let you know in another 25 years or so about the reliability aspect...