Tankless Water Heater - does it waste water?

Desert Captain wrote:

kedanie wrote:
We have a Precision Temp tankless in our coach. It works just fine supplying an endless supply of hot water. The water in the lines between the faucet and water heater need to be heated up just the same as a tank style unit, the wasted water is the same.

Those that have never had one routinely mock the tankless units and those who have them love them. A never ending battle based on misinformation. From experience, ours uses less propane than the tank style as it doesn't have to store a tank of hot water. It only has to heat what is currently in demand.

The war of words and ignorant fear mongering will never end!

Keith

Just a tad "selective" with your facts... :S

The tankless crowd, both sellers and buyers, tout the "endless supply" off hot water which is utter nonsense. The only time that works is if you have full hook ups and don't give a rats bladder about wasting water. That endless supply will fill your grey tank very quickly and the tankless water heaters burn significant amounts of propane. Without full hookups a tankless water heater is close to worthless.

The conventional AC/LP tanks are well insulated and run very little. When you have AC power at your site they cost you virtually nothing for all of the hot water you will ever need. On LP they quickly heat 6 gallons {and keep it hot}, in mere minutes.

Tankless water heaters in an RV are a solution for which there was never any known problem. :R

As always.... Opinions and YMMV

:C

Our Greyhawk came with the second generation Girard tankless water heater. It was not a good fit except for those rare occasions we were on full hookups. Then it became balky and frequently refused to ignite on-demand. We had Jayco authorize our dealer to replace it with a Suburban tank model under warranty, and we've been much happier.

S Davis wrote:

kedanie wrote:

S Davis wrote:
They will waste more water, unless they have a constant recirculation or heat setting. This setting keeps the heater warm and reduces the amount of time for the heater to start heating the water. Kind of defeats the purpose of the unit. All the tankless heaters take time to sense the water flow, start the ignition cycle and then get the heat exchanger up to temp. could be anywhere from 5 seconds to 20 seconds.

So what is your experience with these units?


Ours fires up in less than 2 seconds with as little flow of .5 gallons per minute.

Our real life propane use is less than with a tank type unit Ike we used to have.

The only advantage tank types have is that they have the ability to run on electricity. With more and more rv parks charging a meter rate for the electricity used, the electric option is a waste compared to the cost of propane.

How much water do you waste when you have to empty the water heater tank after a camping trip?

Check out the real facts for the Precision Temp RV500 on line. Yes, it really does use less propane!

Learn the facts before spreading rumors and non-truths.

Keith

Almost 30 years in the plumbing and heating trades specializing in boilers and hydronics so I guess not much. I have probably installed over a thousand tankless heaters of all different brands, and I do have one in my house as well. But you must know it all since you have one in your RV.

Agreed both of your post have been spot on. Nothing wrong with tankless but without recirculation of some sort they do waste a more water than a conventional heater. Maybe a deal breaker for some and not a big deal for others. but the waste occurs either way
I am also in the plumbing business and have yet to see a tankless produce instantaneous hot water without delay.

kedanie wrote:

S Davis wrote:
They will waste more water, unless they have a constant recirculation or heat setting. This setting keeps the heater warm and reduces the amount of time for the heater to start heating the water. Kind of defeats the purpose of the unit. All the tankless heaters take time to sense the water flow, start the ignition cycle and then get the heat exchanger up to temp. could be anywhere from 5 seconds to 20 seconds.

So what is your experience with these units?


Ours fires up in less than 2 seconds with as little flow of .5 gallons per minute.

Our real life propane use is less than with a tank type unit Ike we used to have.

The only advantage tank types have is that they have the ability to run on electricity. With more and more rv parks charging a meter rate for the electricity used, the electric option is a waste compared to the cost of propane.

How much water do you waste when you have to empty the water heater tank after a camping trip?

Check out the real facts for the Precision Temp RV500 on line. Yes, it really does use less propane!

Learn the facts before spreading rumors and non-truths.

Keith

Almost 30 years in the plumbing and heating trades specializing in boilers and hydronics so I guess not much. I have probably installed over a thousand tankless heaters of all different brands, and I do have one in my house as well. But you must know it all since you have one in your RV. And I think it is you that needs to "Learn the facts before spreading rumors and non-truths."
Here is a quote right out of the manual for your Precision Temp RV500


"It is recommended that even when dry camping, take a real shower and leave the water running
as you would at home. You won't run out of hot water and you won't have to waste water waiting for the cold water to purge from the water line every time the water is turned
back on. RV showerheads are designed to drip when turned off and will allow the hot water
line to be filled with cold water."

But you will run your tanks dry quicker and waste some water on start up.

S Davis wrote:
They will waste more water, unless they have a constant recirculation or heat setting. This setting keeps the heater warm and reduces the amount of time for the heater to start heating the water. Kind of defeats the purpose of the unit. All the tankless heaters take time to sense the water flow, start the ignition cycle and then get the heat exchanger up to temp. could be anywhere from 5 seconds to 20 seconds.

So what is your experience with these units?

Ours fires up in less than 2 seconds with as little flow of .5 gallons per minute.

Our real life propane use is less than with a tank type unit Ike we used to have.

The only advantage tank types have is that they have the ability to run on electricity. With more and more rv parks charging a meter rate for the electricity used, the electric option is a waste compared to the cost of propane.

How much water do you waste when you have to empty the water heater tank after a camping trip?

Check out the real facts for the Precision Temp RV500 on line. Yes, it really does use less propane!

Learn the facts before spreading rumors and non-truths.

Keith

They will waste more water, unless they have a constant recirculation or heat setting. This setting keeps the heater warm and reduces the amount of time for the heater to start heating the water. Kind of defeats the purpose of the unit. All the tankless heaters take time to sense the water flow, start the ignition cycle and then get the heat exchanger up to temp. could be anywhere from 5 seconds to 20 seconds.

The question asked was does the tankless waste water.
From our experience using both types of water heaters is that the tankless doesn't waste any more water than a tank style. Both styles have to move hot water from the heater to the faucet being used. The only difference is the tankless doesn't start heating until you open the faucet. It then heats the water almost instantly.
As to propane use, both types use a bunch of propane while running. The tankless only uses propane when there is a demand for hot water. The tank style must heat up the water in the tank. You can hear them running and sound like a jet engine around the campgrounds in the morning. The Precision Temp unit we have uses less propane than the Atwood tank unt we used to have. That is a fact! Sure, it doesn't have an electric side, but when boonedocking neither does the tank unit.
As I said earlier, those who don't have one will mock them and run them down basing their information on what their friends brother-in-law's coursing heard from Joe Blow. Those that have them mostly like them.

The bottom line is that they all wast the same amount of water!

Keith

It does sound like RV 6 or 10 gallon tanks are essentially tankless heaters with a buffer, so there is little difference :).

In my S&B, the tankless heater has been awesome for 11 years. Instant hot water, no waiting and super cheap to run.

The purchase cost was the same as a traditional tank heater, becsuse I shopped around for a good deal.

Tankless is a good idea at home. Because there is an energy rebate and there are no waste tanks to consider? However in an RV there is no energy savings and the waste factor is more of an issue. My 10 gallon heater never runs out of hot water, essentially I have an unlimited supply under normal conditions.
If I have hook ups/sewer to take care of excess waste water than I have electric to heat the water for the cost of admission.... I just don't get it.
Why would i want tankless in an RV. By the way I do have a tankless at home.

kedanie wrote:
We have a Precision Temp tankless in our coach. It works just fine supplying an endless supply of hot water. The water in the lines between the faucet and water heater need to be heated up just the same as a tank style unit, the wasted water is the same.

Those that have never had one routinely mock the tankless units and those who have them love them. A never ending battle based on misinformation. From experience, ours uses less propane than the tank style as it doesn't have to store a tank of hot water. It only has to heat what is currently in demand.

The war of words and ignorant fear mongering will never end!

Keith

Just a tad "selective" with your facts... :S

The tankless crowd, both sellers and buyers, tout the "endless supply" off hot water which is utter nonsense. The only time that works is if you have full hook ups and don't give a rats bladder about wasting water. That endless supply will fill your grey tank very quickly and the tankless water heaters burn significant amounts of propane. Without full hookups a tankless water heater is close to worthless.

The conventional AC/LP tanks are well insulated and run very little. When you have AC power at your site they cost you virtually nothing for all of the hot water you will ever need. On LP they quickly heat 6 gallons {and keep it hot}, in mere minutes.

Tankless water heaters in an RV are a solution for which there was never any known problem. :R

As always.... Opinions and YMMV

:C

mlts22 wrote:
I have seen a tankless water system that does pretty well. Truma makes a water heater that recirculates, so water that isn't used goes back into the fresh water tank. I wish Girard would do this, as two gallons is a lot of water when boondocking.

I have the Truma HW heater and love it. Several comments:

1. My Truma does not have a recirculating pump. I do not believe the Truma has a recirc system.

2. The "wasted" water is the amount of water in the pipes between the Truma and the device...shower, vanity or kitchen sink. HW, once it clears the line, is constant without fluctuation.

3. You need to temper the HW with the cold water. Depending on the incoming cold water will determine how much HW needs to be throttled.

Truma sent me some certificates for $50 debit cards when you register a new Truma HW heater. If interested, send me a note and I'll send you a copy.