Tankless water heater

[Ken Werner]

Thinking about replacing our older unit with one like this:

http://www.amazon.com/BOSCH-HEATERS-...8212693&sr=1-3 (http://www.amazon.com/BOSCH-HEATERS-1600P-LP-TANKLESS/dp/B000PD5LPG/ref=pd_bbs_3/103-4131515-2384662?ie=UTF8&s=hi&qid=1188212693&sr=1-3)

[bosch tankless or similar LP unit]

We have hard water, but it has a 10 yr warranty.

Anybody with experience with this type?
Does it make noise?
Our current unit is a gas fired water tank, but has a power vent with a fan that makes alot of noise as it turns on and off at night.

TIA
Ken

[Mitchell Andrus]

I looked into these a while ago and spoke to a few plumbers. They ALL said not to waste my money on a cheap one. The controlers, valves, sensors etc., are all critical to the proper operation. They rip out the cheap ones when the homeowner passes $300.00 in service calls... 5 to 7 years old. Warrantees usually cover parts only after a few years.

Soooooo, the expensive ones will never pay for themselves in fuel savings, they don't last long enuogh to recapture their costs. If space is a factor, you'll pay for the saved footage.

The one you've posted is minimal for a family. $550.00 3 gpm, 60 degree rise won't run a shower for very long unless you've got a water saver at the nozzle. Also, about a gallon has to run through any of these types to trip the heater on. No big deal if you're filling a washer, a PITA if you just want to wash your hands, or take really short showers. Many people add a 6 gallon tank-type heater after the tankless to fill in the gap and get instant hot water.

The bigger ones deliver 4.5 to 6.5 gpm, but cost $750.00 to $1,000.00. By comparison a 30 gal tank heater costs about $275.00 and will last 20+ years. You can buy several! Including the cost to keep a 6 gallon unit hot, I calculated my energy savings at about $8.00/month if I were to install a tankless. Not worth it for me.

[Stephen Beckham]

Ken,

My wife and I also considered this option. But the other factor we looked at was four kids... There's not much rest time for the Hot Water tank right now - so it's not heating water to just sit very long. It keeps up with the usage and not a lot of waste between cycles (to our uneducated guessing).

We have delayed the possiblity until this one goes out. Hopefully by then, the three oldest teenagers will be gone (not that I want them out that bad) and then there will be lots of dwell time between showers. Then the instant hot-water might make a difference.

One other note - be careful with salesmen. Although it might be a correct statement, the gentlemen we talked to suggest several units. A couple of the "under-the-sink" mounts in the bathrooms and/or kitchen and then the big one for the showers. One of the reasons stated was that individual units will be more effective for their intended use and less secondary effects from someone washing their hands while you're in the shower.

[Jim Becker]

We are putting tankless in our addition to service the master and guest baths. It will also cover the new laundry, but we don't really use much hot water there. There is no space for a tank type HWH and it's totaly impractical to even think about using the existing system due to distance. A large capacity, higher end tankless is therefore our choice.

[Al Willits]

Right off the bosch site

"""""

The AquaStar Water Valve Assembly requires periodic
maintenance. Some of the components need to be
replaced every two (2) to five (5) years. Exactly how
often depends on water conditions and use. Failure
to maintain this assembly could result in unsafe
operation of the gas valve and costly damage to the
rest of the heater.
""""""""""
When your considering costs, be sure to include this, usually requires a plumber as water lines need to be broken (depending on codes) and plumber are not cheap.
Hard water, figure every 2 years.
Parts and labor, usually not covered by warrt.

This will be applicable to most instantaneous water heaters.

These units are not as cheap to run as the sales procures make out.
Also make sure the temp rise will be sufficent for your needs, the inlet water temp will make a big difference, especially if you live in the northern states.

Be careful.

Al

[Dennis Peacock]

I checked into this for our family. Another thing to consider is how much of a rise in water temp you'll have to achieve to get the desired water temp and how much water will be "on demand". In the winter months, we would have had to have 2 tankless systems "daisy chained" to get the water temp to about 140º F with the primary system doing most of the raising and the 2nd one bring the water temp up to the final 140º F.

We opted to stay with a standard water heater. :)

[Greg Peterson]

I installed a Takagi unit this spring. No looking back.

There is up to a $300 tax credit on tankless water heaters available from the feds through the end of this year. That definitely helps.

A few comments raise a brow a time or two for me.

On demand is not the same as Instant. On demand simply means the water heater turns on when there is a demand. Most units activate at a pretty low volume threshold. It can take a few seconds to get hot water, but it is a minor difference.

Water hotter than 125 degree's can scald you so I'm not sure what is the need for 140 degree water. Perhaps a dishwasher?

Water heaters sit for a great portion of the time. Even with high demand, there are many hours throughout the day/evening/night when it is simply keeping a specific volume of hot water available.

$8/month savings over 20 years is $1,920 dollars. A 30 gallon tank will deliver twenty gallons of hot water, which is about a ten minute shower. Once the hot water starts running, the burner or heating element starts running, and continues long after the demand ceases.

Tankless may not be to everyones liking, but for me it made the most sense. I was able to do the installation myself and with the tax credit it turned out to be the same cost as a new 40 gallon unit.

Saved space and reduced utility bill, and I never run out of hot water! Big plus if you have teenagers around.

[Greg Cole]

Hey Jim,
I assume HWH - hot water heater? If it's already hot, whatcha need to heat it again for? :D
Same reason LOML "unthaws" something when she takes it out of the freezer?:p

Cheers.

Greg

[Ed Garrett]

I bought a Rinnai tankless water heater 4.5 years ago. I researched the heck out of it for a year. Great product, great results, it's quiet, efficient, etc. For me it was worth the cost because the space saved allowed me to install a utility sink in my laundry room.

But saving money wasn't part of the equation. About the time I got it natural gas prices shot up. Worse than that: my two teenagers have taken hour-long showers for the last 4.5 years. In this regard, not running out of hot water is a disadvantage.

P.S.: My favorite feature is the remote control system. When you take a shower you just can punch in the temperature you want and then just hop in the shower and crank the hot valve. No adjusting cold water into the mix. No temperature surges.

Sincerely,
Ed Garrett
Tallahassee

[Randy Denby]

I bought a Rinnai tankless water heater 4.5 years ago. I researched the heck out of it for a year. Great product, great results, it's quiet, efficient, etc. For me it was worth the cost because the space saved allowed me to install a utility sink in my laundry room.

But saving money wasn't part of the equation. About the time I got it natural gas prices shot up. Worse than that: my two teenagers have taken hour-long showers for the last 4.5 years. In this regard, not running out of hot water is a disadvantage.

P.S.: My favorite feature is the remote control system. When you take a shower you just can punch in the temperature you want and then just hop in the shower and crank the hot valve. No adjusting cold water into the mix. No temperature surges.

Sincerely,
Ed Garrett
Tallahassee

I think I would take advantage of that remote control feature and adjust the temp to 50 degrees after my teen was in the shower more than 15 minutes.:D

[Ed Garrett]

I think I would take advantage of that remote control feature and adjust the temp to 50 degrees after my teen was in the shower more than 15 minutes.:D

Randy,

That's a fine idea, but I have found (at least in my house) that the teenagers somehow end up winning these battles...

Sincerely,
Ed Garrettt
Tallahassee

[Stephen Beckham]

Ed - the water temp thing was another benefit. It seems funny to warm water to the point that it burns the skin only to cool it back down by mixing cold water back in with it - must have been the power and gas guys that came up with that plan.

All this talk is making me re-consider the swap now versus waiting till the kids are out...

[Ken Werner]

How about if you keep that remote a secret?

Nah, Ben would outsmart me one way or another.

Ken

[Mitchell Andrus]

Stephen,

Delivering water at the tap at 150 degrees (for the sake of easier math) allows you to stretch the availablity of water in the shower at 100 degrees. Mixing in cold doesn't make the hot water less hot. It makes more water at 100 degrees and allows the delivery of water at 150. (Not that you'd want to, but the illustration carries through)

If you set the controls to deliver 100 degrees at 3 gal/minute... that's it. Deliver hot at 150 and stretch it with a mix of cold, you've effectively made 100 degree water at 4.5 gal/minute. The hot water wasn't wasted, it's still there and a shorter shower heats only the water you use in each case.

[Ed Garrett]

As I remember the specs on the Rinnai unit I bought, it doesn't mix in cold water to deliver the selected temperature. Instead it has a computer which considers the input and output temperatures and adjusts the gas and input water valves accordingly. If for example somebody starts a 2nd shower, the flames inside the unit get turned up, and if necessary it will close down the water intake valve and reduce the delivered water rate in order to maintain the selected temperature. That's why even if somebody flushes a toilet or cranks another full blast shower, the delivered temperature stays constant.

Sincerely,
Ed Garrett
Tallahassee

[Pat Germain]

I saw the plumber on Ask This Old House install a tankless water heater a few weeks ago. It was vented to the outside straight through the wall behind the unit.

Is this required for all tankless water heaters, or can they be vented "up"? I was considering installing a tankless when my cheap, contractor heater goes belly-up. Being in the basement, I wouldn't have an outside wall to vent through.

[Greg Peterson]

Pat, you can vent up but there are parameters (length, number of elbows....). Also, tankless water heaters use stainless steel venting, which isn't inexpensive. The shortest, most direct venting is the best solution.

[Stephen Beckham]

Sorry Ed - that was a poor attempt at humor on my part. I was talking about the conventional way of heating water. Make it real hot and then mixing with cold water at the faucet.

The humor was that electric and gas HWH providers giggle everytime we turn up the cold water to reverse the effect we just paid for.:o

[Al Willits]

Be aware some units are fixed inputs and throttle water flow to keep desired temps and some increase input of the burner, makes a big difference.

Also in northern climates, a standing water heater even with a good grade of insulation will lose some of its heat to the surrounding room, 6 months of the year its not a loss as temps are cool enough to warrant heating the house.
Doesn't work that way in southern states though, but something to consider.

Big thing is to check all the variables when deciding on a water heater, then find the one that works for you.

Al

[Greg Peterson]

"Big thing is to check all the variables when deciding on a water heater, then find the one that works for you."

+1