Tankless Hot Water Heaters

Steve Williams

Site Founder, Site Owner, Administrator
Having moved recently I was interested to see that our new house has a tankless hot water heater (Noritz). I have read about these devices extensively including both positive and negative comments. Some say they are efficient and some say the contrary. Some say that the investment takes years to recoup based on savings.

Suffice it to say I just received my first month's gas bill and my jaw dropped as I have never had a gas bill like this in all my years. It was a rip roaring $6.20.

For me the heater was already there so I had no major outlay. Hot water from any tap anywhere throughout the house is available in less than 10 seconds. As a result my water bill this month was also lower than I have ever had before.

Here are some interesting articles on tankless hot water heaters. Who here has one as well and please post your thoughts, pro or con


Tankless water heaters
They're efficient but not necessarily economical


Heating water accounts for up to 30 percent of the average home's energy budget. Some makers of gas-fired tankless water heaters claim their products can cut your energy costs up to half over regular storage heaters. So is it time to switch?

Probably not. Gas tankless water heaters, which use high-powered burners to quickly heat water as it runs through a heat exchanger, were 22 percent more energy efficient on average than the gas-fired storage-tank models in our tests. That translates into a savings of around $70 to $80 per year, based on 2008 national energy costs. But because they cost much more than storage water heaters, it can take up to 22 years to break even—longer than the 20-year life of many models. Moreover, our online poll of 1,200 readers revealed wide variations in installation costs, energy savings, and satisfaction.

With the help of an outside lab, we pitted Takagi and Noritz gas-fired tankless water heaters against three storage water heaters. We didn't test electric tankless heaters because many can't deliver hot water fast enough to replace a conventional water heater if ground*water is cold. Even in areas with warm groundwater, most homeowners would need to upgrade their electrical service to power a whole-house tankless model.

Our tests simulated daily use of 76 to 78 gallons of hot water. That's the equivalent of taking three showers, washing one laun*dry load, running the dishwasher once (six cycles), and turning on the faucet nine times, for a total of 19 draws. While that's considered heavy use compared with the standard Department of Energy test, we think it more accurately represents an average family's habits. We also ran more than 45,000 gallons of very hard water through a tanked model and a Rinnai tankless model to simulate about 11 years of regular use.

Here's what else we found:

Water runs hot and cold
Manufacturers of tankless water heaters are fond of touting their products' ability to provide an endless amount of hot water. But inconsistent water temperatures were a common complaint among our poll respondents. When you turn on the faucet, tankless models feed in some cold water to gauge how big a temperature rise is needed. If there's cool water lingering in your pipes, you'll receive a momentary "cold-water sandwich" between the old and new hot water. And a tankless water heater's burner might not ignite when you try to get just a trickle of hot water for, say, shaving.

Nor do tankless water heaters deliver hot water instantaneously. It takes time to heat the water to the target temperature, and just like storage water heaters, any cold water in the pipes needs to be pushed out. And tankless models' electric controls mean you'll also lose hot water during a power outage.

Up-front costs are high
The tankless water heaters we tested cost $800 to $1,150, compared with $300 to $480 for the regular storage-tank types. Tankless models need electrical outlets for their fan and electronics, upgraded gas pipes, and a new ventilation system. That can bring average installation costs to $1,200, compared with $300 for storage-tank models.

Tankless units might need more care
During our long-term testing, an indicator on the tankless model warned of scale buildup. We paid $334 for special valves and a plumber to flush out the water heater with vinegar. Many industry pros recommend that tankless models be serviced once a year by a qualified technician. Calcium buildup can decrease efficiency, restrict water flow, and damage tankless models. Experts suggest installing a water softener if your water hardness is above 11 grains per gallon. Ignoring this advice can shorten your warranty.

Efficient storage models are pricey
We also tested the $1,400 Vertex, a high-efficiency storage water heater by A.O. Smith. The manufacturer claims its installation costs are similar to a regular storage model. But its high cost offsets much of the roughly $70 per year the Vertex will save you. Instead, we recommend buying a conventional storage water heater with a 9- or 12-year warranty. In previous tests, we found that those models generally had thicker insulation, bigger burners or larger heating elements, and better corrosion-fighting metal rods called anodes.


A link showing how they work

http://www.consumerreports.org/cro/...work/tankless-water-heaters-how-they-work.htm
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
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Snohomish, WA
www.pugetsoundstudios.com
I've had mine for about 3 years now and a shower with 9 heads makes it a dream!!

I have a Rinnai
 

TheAudioAssociation

Member Sponsor
Jul 10, 2010
141
21
1,575
Anaheim Hills, CA
Have a Noritz as well. Rock solid performance and a tiny gas bill as well. Had a Bosch prior. What a POS! Water would cycle from hot and cold in the middle of a shower...... My dealer was great, took the Bosch back full credit and applied it to my Noritz.

3 years and not a problem!
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
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Snohomish, WA
www.pugetsoundstudios.com
I would love to find out how to get hot water during a power outage. All the fireplaces work with low voltage.
 

TheAudioAssociation

Member Sponsor
Jul 10, 2010
141
21
1,575
Anaheim Hills, CA
I would love to find out how to get hot water during a power outage. All the fireplaces work with low voltage.

Bruce... I use a UPS/Battery Backup with my Noritz. Since the unit only uses electricity for the ignitor I've been able to get hot water during power outages. Since our outages are short lived it's been working so far. Knock on wood!


Have you guys found that the hot water only heats when water flows at or greater than half gallon per minute. I haven't found that with my Noritz and yes it is rock solid

Steve..... haven't really measure the minimum water flow for heated water but I can tell you that my Noritz is able to generate hot water at a very low rate which my previous Bosch could not. I have the water output very low during my morning shaving ritual and it works great.
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
7,007
515
1,740
Snohomish, WA
www.pugetsoundstudios.com
Have you guys found that the hot water only heats when water flows at or greater than half gallon per minute. I haven't found that with my Noritz and yes it is rock solid

We have a direct 5/8" line going to the master and it's fine either way. At the other faucets you need to turn the hot wide open to get it to heat up quickly. It's a pretty big house though.
 

Steve Williams

Site Founder, Site Owner, Administrator
Ours is a big house as well with the master bathroom way at the other end of the house and like you I get hot water for my morning shave almost immediately. I don't have battery back up but I would say that power outages here are a rarity
 

DaveyF

Well-Known Member
Jul 31, 2010
6,129
181
458
La Jolla, Calif USA
I've been looking into switching from the typical tank to tankless. According to my plumber, who sells Noritz, Bosch and Rinnai the main factors involved are cost. Not only of the unit itself, but the additional plumbing to convert.
Plus, depending on the usage, more than one unit may be required. An example of this, my neighbor has a hot tub, multiple large showers and a long distance between the unit(s) and the bathrooms. Needs to have two units to supply correctly. VERY pricey originally to install.
I think the economics of tankless need to be looked at carefully before an install decision is made.
 

amirm

Banned
Apr 2, 2010
15,813
38
0
Seattle, WA
It has never made sense to me either. The newest approach is a heat pump as the energy source. It is much more efficient. My issue with it is that it is noisy. So you need to put it in a place where you are not bothered by it. I think the AO Smith mentioned in the article is that type.
 

LesAuber

Well-Known Member
Jun 21, 2010
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0
361
I've had a Rinnai for a few months now and love it for the endless hot water. As a migraineur I've put the feature to the test quite a few times. It's my 4th water heater in 19 years so figured it was time to try something different. The water pressure is high enough to make for great showers but seems to be murder on tanks. It's harder to judge savings dollar wise since I've got gas heat also and am on the budget plan but my gas use vs last year the same time is a rather dramatic reduction.

How to run it in a power failure is an open question. A UPS would have to be on the large side since it uses a forced draft blower. This blower is a bit noisy in the house. Since it's mounted to the wall, which acts as a sounding board, it makes a low frequency rumble. Funny part is the unit is virtually silent in the garage and no vibration you can feel with your hand on it.

The thing does seem to do fine at low flow rates though I have noticed the cold water slug when you've shut the water off for a couple minutes and then turned it back on. Warm up at the other end of the house seems to be as fast otherwise. A distance of 50 feet or so.

It will be interesting to see how well it versus the old tank heaters over the years.
 

Holli82

Well-Known Member
Jun 6, 2010
319
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Got a Noritz X 3 years. Had Tagaki before that. Noritz is much better.

Not worried about power outage. Probably won't be taking a shower if the lights are out.
 

amirm

Banned
Apr 2, 2010
15,813
38
0
Seattle, WA
Not worried about power outage. Probably won't be taking a shower if the lights are out.
We had a power failure that lasted 8 days! Perils of living in the suburbs :). Was great being able to still take showers. I tell you though, it was hard getting used to not being able to turn on the shower fan! I kept hitting the button wondering why it was not working :).
 

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