Tank Water Heater vs. Tankless Water Heater

impliedconsentNovember 15, 2010

Recently, while doing my "bi-decade" home inspection of all parts big and small of the house, I ran across our 17yr old hot water tank (A.O. Smith 40/G NG). There seemed to be some weird funkiness to the tank and it got me to think that I should replace it. After doing some research, I found that maybe I should have replaced that thing about 7yrs ago (which partially explains my cold showers ... the other part belongs to my wife ... anyway).

So, more research. I didn't find any tank water heaters that qualified for the 30% Energy Star initiative (best I found was .70EF). What I did find, which surprised me, were plenty of tankless that did qualify for the credit. More research...and narrowed it down to a brand called Navien and model NR-210A.

So, calling my local plumber(s), I wanted job quotes for: 1) install / replace tank water heater with one of the .70EF models ... and ... 2) install / replace to Tankless Navien. Here's where it gets ugly.

1) house was built in 1993, fist owner. Since it was built in 1993, the codes were different. For me to install a new tank HWH would require the company to install a square cement wall around the unit and deepen the ditch (it's in a "half" crawl space with 6' height). The existing unit is 48" and newer units are taller. BLUF: to replace with a .7EF HWH, 12yr warranty, do the install with construction will cost me about 3k and no 30% Fed Credit.

I've had 3 companies come out and they won't touch it without the modifications. My 3k quote was the low quote (I won't even suggest what the others were). From all the research I did, the Nevien consistently hit the top of the charts as it relates to EF and warranty (my 2 criteria). I provided each company with my research. I got responses from my research: from dumbfounded - never heard of companies like Navian or Noritz or Paloma ... to stunned happy surprise that a consumer did research. My research was done not on company market fluff, but the governments Energy Star program. As of right now, there are ZERO tank HWH's that qualify for the credit.

2) for 3.3k, I get a new Navien NR-210A (bells/whistles), .98EF and installation of circulation T's at the long runs on external circulation, 15/5yrs warranty ... and the 30% Fed Credit. To me it was no brainer. More efficiency, less cost overall after credit.

My math:

Standard tank: 3000.00

Tax Credit: 0.00

TOTAL: 3000.00

Tankless: 3300.00

Fed Tax Credit: 990.00

State Rebate: 199.00

TOTAL: 2111.00

Delta: 889.00 savings going tankless, + reduced gas costs.

Thank you for reporting this comment. Undo

"Standard tank: 3000.00 "

That is an outrageously expensive water heater.

Did they gold plat the inside of the tank for corrosion protection?

    Bookmark   November 20, 2010 at 7:32PM
Thank you for reporting this comment. Undo

If it didn't include delivery and 2 years of free gas, tell'm to take a hike.

    Bookmark   November 20, 2010 at 9:56PM
Thank you for reporting this comment. Undo

Most of the cost was not the tank, but the construction they would have to do to get it to code. I'm not clear on exactly what the spec's of the code are; however, it involved creating a 4" minimum width, 4sided-concrete wall. They said because of the height of the 6' crawl space, they would have to dig a ditch deeper (certain spec) to comply with vent angles, etc...

I'm not a plumber, but 3 separate companies wouldn't touch a normal tank install without doing the modifications. Tankless: mount, hook-up, done. (I have a 1" gas main into the house, made it easier).

    Bookmark   November 22, 2010 at 6:25PM
Thank you for reporting this comment. Undo

Guys if you read the post, the reason the tank water heater was so expensive was due to the construction required to get his house up to code. I personally like my tank heater.

If your changing from a tank to tankless there is alot of work to do. Moving water lines, moving gas lines (possibly upgrading gas line size too) and running a new intake/exhaust if using gas, upgrading the main service amps if using electric.

Some things to consider

Tank Heater


  1. Costs less to replace in the future
  2. Easier to maintain (Tank water heaters are easy to flush out every year)
  3. Easier to install (dont have to upgrade gas line or main service amps)
  4. Gas water heater will still operate in power outage (electric will still have some hot water to use for a while till power kicks back on).


  1. Not as efficient as tankless
  2. No Tax Credits
  3. Hot water limited by FHR (first hour rating)

Tankless Heater


  1. Unlimited hot water
  2. More efficient
  3. Saves space


  1. Will cost more in the future to replace (there is no guarantee the tankless will last longer than a tank version, the heat exchanger can go bad and that is the most expensive part of the tankless) ,
  2. Harder to maintain (you need to try to clean those tankless heaters out every year with a descaler so they stay working efficiently)
  3. Harder to install (upgrade gas line or main service amps)
  4. Tankless heaters have a limited throughoutput. While it is unlimited hot water, it can only supply so many gallons of hot water at a time
  5. Will not operate in a power outage. A tankless water heater is controlled by electronics whether the heater is gas or electric does not matter.
  6. Requires minimum gallons per minute from city water supply, some people have not been able to install due to that problem.
  7. Consumer reports note that users complain of inconsistant water temperatures. http://www.consumerreports.org/cro/appliances/heating-cooling-and-air/water-heaters/tankless-water-heaters/overview/tankless-water-heaters-ov.htm

Another good site to look at: http://www.waterheaterrescue.com/pages/WHRpages/English/Longevity/tankless-water-heaters.html

    Bookmark   February 12, 2015 at 8:06AM
Sign Up to comment
More Discussions
softener is not using up salt
I have hard well water (35 gpg, 0.5ppm iron, pH 7.0,...
Help with smelly well water
Just a little background. We bought a house 3 years...
what brand water softener
have 2400 sq ft rancher on town water. do not have...
how to turn off dual water handle on kitchen valves
I need to turn off water to kitchen sink. We have...
Marble shower panels valve replacement :( !!!
We have a couple of bathrooms with a single handle...
Vamsi Kodavanty
Sponsored Products
Bleeker Street Oil Rubbed Bronze Three-Light Bath Fixture
$192.60 | Bellacor
Smart Box Humidifier - White
| Dot & Bo
Tuscan Villa Four-Light Bath Fixture
$242.10 | Bellacor
Maison Tall Pillar Candle Holder
$69.50 | FRONTGATE
Dual Exposed Thermostatic Shower Faucet, Rigid Riser Kit & Round Head
Hudson Reed
Exaco 95 Gallon Roman Rain Barrel with Planter - 211602
$699.99 | Hayneedle
Virtu USA MS-55-FG-ES 55 Vincente Single Sink Bathroom Vanity in Espresso
$899.00 | Blue Bath
Thermostatic Shower Tower Panel Column System
Hudson Reed
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™