Gas Water Heater Replacement

[HotterInTexas]

15 year old 65 gallon gas State water heater is showing corrosion on the bottom exterior of the unit. I am going to be proactive and replace it before it fails.

Background:
3 full bath house.
2 occupants.
Ranch home with a long run from water heater to master bath.
Water circulation pump (on a timer for high-demand hours) compensates for that, but I can safely assume a lot of heat escapes the pipes running through the foundation, so perhaps that's a factor I need to consider.
Efficiency (gas consumption) and having enough hot water when we need it are important. Not planning on moving any time soon.

Questions:
Do I *need* 65 gallon capacity?
Can I go smaller?
Any brands I should strongly consider, others to avoid?
Am I better off over-shooting the runway as opposed to undersizing?

This is not a cheap project and one that I want to get right...the first time.

Thanks for any advice.

HotterInTexas

[madhat]

As far as Corrosion, what you are seeing maybe nothing. It’s normal to have some rust on the outside of the tank. Condensation from a cold tank, and the moisture by product from burning gas could cause this. Look for Lime Scale tracks. Get a professional to check out the water heater, clean the burners, and pilot assembly. Check the flue pipe, all the way to the outside. Also for have them check for back drafts, with the Dryer and Exhaust fans running. That can cause rusting on the outside of the tank, and can put deadly Carbon Monoxide in your house. If you do need a water heater, I’d look for one that can heat water during a power failure. Some of the newer high efficiency ones can’t do this.

[heatingman]

If you do wind up replacing the tank, you will probably not want to go down in storage capacity, as thats what your used to.

Typically heaters and tanks are sized based on the number of fixtures. You have 3 baths plus dish machine, laundry, etc

While you may be fine with a smaller tank, that may change if say a relative stays over for a week and use increases.


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[Timmy My Boy]

My ole' man lived by the 10 year rule on replacing any hot water heater ! That’s what I do cause I’ve seen it happen a few times where they just give out ! Because 90% of people don’t do the required maintenance on them ! I’d say you’re pushing your luck at 15 years !

[Space Racer]

You can make a water heater last 20 to 30 years.

1. Check house water pressure. 80 psi is max. Regulating valves need to be replaced periodically.

2. Install a thermal expansion tank or thermal relief valve. Most residential plumbing systems are closed systems, so thermal expansion pressure needs to be relieved.

3. Install dielectric unions or other connectors to prevent copper to steel contact. Connecting copper pipe to steel tank causes a trickle current that slowly corrodes the tank.

4. Install anode rods and replace them every few years. If you do this for the life of the heater, you can get 30 years from it.

5. Keep water temperature as low as possible. The hotter you make it, the more sediment precipitates out of the water and piles up on the bottom of the tank.

6. Consider buying a State water heater. State has a patent on their dip tube, which goes in a circle around the bottom of the tank. There are also after-market dip tubes available that perform similarly, but they are not as good.

7. Consider replacing the drain valve with a full port ball valve. Most factory drain valves clog easily.


More info:
https://www.waterheaterrescue.com/Lo...how-intro.html

[BBeerme]

Don't buy your new water heater at a big box store. Had a plumber tell me they are cheaper for a reason. They look the same, but there will be one or two digits different in the model number. The big box stores make a deal with the manufacturers to cut corners so they can get a better price.

[Unlimited1]

i have seen and upgraded many to tankless units including my own home..it is strictly on demand hot water..the gas piping size is typically increased and the units are full modulating..the initial install is a bit more but you get and increased value of your home because the unit is energy efficient and hangs on the wall..very desirable!

on another home i used to have i did a 92% NTI combi unit when it first came out as i got rid of an old hydronic furnace and water heater..priority goes to the hot water via the internal heat exchanger but it also cut my gas useage in 1/2. and i now have unlimited hot water..and it hangs in the wall..

the choice is yours...

[Space Racer]

For water circulation, consider using a system that sends a trickle of water from the hot water line back to the heater through the cold water line instead of a dedicated third pipe.

For example, see https://fasterhotwater.com/WaterQuick%20Products.shtml

(I have no knowledge of the quality of this company's products.)


Also see Grundfos circulation pumps:

https://www.plumbingsupply.com/grund...fortpumps.html

https://lp.us.grundfos.com/rs/100-PJ...ort-System.pdf

Grundfos has been around for decades and has a good reputation.

[Space Racer]

BTW, State is owned by AO Smith now, so there are probably some AO Smith water heaters that have the same circular dip tubes as State.
Look for water heaters that are "Self-Cleaning."