Gas water heater recommendations


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Old 04-01-24, 06:35 AM
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Gas water heater recommendations

I think it's time to replace my two gas hot water heaters as it seems like we've seen more rusty water recently (it will run clean after awhile, but given the age we'd rather replace before we get a leak). I didn't install them but from what I can tell it looks like they are both over 20 years old. They are running in sequence, and we have never had a problem of running out of hot water. It looks like they are:
1. Maytag, 50 gallon 65k BTU
2. Rheem, 50 gallon 60k BTU

A quick google shows me it's more common now to have 36k to 40k BTU water heaters. I'm guessing things are more efficient now than 20+ years ago, but I wanted to make sure I wouldn't be disappointed with the output.

Also it looks like 50 gallon hot water heaters run about $1k. By my estimate with labor it shouldn't be more than $3k to have a plumber install them. Does that sound right, or am I way off?

Thanks for any advice.
 
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Old 04-01-24, 05:34 PM
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A smaller burner doesn't necessarily mean higher efficiency.
It does mean they'll take longer to recover.

The newer water heaters are direct vent.... thru the wall... no chimney.
 
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Old 04-02-24, 09:39 AM
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Thanks. I had various opinions from plumbers on if i should leave the 2 hot water heaters in sequence, or put them in parallel. Is there a right answer?
 
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Old 04-02-24, 10:22 AM
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Not a plumber but thinking about how it might work...

In series, the first (closest to street with incoming water temp of 40-50 deg F) will heat the water and feed that hot/warmer water to the second unit. During operation, the second unit will be fed by warmer water than the first unit (incoming temp of 120 deg F to the second unit) so little additional heating would be added. This would have the first unit doing significantly more heating than the second unit. During idle time, the water in both tanks will be hot and you would have the capacity of both units. Once you drain that down, during usage periods, it could recover faster than having one unit or two in parallel since the water is warmed in the first unit then heated again in the second. this might suggest using different specification for the two units: maybe a smaller high recovery unit closer to the street and a larger capacity but cheaper (slower recovery) for the second unit.

In parallel, both tanks receive the same temp water from the street so both expend the same amount of energy to heat the water. The capacity is truly the full capacity of both tanks but recovery time is the same as having one tank.

Not sure if this helps your decision since I don't really know your usage pattern. I am sure others will confirm or correct my assumptions.

- Peter
 
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Old 04-02-24, 11:32 AM
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\When installed parallel it is possible that more water is used from one tank than the other. The water flow will follow the path of least resistance so the tank with the best water flow will get the most use. The closer you can keep the hook-up for both tanks identical to balance the flow the better it will work.

Describe your home and it's hot water use. Are the water heaters providing water for heating the home? How many people live in the home? Most homes do fine on just one heater so you might be able to go without the second heater.
 
 

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