When to replace a hot water heater?

December 8, 2023 8:58 AM

I have lived in my house for 20 years and the hot water heater has never been replaced, nor serviced. When to replace one's hot water heater?

Gas hot water heater in single-family home. I don't have any hot water issues or leaking at the moment, but I'm wondering if I should replace before I have an emergency (and yes, I plan to go with tankless). The previous question about this is >10 years old, so I thought I'd ask again. I can't even see if there's leaking because it's covered in a blanket, akin to a parka per local code.
When I research online, apparently 20 years is the upper end of the life of a hot water heater, but is that just to sell more? Thanks.

posted by honey badger to Home & Garden (17 answers total)

Worth getting it serviced. See what the technician says about its condition.
posted by Klipspringer at 9:01 AM on December 8, 2023 [1 favorite]

Best answer: If you plan to upgrade to a tankless, that will be more time consuming to shop for, prepare for (do you have enough gas/electric service to power a tankless in the location of your choice?), and allow time for permitting and unit shipping, vs. a simple swap-out for whatever basic unit your plumber has on hand. It will be slower, so if you wait for an emergency/equipment failure to start replacement, you will likely be out of hot water while you wait for the new one to be delivered and installed. (Could be a day, or could be longer if it turns out you have specific model preferences)

One other consideration: have you looked at Heat Pump Water Heaters? These are highly highly efficient and are the next thing in water heaters. They use a tank so you get the resilience + water availability of a tank, but also use dramatically less energy. They also take up the space of a tank and are newer, so not everyone sells them, and they’re pricier (but there are lots of rebates/incentives, especially if you’re in California). Pros & cons.

IMHO: if you were replacing a tank for a similar tank, you can wait until your current unit fails. If you’re doing anything different than the setup of your current unit, you should proactively replace to avoid service disruption and get the unit you prefer. 20 years is a reasonable timeline.
posted by samthemander at 9:07 AM on December 8, 2023 [6 favorites]

Best answer: If that unit hasn't been flushed or checked in 20 years, I'd say it's a good time to consider it. They do corrode and wear out, even if they're cleaned. And they don't fail gradually, usually there's a leak out the bottom and the tank is done.

Getting this kind of work done on your schedule, not an emergency plumber on a Sunday morning, is also a good thing. Also look into Energy Star tax credits for a new unit, it will definitely be more energy efficient than whatever was installed in 2003.
posted by JoeZydeco at 9:08 AM on December 8, 2023 [7 favorites]

Is your water heater somewhere that can tolerate having a lot of water leaking on the floor? If so, you can let it go till it fails or service it your choice.

If water leaking everywhere from it would damage things, then look at getting it replaced before it does.
posted by TheAdamist at 9:10 AM on December 8, 2023 [5 favorites]

If you plan to replace with a more efficient unit and your current unit is not efficient (i.e. it's an old-style gas water heater where the exhaust vents out the top), then it probably makes sense to replace it now. Maybe you're losing a few years of potential service from the old water heater, but if you keep using it you're losing a lot in wasted gas because those are not efficient at all. Add in the convenience of a scheduled versus emergency replacement and I wouldn't hesitate at all to replace it.

That said, I think an electric heat pump hot water tank is a much better idea than tankless gas. A heat pump water heater is very efficient and, depending on the electricity mix in your area, potentially has much lower carbon emissions. Even if your electricity mix is currently non-renewable, electrification makes sense because your new water heater will last for roughly a couple decades and locking in a gas appliance now means you will have to keep burning gas for those two decades (or throw out the gas water heater and replace it before its time). We definitely can't keep burning gas for hot water into the 2040s!

Gas tankless also tends to waste water and energy because you have to run it for longer to get the water up to temp and doesn't work well for intermittent hot water use, like modern washing machines and dishwashers, which just pull a few litres at a time (in fact, an efficient washing machine may never get actually hot water from a tankless heater). We recently replaced our gas tankless heater with a heat pump tank and it has been a major improvement and cost savings. Gas tankless was a big thing here about 15 years ago, but most of what I've heard has been pretty negative from people who had them.
posted by ssg at 9:13 AM on December 8, 2023 [3 favorites]

Best answer: Insurance companies are also more hesitant to insure you (or cover water heater-related damage) if you have a hot water heater of that age - when we moved into our place, one of the conditions of being insured was that we replace the 20yo water heater.
posted by urbanlenny at 9:20 AM on December 8, 2023

Best answer: You posted this question on a day when our hot water heater (of unknown vintage, but likely ~20 years) died unexpectedly. So my recommendation is, get someone out to look at it now and give you a professional opinion!

As some anecdata counter to ssg's comment - the (now dead) water heater is tankless gas and is fast AF, particularly for things on the same floor - our (newer, high-efficiency) washer is in the same room and absolutely gets hot water. We do need to run it for a little bit to get hot water on the third floor (heater is in the basement), but certainly not long enough that I'm concerned about cost. Maybe it's different with more modern gas tankless? I'll know more after the plumbers get here...
posted by okayokayigive at 9:24 AM on December 8, 2023

If it fails like mine did, it will be obvious. No hot water and a giant puddle on the floor beneath the heater.
posted by A Blue Moon at 9:26 AM on December 8, 2023

I'm not sure a service call will actually be informative -- I don't know that there's much to go on in terms of when it will fail. A service person is just going to look at the manufacturing date and if it's > 10 years, tell you to do it soon.

Ours is 13 years old and I'm planning on getting it replaced this year, just to avoid an emergency call/visit. I think that's around the "standard" timeline.
posted by Dashy at 9:27 AM on December 8, 2023 [1 favorite]

Ours was over 20 years old when we bought our place, and on the top floor. We figured we could replace it for about $1200, or have it fail spectacularly and flood our entire downstairs. We decided to just replace it.
posted by jabes at 11:08 AM on December 8, 2023

I recently replaced my gas water heater before I "had" to because it was 22 years old and had some light corrosion. My plumber said "you can choose to replace it now, or you can have to replace it later". I didn't want to get caught in an emergency so I chose to go ahead and replace it and get the heater that I wanted instead of waiting for a failure and having to buy whatever is readily available. The peace of mind was more than worth it for me.
posted by mezzanayne at 11:18 AM on December 8, 2023 [1 favorite]

Best answer: Old boilers do have a reputation for longevity not matched by newer equipment, it is not that unusual to find boilers that are 40+ years old and still cranking along. The catch is that those old boilers are not energy efficient, (typically 60% vs 90%) so while you save money in not having to replace the boiler every 10 years, you are paying out significantly more in energy bills every year.
The numbers on this will vary but typically you can expect a new efficient boiler to completely pay for itself in around 6-7 years.
posted by Lanark at 11:48 AM on December 8, 2023

I replaced my this year - it started leaking out the drainage spout - it was at least 15 years old. Before that, it had started to get a bit weaker in term of how much hot water it produced but other than that, it was fine.

My quote for tankless was $4500. My replacement for a 50 gallon was $1750.
posted by The_Vegetables at 1:12 PM on December 8, 2023 [1 favorite]

and yes, I plan to go with tankless

You might know this already, but tankless hot water heaters require a lot of amps. We asked our plumber about one and they pointed out we'd need an expensive electrical upgrade to our electric panel to provide the 100 amps the tankless water heater required for our very small house. The fully electric tank water heater we had only required a 30 amp breaker.
Heat pump HW heaters are efficient and much more manageable as far as amps/upgrades required.
posted by oneirodynia at 1:22 PM on December 8, 2023 [2 favorites]

The catch is that those old boilers are not energy efficient, (typically 60% vs 90%) so while you save money in not having to replace the boiler every 10 years, you are paying out significantly more in energy bills every year.

The counter-counter argument is that depends on what your hot water usage is like. My gas bill for my (coincidentally also) 20 year old contractor grade "plumber's special" water heater is on the order of $5/month in the dead of summer when it's only being used to heat water. Even if my water heater were twice as efficient as it is now, that's what, $2.50/month? It takes a lot of $2.50 months to pay back a ~$2000 replacement.

And that's $5 with a constant gravity fed recirculator providing hot water to the second floor vanity within 2-3 seconds of opening the tap. It's amazing. Natural gas is perhaps too cheap, sure, and the utility's distribution and facilities charges both drive up the cost-per-therm, sure, but the point is that efficiency scaling is of limited impact if the cost of the current low efficiency appliance is only pennies per day anyway.

So, my take is that it sort of depends on your tolerance to cold showers, whether the tank failing would be a further catastrophe or just an unexpected way of cleaning the floor in your basement or crawl space, and if you generally have the rainy day fund to replace it as opposed to needing to save up for it. You'll pay a bit more for an emergency plumber versus a scheduled job, sure, but if you were planning on DIYing it anyway, it's not like it's going to fail via your roof. .. ... Probably.
posted by Kyol at 2:29 PM on December 8, 2023 [1 favorite]

Any plumber worth their salt will likely refuse to service a WH that old anyway and will recommend you replace it. Because as soon as you start futzing w a unit that hasn’t been touched in 20 years, it’s very likely something will fail shortly thereafter (and they’ll be on the hook for it).

If you have $ to throw at it, go ahead and do it. If not, don’t touch it!! Just start researching and saving until you can. 😂

Seconding the heat pump over tankless reccs. Tons of rebates to take advantage of, depending on where you live (I believe I remember CA, OR, WA, CT, and ME have the most) but look into it and check w your local utility company too! A lot of ppl never even take advantage of rebates bc they don’t know about them or just forget to submit the paperwork.

Bonus if you live in a warm climate: the HPWHs actually spit out cold air. So if your heater is in a hot garage/basement/attic, it’ll act like a mini air conditioner.
posted by a.steele at 5:13 PM on December 8, 2023 [1 favorite]

My father put an 80 gallon AOSmith electric water heater into the old home place in 1960, and it still works fine, so there are water heaters, and water heaters. It has had minimal service: irregular draining from the base in years of heavy use, replacement of an element, replacement of a thermostat, and has benefitted from a softened water supply
A specific consideration: do you need dehumidification at your water heater's location?
At my house I am quite happy with my GE Geospring heat pump hybrid water heater, which had the great advantage for me that it replaced the basement dehumidifier. Also, government plus utility company rebates lowered its initial cost to equal that of the cheapest conventional model, and after 10 years, it has not needed a service call. Plus I'm saving a few dollars a month.
posted by diodotos at 4:21 AM on December 12, 2023