Worth changing 40 gal. to 30gal. hot water tank?

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dodgy55
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Worth changing 40 gal. to 30gal. hot water tank?

Post by dodgy55 » Thu Nov 09, 2017 9:45 am

Had our home for about 10 years now and I was thinking maybe this is the time to think about installing a new hot water tank. I am guessing the tank is around 12 years old. Water is heated by natural gas. Since it is just myself, wife, clothes washer, and dish washer I was considering swapping to a 30 gallon tank. Not sure if the savings would justify the occasional lack of sufficient hot water. Has anyone had experience changing to a 30 gallon tank and found it worth the effort?
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sunny_socal
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by sunny_socal » Thu Nov 09, 2017 9:51 am

Why on earth would you downsize? We went a size bigger last time we replaced ours!

It's a great emergency drinking water supply as well :happy
Last edited by sunny_socal on Thu Nov 09, 2017 9:52 am, edited 1 time in total.

WhyNotUs
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by WhyNotUs » Thu Nov 09, 2017 9:52 am

Do you mean worth it in terms of dollars saved from energy cost?
From an energy perspective, the difference between a 12 year old tank and a new tank is probably greater than the difference between 30 and 40. You could also buy a 40 gal that uses less energy than a 30 gallon. Each one has a label on it with expected annual energy cost for comparison.

A tankless system would give you energy savings, space savings, and more hot water but it not well suited for every application.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Point » Thu Nov 09, 2017 10:03 am

Insulate the tank with a good water heater blanket and don’t sweat it

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Grt2bOutdoors » Thu Nov 09, 2017 10:03 am

WhyNotUs wrote:
Thu Nov 09, 2017 9:52 am
Do you mean worth it in terms of dollars saved from energy cost?
From an energy perspective, the difference between a 12 year old tank and a new tank is probably greater than the difference between 30 and 40. You could also buy a 40 gal that uses less energy than a 30 gallon. Each one has a label on it with expected annual energy cost for comparison.

A tankless system would give you energy savings, space savings, and more hot water but it not well suited for every application.
Not to hijack thread, but am also thinking of replacing my now 10 year old tank. How does one compare a tankless system with the output of a 40 gallon unit? I also use natural gas.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by dbr » Thu Nov 09, 2017 10:08 am

dodgy55 wrote:
Thu Nov 09, 2017 9:45 am
Had our home for about 10 years now and I was thinking maybe this is the time to think about installing a new hot water tank. I am guessing the tank is around 12 years old. Water is heated by natural gas. Since it is just myself, wife, clothes washer, and dish washer I was considering swapping to a 30 gallon tank. Not sure if the savings would justify the occasional lack of sufficient hot water. Has anyone had experience changing to a 30 gallon tank and found it worth the effort?
Experience going the other way, actually to 50 gal. Your choice would seem odd to me. Do you ever have guests in the house?

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by dbr » Thu Nov 09, 2017 10:09 am

dodgy55 wrote:
Thu Nov 09, 2017 9:45 am
Had our home for about 10 years now and I was thinking maybe this is the time to think about installing a new hot water tank. I am guessing the tank is around 12 years old. Water is heated by natural gas. Since it is just myself, wife, clothes washer, and dish washer I was considering swapping to a 30 gallon tank. Not sure if the savings would justify the occasional lack of sufficient hot water. Has anyone had experience changing to a 30 gallon tank and found it worth the effort?
Experience going the other way, actually to 50 gal. I just laugh when my wife worries about both of us taking showers while the washer is running. Your choice would seem odd to me. Do you ever have guests in the house?

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by rec7 » Thu Nov 09, 2017 10:16 am

I have a 40 and am going to a 30 once mine wears out. I can save about $100 a year. I should have done it a long time ago but I hate to get rid of something that is working. My father once ran a duplex on one 30 gallon tank. Remember the key is timing. Since he lived in the other half. He just noted the time they showered. Then went before or after them giving the tank time to recover.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Pajamas » Thu Nov 09, 2017 10:24 am

Gas water heaters are significantly faster than electric water heaters and smaller water heaters are more efficient than larger ones. Newer water heaters are also faster than older ones.

Dish and clothes washers are also much more efficient in water usage than they used to be and most newer showers are low-flow compared to older ones. Specific detergents are also available for washing clothes in cold water. So overall, households use much less hot water than they did twenty years ago.

A modern, thirty-gallon gas water heater should provide enough water for two people to take showers and also run a dishwasher or clothes washer. If you do all of those simultaneously and don't use hot water efficiently (old appliances, high-flow shower heads) or have frequent guests or otherwise have a higher demand during short periods of time, you should go with the forty-gallon heater.

This page has instructions on how to estimate your peak hot water usage so you can decide which size to get:

https://energy.gov/energysaver/sizing-new-water-heater

Then if you look at the energy label on water heaters, they state how many gallons of hot water they can produce in an hour so you can compare. ("first-hour rating")

When I replaced my older refrigerator a few years ago, it paid for itself in savings on the electric bill in less than three years, so I wish I had done it sooner.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Teague » Thu Nov 09, 2017 10:28 am

A 30 gallon tank heater may work better for showers than a 40 gallon. It's not all about size - it's about the recovery rate.

Lots of info, maybe more than you want, at:

http://www.waterheaterrescue.com/genera ... -page.html
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Sandtrap » Thu Nov 09, 2017 10:31 am

Went from a 50 to a 90 gallon gas.
Didn't notice the difference in gas use, but did notice the difference in hot water availability. Washing machine. Dishwasher. Also use hot water.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by clutchied » Thu Nov 09, 2017 10:35 am

cost to run is de minimis.

Get something that you're comfortable with. I wouldn't ever go smaller.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Swansea » Thu Nov 09, 2017 11:23 am

I replaced my 40 gallon with another 40 gallon tank this year...same brand. The new tank did not fill my deep tub with enough hot water, while the old one did...same setting.
My conclusion was that the normal setting was some degrees less in order to save energy, so I turned it up and all was well. Moral of the tale is a newer tank may have different (lower) heating ability...something to check into.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by hand » Thu Nov 09, 2017 11:35 am

Pajamas wrote:
Thu Nov 09, 2017 10:24 am
Gas water heaters are significantly faster than electric water heaters and smaller water heaters are more efficient than larger ones. Newer water heaters are also faster than older ones.

Dish and clothes washers are also much more efficient in water usage than they used to be and most newer showers are low-flow compared to older ones. Specific detergents are also available for washing clothes in cold water. So overall, households use much less hot water than they did twenty years ago.

A modern, thirty-gallon gas water heater should provide enough water for two people to take showers and also run a dishwasher or clothes washer. If you do all of those simultaneously and don't use hot water efficiently (old appliances, high-flow shower heads) or have frequent guests or otherwise have a higher demand during short periods of time, you should go with the forty-gallon heater.

This page has instructions on how to estimate your peak hot water usage so you can decide which size to get:

https://energy.gov/energysaver/sizing-new-water-heater

Then if you look at the energy label on water heaters, they state how many gallons of hot water they can produce in an hour so you can compare. ("first-hour rating")

When I replaced my older refrigerator a few years ago, it paid for itself in savings on the electric bill in less than three years, so I wish I had done it sooner.
+1

If you want to downsize (or rightsize) take the time to understand your demand profile (usage) before simply deciding to make a change.
Once you understand your demand, you can determine appropriate size and recovery rate appropriately.

For a small household with occasional peaks, you may want to consider a smaller tank, but a "high recovery rate" unit to reduce standby "losses" during normal use. Note that "savings" of a smaller unit may be illusory as "extra" cost of wast heat is likely heating your house during cool months.

Also, be sure that the unit you buy works as desired during power outages - many higher efficiency gas units require electrical power to operate which may or may not be important for you.

Finally, be clear whether any potential savings for downsizing are worth the risk of your wife running out of hot water in the shower...

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by ThatGuy » Thu Nov 09, 2017 11:52 am

Grt2bOutdoors wrote:
Thu Nov 09, 2017 10:03 am
WhyNotUs wrote:
Thu Nov 09, 2017 9:52 am
Do you mean worth it in terms of dollars saved from energy cost?
From an energy perspective, the difference between a 12 year old tank and a new tank is probably greater than the difference between 30 and 40. You could also buy a 40 gal that uses less energy than a 30 gallon. Each one has a label on it with expected annual energy cost for comparison.

A tankless system would give you energy savings, space savings, and more hot water but it not well suited for every application.
Not to hijack thread, but am also thinking of replacing my now 10 year old tank. How does one compare a tankless system with the output of a 40 gallon unit? I also use natural gas.
Be aware that any tankless gas heater is going to require exhaust ducting to the outside. I currently have a tankless which I very much like, in particular the possibility of running out of water is nil as long as the water department holds up their end of the bargain.

For others who use electricity, I would recommend a heat pump heater instead of a tankless. These work by pulling heat out of the surrounding air and transferring it to the water. Moving heat is more efficient than generating heat. In the case of a heat pump, it is actually more efficient to go with a bigger unit, as the surface area to volume ratio is much smaller.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by michaeljc70 » Thu Nov 09, 2017 11:56 am

If you have to turn up the 30 gallon higher to have enough hot water, you aren't going to save anything. I wouldn't do it. The cost savings will be minimal anyway and 40 gallons is pretty standard in the US. I have 40 now, but had a 75 at my last house because it was a larger home.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by mmmodem » Thu Nov 09, 2017 12:00 pm

We went to a smaller water heater. Our plumber recommended it.

We have 4 adults and two children living in the home. We have guests all the time. After a get together, my sisters' family often have their kids take a bath at our place before going home so they could go straight to bed. We used to run out of hot water occasionally. Since the replacement, I can't recall the last time it happened.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by dcabler » Thu Nov 09, 2017 12:08 pm

Count us in the going in the other direction group. We did it because we had the main tank in the garage and a small satellite tank in the attic at the far end of the house - the vision of the small tank having a catastrophic failure and taking out the ceiling in multiple rooms caused me to abandon it and enlarge the tank in the garage. When it croaks will consider going tankless....

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by 123 » Thu Nov 09, 2017 12:27 pm

The only potential reason to downsize a water heater would be that a same-size replacement won't fit. Newer water heaters are larger due to energy efficiency and more insulation. Before I would downsize I would carefully evaluate the recovery rate.

If you every sell your house having only a "baby" water heater will alienate some buyers. People will wonder where the "real" water heater is. For those of us into plumbing nothing makes a prospective house seem more potentially comfortable thank knowing that there's a big tank of hot water ready for our use.

Edited to add:
It's quite possible that a smaller water heater will be more expensive to purchase, or may not be as readily available, simply because of the more limited market for them in some areas.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Pajamas » Thu Nov 09, 2017 12:34 pm

123 wrote:
Thu Nov 09, 2017 12:27 pm
The only potential reason to downsize a water heater would be that a same-size replacement won't fit.
There are many reasons to choose a smaller water heater if it is the appropriate size.

A smaller water heater costs less initially.
It costs less to run as it is both more efficient and has to keep less water hot.
The lower energy use creates less pollution.
The size should also have a small effect on air conditioning and/or heating costs depending on where it is located in the house and the local climate.

Getting the right size air conditioning or heating unit produces similar benefits. Any appliance that is too large or too small is inefficient in many ways.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by itstoomuch » Thu Nov 09, 2017 12:36 pm

We went tankless 3 decades ago.
We also went to bidetseats with hot water feature. (the endless warm water bidet crapped out and now we have a reservoir bidet that requires 2 minutes to reheat :| )
We take our showers at the gym.
We use paper plates, paper cups, and plastic ware.

JMO, a 15gal tank is enough :greedy :mrgreen:

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by sunny_socal » Thu Nov 09, 2017 3:06 pm

So I went to the Home Depot website and compared Rheerm 30 and 40 water heaters in the same tier ("Performance")
30gal: XG29T06EC32U1
40gal: XG40T06EC36U1
Pajamas wrote:
Thu Nov 09, 2017 12:34 pm
There are many reasons to choose a smaller water heater if it is the appropriate size.

A smaller water heater costs less initially.
Perhaps, but in the above comparison the 40gal was $409 and the 30gal was $449.

In my case (went from 40gal to 50gal) the larger unit was only about $100 more.
It costs less to run as it is both more efficient and has to keep less water hot.
Perhaps - but once you have a large quantity of water heated it acts like a battery. The larger heater will cycle less often.
Also the 'energy factor' between the two units I compared is virtually identical (0.60 vs 0.59) I'll bet there's not much difference in efficiency when looking at units within the same Tier.
The lower energy use creates less pollution.
Perhaps. Natural gas burns very cleanly, this isn't much of a concern either especially when the efficiency of the units is about the same.
Getting the right size air conditioning or heating unit produces similar benefits. Any appliance that is too large or too small is inefficient in many ways.
I'll agree with you on the Heating/AC issue, here the size is much more critical. But we're talking about an active heating/cooling system, a water heater also has a storage unit with it. The comparison to an AC system should be linked to a Tankless water heater.

I still think that the added capacity of a larger water heater is more important than the other factors you listed. I installed the largest unit that would fit in my closet and now we never run out of hot water! :beer

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Pajamas » Thu Nov 09, 2017 3:55 pm

sunny_socal wrote:
Thu Nov 09, 2017 3:06 pm
So I went to the Home Depot website and compared Rheerm 30 and 40 water heaters in the same tier ("Performance")
30gal: XG29T06EC32U1
40gal: XG40T06EC36U1
It's almost always possible to find specific examples to prove whatever you want! :beer

tesuzuki2002
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by tesuzuki2002 » Thu Nov 09, 2017 3:59 pm

Speaking of water heaters.... what is the recommended time to replace them. I have one that is 13 years old. Still works fine.. Should I consider replacing?

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by bob60014 » Thu Nov 09, 2017 5:50 pm

Don't forget to check local building codes regarding minimum size! Also when you go to sell a sharp inspector will zing you. Why mess around? Stay with a 40 or upgrade to a 50.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by cal91 » Thu Nov 09, 2017 6:15 pm

Point wrote:
Thu Nov 09, 2017 10:03 am
Insulate the tank with a good water heater blanket and don’t sweat it
I have not heard of this, but it seems so logical I can't believe I haven't thought of it. Is this pretty effective for increasing efficiency? Where would I buy a blanket.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by cherijoh » Thu Nov 09, 2017 6:53 pm

cal91 wrote:
Thu Nov 09, 2017 6:15 pm
Point wrote:
Thu Nov 09, 2017 10:03 am
Insulate the tank with a good water heater blanket and don’t sweat it
I have not heard of this, but it seems so logical I can't believe I haven't thought of it. Is this pretty effective for increasing efficiency? Where would I buy a blanket.
I think I found mine at one of the big-box home improvement stores.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Teague » Thu Nov 09, 2017 6:57 pm

tesuzuki2002 wrote:
Thu Nov 09, 2017 3:59 pm
Speaking of water heaters.... what is the recommended time to replace them. I have one that is 13 years old. Still works fine.. Should I consider replacing?
I would plan on replacing sometime in the reasonably near future, especially if you've never changed the anode (a rod of sacrificial metal that prolongs the tank life.)
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by WhyNotUs » Thu Nov 09, 2017 7:08 pm

cal91 wrote:
Thu Nov 09, 2017 6:15 pm

I have not heard of this, but it seems so logical I can't believe I haven't thought of it. Is this pretty effective for increasing efficiency? Where would I buy a blanket.
Check with your utility provider, they often have giveaways in our area.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by WhyNotUs » Thu Nov 09, 2017 7:10 pm

Pajamas wrote:
Thu Nov 09, 2017 3:55 pm
sunny_socal wrote:
Thu Nov 09, 2017 3:06 pm
So I went to the Home Depot website and compared Rheerm 30 and 40 water heaters in the same tier ("Performance")
30gal: XG29T06EC32U1
40gal: XG40T06EC36U1
It's almost always possible to find specific examples to prove whatever you want! :beer
It is common sense that heating and holding the temperature on 40 gals of water will require more energy than 30 gals of water if other things are equal no need to find an odd example.
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by rebellovw » Thu Nov 09, 2017 7:13 pm

We just replaced ours about a month ago - same size. The new one seems like a real beast and has great reviews - AO Smith. It has a sacrificial rod that can be replaced I believe every year - I'm going to try to do that myself -hopefully extend the life of it.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Pajamas » Thu Nov 09, 2017 7:41 pm

WhyNotUs wrote:
Thu Nov 09, 2017 7:10 pm
It is common sense that heating and holding the temperature on 40 gals of water will require more energy than 30 gals of water if other things are equal no need to find an odd example.
I agree with you 100% but you seem to be confused about what the odd examples were used to prove. 8-)

It actually doesn't surprise me that a 30 gallon version of a 40 gallon model costs more at a retailer like Home Depot. Part of their pricing is based on purchase volume and competition with other retailers, so there are anomalies such as charging more for an odd filter size vs. a common filter size even though the odd size is significantly smaller than the common size. 40 gallon water heaters are much more popular than 30 gallon water heaters.

However, the total cost over the life cycle is the best measure for cost comparison, not initial cost.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by TLB » Thu Nov 09, 2017 7:44 pm

The reason you might find the 40 gal WH a little bit cheaper than the 30 gal is because the 40 is a lot more popular for new construction. I’m a Plumbing Contractor in So Ca and in the last 40 years I have never installed a 30 gal WH in a new home. I would stay with a 40 gal WH if it will still fit, newer ones are all built with R16 insulation, if I remember right. In the last three years we have only installed tankless Heaters. The only problem retrofitting to a tankless WH is that you will more than likely have to increase your gas size to ¾” and change your vent material.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Watty » Thu Nov 09, 2017 8:02 pm

My natural gas water heater is 13 years old so I just scheduled getting it replaced next week.

It was a 50 gallon and I am replacing it with another 50 gallon even though there are just two of us in the house now.

My reason for not downsizing to a 40 gallon is that we will likely be moving in the next few years and we didn't want having the smaller tank be a negative if a large family buys our house.

It is interesting that the company charges the same for either a 40 or 50 gallon tank.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by hightower » Thu Nov 09, 2017 8:07 pm

Go tankless! Well worth it. Will use a lot less energy than regular tank heaters. Ours is incredible and we never run out of water.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by meebers » Thu Nov 09, 2017 8:19 pm

I always thought that local code dictates what size of Water Heater. I have 4BR, 3 bath house, 2500 sft, calls for a 55 Gal. Luckily we have natural gas, 2 of us at the moment, Water heater and Fireplace uses NG. Our monthly bill is usually between $25-30 with half of the cost tied up in local fees/taxes etc. Converting to a NG tank less heater would not save anything? and we would never recoup the cost. Tank is in the garage, has no blanket etc. People up north would have a different experience.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by tibbitts » Thu Nov 09, 2017 8:36 pm

hightower wrote:
Thu Nov 09, 2017 8:07 pm
Go tankless! Well worth it. Will use a lot less energy than regular tank heaters. Ours is incredible and we never run out of water.
You can't say that unless you know the usage and the infrastructure already in place. It's easy to spend many thousands of dollars just to prep an existing house for a tankless heater, without even buying the device. I have an old conventional gas water heater and pay almost nothing to heat water above the baseline minimum gas charge per month.

On the other hand, almost all traditional water heaters grew a couple of inches in circumference a couple of years ago, so you can spend a lot making your house accommodate them, too. There's at least one brand that makes a line of backward-compatible skinny models but of course they're more expensive than you can buy an otherwise-comparable new fatter model for.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by hightower » Thu Nov 09, 2017 8:57 pm

tibbitts wrote:
Thu Nov 09, 2017 8:36 pm
hightower wrote:
Thu Nov 09, 2017 8:07 pm
Go tankless! Well worth it. Will use a lot less energy than regular tank heaters. Ours is incredible and we never run out of water.
You can't say that unless you know the usage and the infrastructure already in place. It's easy to spend many thousands of dollars just to prep an existing house for a tankless heater, without even buying the device. I have an old conventional gas water heater and pay almost nothing to heat water above the baseline minimum gas charge per month.

On the other hand, almost all traditional water heaters grew a couple of inches in circumference a couple of years ago, so you can spend a lot making your house accommodate them, too. There's at least one brand that makes a line of backward-compatible skinny models but of course they're more expensive than you can buy an otherwise-comparable new fatter model for.
That’s actually not true. It doesnt cost much to install one of the these. I did ours myself. All that was needed was to run some PVC vents and add a new electric circuit. Everything else is already there (gas and water supply). The unit, a install kit, and a few cheap items from HD is all needed.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by VaR » Thu Nov 09, 2017 9:17 pm

sunny_socal wrote:
Thu Nov 09, 2017 3:06 pm
Also the 'energy factor' between the two units I compared is virtually identical (0.60 vs 0.59) I'll bet there's not much difference in efficiency when looking at units within the same Tier.
The 0.01 difference in energy factor represents the additional standby loss of the 40 gallon tank. The formula to convert that into dollars.

365 X 41045 ÷ EF X Fuel Cost (Btu) = estimated annual cost of operation

Note that the constant 41045 is the number of BTUs to heat 64.3 gallons of water from 58 F to 135 F. This is allegedly the average amount of hot water a household of 3 people uses per day.

You can use this info to decide whether you want to downsize. The 1.67% savings doesn't sound worth it to me. I would buy the 40 gallon one and then turn the standby temperature down to medium-low.

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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by jumppilot » Thu Nov 09, 2017 9:49 pm

My whole life, in all the places I've lived, I've only had one water heater installed.

Fast forward to a new house we had built that came with two 40 gallon gas water heaters in series.

It was a life changer.

We never ran out of hot water and truth be told my gas bills weren't very high. The morning after a Christmas party, where responsible adults stayed over night, we had 3 showers running at the same time and we never ran out of hot water.

So my vote is ditch the 30 gallon idea and go big and go in series! :sharebeer

tibbitts
Posts: 6945
Joined: Tue Feb 27, 2007 6:50 pm

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by tibbitts » Thu Nov 09, 2017 11:10 pm

hightower wrote:
Thu Nov 09, 2017 8:57 pm
tibbitts wrote:
Thu Nov 09, 2017 8:36 pm
hightower wrote:
Thu Nov 09, 2017 8:07 pm
Go tankless! Well worth it. Will use a lot less energy than regular tank heaters. Ours is incredible and we never run out of water.
You can't say that unless you know the usage and the infrastructure already in place. It's easy to spend many thousands of dollars just to prep an existing house for a tankless heater, without even buying the device. I have an old conventional gas water heater and pay almost nothing to heat water above the baseline minimum gas charge per month.

On the other hand, almost all traditional water heaters grew a couple of inches in circumference a couple of years ago, so you can spend a lot making your house accommodate them, too. There's at least one brand that makes a line of backward-compatible skinny models but of course they're more expensive than you can buy an otherwise-comparable new fatter model for.
That’s actually not true. It doesnt cost much to install one of the these. I did ours myself. All that was needed was to run some PVC vents and add a new electric circuit. Everything else is already there (gas and water supply). The unit, a install kit, and a few cheap items from HD is all needed.
It is true for many people who select either an electric or gas tankless heater. First, it's true that if you d-i-y the cost will be much less, but it's not reasonable to expect the vast majority of people to do that. Many houses will require additional electrical service from their supplier to operate an electrical tankless. In order to add even a lower-capacity circuit to my house recently I had to have my service increased and replace the panel with a higher-capacity one. There were only slightly cheaper alternatives - and doing that was expensive. Although I've run outlets, replaced breakers, etc. I'm not going to d-i-y adding another 100amps to my service. As for gas, I investigated that too and would have needed to upgrade multiple components in my gas system to meet the specs for a tankless heater. Again you can say you can d-i-y that but the vast majority of people aren't going to do that.

Now, in new construction you can argue that the marginal cost for a tankless upgrade would not be very much, and that's probably true.

mouses
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by mouses » Thu Nov 09, 2017 11:21 pm

It was a happy day when I had the old 30 gallon hot water heater replaced with a 40 gallon one, never again running out of hot water.

MnD
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Joined: Mon Jan 14, 2008 12:41 pm

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by MnD » Thu Nov 09, 2017 11:32 pm

Just get 220V electric shower heads and skip the tank.
Very popular in emerging market countries!

Image

http://johnnyvagabond.com/travel-tips/s ... de-shower/

quantAndHold
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Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by quantAndHold » Fri Nov 10, 2017 12:31 am

rec7 wrote:
Thu Nov 09, 2017 10:16 am
I have a 40 and am going to a 30 once mine wears out. I can save about $100 a year. I should have done it a long time ago but I hate to get rid of something that is working. My father once ran a duplex on one 30 gallon tank. Remember the key is timing. Since he lived in the other half. He just noted the time they showered. Then went before or after them giving the tank time to recover.
I assume you have an electric hot water heater? My 15 year old, 40 gallon gas water heater only costs us about $9/month to run (2 adults). It would be very difficult to save $100 a year on hot water unless we just stopped using hot water completely.

Valuethinker
Posts: 33159
Joined: Fri May 11, 2007 11:07 am

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Valuethinker » Fri Nov 10, 2017 4:14 am

dodgy55 wrote:
Thu Nov 09, 2017 9:45 am
Had our home for about 10 years now and I was thinking maybe this is the time to think about installing a new hot water tank. I am guessing the tank is around 12 years old. Water is heated by natural gas. Since it is just myself, wife, clothes washer, and dish washer I was considering swapping to a 30 gallon tank. Not sure if the savings would justify the occasional lack of sufficient hot water. Has anyone had experience changing to a 30 gallon tank and found it worth the effort?
I think the consensus is this is not a good idea for reasons of convenience and resale (would put off some buyers, potentially).

New tanks are very energy efficient - you can get one with excellent insulation (one form of loss is via the ground, so insulated feet help). Energy consumption thus similar. Cost of a 40 gallon and a 30 gallon should be similar.

Your main problem may be a change in dimensions *that* could force you to downsize.

The real alternative is to go tankless. A lot of considerations there, for a couple that should work but it will have inconvenience. I am a fan of sticking to what works (i.e. retain current approach, get a new highly insulated tank)-- avoids having to replace the burner.

jerryk68
Posts: 94
Joined: Wed Jan 22, 2014 7:56 pm

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by jerryk68 » Fri Nov 10, 2017 8:15 am

Many years ago went from an electric 80 or 85 gal tank to a 40 gal tank without any trouble. Just do the mental math. For me it was usually 1 shower at 6AM, 2 showers at 7AM and one at 9AM. In between showers the tank recovered. Laundry and dishwasher usually ran at other times. I never needed to adjust the temperature of the water and never ran out of hot water. Why pay for a large tank when it's not really needed?

neilpilot
Posts: 1029
Joined: Fri Dec 04, 2015 1:46 pm
Location: Memphis area

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by neilpilot » Fri Nov 10, 2017 8:20 am

Valuethinker wrote:
Fri Nov 10, 2017 4:14 am

I think the consensus is this is not a good idea for reasons of convenience and resale (would put off some buyers, potentially).

New tanks are very energy efficient - you can get one with excellent insulation (one form of loss is via the ground, so insulated feet help). Energy consumption thus similar. Cost of a 40 gallon and a 30 gallon should be similar.

Your main problem may be a change in dimensions *that* could force you to downsize.

The real alternative is to go tankless. A lot of considerations there, for a couple that should work but it will have inconvenience. I am a fan of sticking to what works (i.e. retain current approach, get a new highly insulated tank)-- avoids having to replace the burner.
I'm mostly in agreement except at the end when you suggest you avoid "having to replace the burner ". What gas water heater has an option of a tank replacement without an integral burner?

BTW other's have posted about "hot water heater". I have 2 water heaters, but they both heat cold water.

rec7
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Location: ST LOUIS

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by rec7 » Fri Nov 10, 2017 10:16 am

quantAndHold wrote:
Fri Nov 10, 2017 12:31 am
rec7 wrote:
Thu Nov 09, 2017 10:16 am
I have a 40 and am going to a 30 once mine wears out. I can save about $100 a year. I should have done it a long time ago but I hate to get rid of something that is working. My father once ran a duplex on one 30 gallon tank. Remember the key is timing. Since he lived in the other half. He just noted the time they showered. Then went before or after them giving the tank time to recover.
I assume you have an electric hot water heater? My 15 year old, 40 gallon gas water heater only costs us about $9/month to run (2 adults). It would be very difficult to save $100 a year on hot water unless we just stopped using hot water completely.
Ours is natural gas. I got those numbers off the yellow energy stickers.
Disclaimer: You might lose money doing anything I say. Although that was not my intent. | Favorite song: Sometimes He Whispers Jay Parrack

michaeljc70
Posts: 1955
Joined: Thu Oct 15, 2015 3:53 pm

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by michaeljc70 » Fri Nov 10, 2017 10:30 am

rec7 wrote:
Thu Nov 09, 2017 10:16 am
I have a 40 and am going to a 30 once mine wears out. I can save about $100 a year. I should have done it a long time ago but I hate to get rid of something that is working. My father once ran a duplex on one 30 gallon tank. Remember the key is timing. Since he lived in the other half. He just noted the time they showered. Then went before or after them giving the tank time to recover.
Are you comparing apples to apples? In other words, a new 40 gallon vs a new 30 gallon?

My 18 year old 50 gallon inefficient water heater says it cost $168 a year to run. That's why it seems unlikely moving from a 40 to 30 gallon would save $100 a year. But maybe you live somewhere with high gas prices.

Valuethinker
Posts: 33159
Joined: Fri May 11, 2007 11:07 am

Re: Worth changing 40 gal. to 30gal. hot water tank?

Post by Valuethinker » Fri Nov 10, 2017 10:33 am

[edited duplicate post]
Last edited by Valuethinker on Fri Nov 10, 2017 10:33 am, edited 1 time in total.

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