I am going to replace my old, conventional gas furnace and gas water heater in
about two weeks. Now comes the part where I do my homework - studying I have
NEVER done (furnace) and only once, briefly, for a water heater.
My contractor has recommended that, now that our home is occupied only by me
and my wife, we downsize the gas water heater from its current 50-gallon
capacity to a forty.
Although our home has one full and two "3/4" baths, the shower in the finished
basement is virtually never used. We only occasionally have overnight guests
but, with three grown daughters (two with children), we VERY-occasionally
(rarely, really) have four adults and little kids for a few nights.
Obviously, I do not want to REGRET downsizing. The fifty-gallon gas water
heater I have now was a "spec" unit when I bought this home while half-built -
a spec house. The new one I am considering is called a "forty" but is rated
at 38-gallons with a "high recovery" rate of 48 atop a 50k burner.
Will this one do the trick for us, with a little PLANNING done when the kids
are here (VERY rare for overnight/shower/laundry use)? TIA!
It should. Million of homes have only a 40 and have no problems.
The cost issues are:
Cost to buy a 50 over a 40
The cost of the heat loss of having 50 gallons sitting versus 40 gallons My
first house had a 30 with two kids we never had a hot water problem. In
winter the heat loss is not an issue either.
Operating cost will be the same given they would be equal efficiency. It
takes X amount of Btu's to heat a gallon of water from the entry temperature
to the set temperature no matter how many gallons are in reserve.
I would downsize. I have a 40 gallon. Even when the kids and their
spouses come to visit (total of 6 adults) that 40 gallon heater has no
problems keeping up with day to day use including the extra laundry. Maybe
with a dishwasher, it might be pushed at times, but so far no such problems.
Remember that not all water heaters have the same recovery rate. Older
electric heaters often had a slower recovery rate so they needed more
capacity. Most gas water heaters today recover quickly.
The recover rate for a 40 gal. Bradford White is 41gph, and a 50 gal. is
51gph. My price for a 50 gal. is about 15% higher than a 40 gal. With new
insulated tanks, the heat loss for the extra 10 gallons is minimal. Most
families are fine with a 40 gallon. If you had more people, I'd recommend a
50 gal., because extreme temperature differences can shorten the tank life.
Go with the 40- that's plenty for two people You can just turn the hot water
thermostat up when the kids and grandkids come-- that's what we do.
Remember to turn it back down when they leave though.
we have 75 gallons, gas, 150 degrees, 4 adults, dog, washing machine,
dishwasher. heavenly. in buffalo ny our water arrives in winter at 33
degrees from lake erie, so the degrees of recovery rate has to go from
33 to 150 not the usual specified rise you are referring to. maybe
you're in a warmer climate and the rise is small.
you shouldn't bother replacing the tank until it fails or leaks. then
go with the energy recovery you speak of and put it on a drain pan with
a drain pipe.
or even the pilotless 24 volt thermostat operated tank. or really
modern with a big rinnai tankless.
here's a funny rule for you: allow 10 gallons each per person and
dishwasher and washer, add household female hair length in total inches
for additional gallons needed. but teenagers will drain a hot water
tank, so let them shower last.
[if you quietly check the cold water temp and hot water temp before her
shower, time her shower, and measure the hot water temp at the end of
her shower you will have the data subject to your season of the year.
if she catches you she will divorce you. :)
if anyone takes a tub bath, all size estimates are off just buy the
biggest tank you can get thru the doorways.
50 gallon all the way
you can keep the temp a little lower with more storage
and with the high efficiency models, you wouldnt even notice the fuel
difference against a 40...very minimal
and if you want to sell the house, it sounds a whole lot better saying
you have a 50 gallon water heater.
Have you looked into a tankless? Around $600-1000, but much more
efficient - you don't have a bunch of water just sitting there warm
most of the time. Then it's unlimited hot water when you do use it.
Something to think about.
My wholesaler sells Rinnai tankless water heaters. They tell me they're
great for a single bathroom, but they've gotten a lot of complaints when
installed on a whole house system. I don't know about other brands, but my
guess is that they're about the same.
I have an older home with "utility basement", the only W/H that fits
throught he door & down the stairs is a 30. Another home had the W/H in
a SMALL closet, the old 40 fit but the modern 30 was the biggest unit
thta fit w/o taking the clost face off.
SInce both homes are in SoCal cold water is rarely very cold.
The size of your water heater will be driven by:
inlet water temp
if you "demand spread" & your inlet water temp is not ice cold: a 30
will work just fine
If your inlet temp is COLD, you'll need more capacity
A high recovery rate W/H can nearly keep up with ~1gpm hot water
Jim Redelfs wrote:
Boy I wouldnt downsize! The larger tank costs so little more. you might
get a houseguest at any time, that happened here, friends had a
housefire, 2 people and their dog for 7 months, upon house resale the
bigger tank is a advantage too. as other have said the bigger tank you
can leave the water cooler saving energy costs, and tanks last longer
too. they are thermally stressed less when larger. smaller tanks have
wider temp swings which is tough on the porcelin inner coating.
A good way to save $ is adding a hot water heater blanket, and
insulating the hot water lines too.
Oh, rats! I thought I had made-up my mind, now I'm not sure (again).
Thanks to everyone that replied. As a newbie to this NG, I was pleasantly
surprised to read so many prompt replies and not a flame among them - or
between them. Good show! :)
Has anyone REALLY "done the math" when considering: Lowering the water heater
storage temp, I must then turn ON the dishwasher's heating elements to achieve
the recommended dishwashing temp? I would chose to lower the tank setting.
That makes sense. I am very disappointed in the relatively short life of my
current water heater. It went into service November 1, 1991. Lessee...
That's about 14-1/2-years. Hmmm... Maybe that isn't so poor a life span for
a minimally (never?)-maintained unit.
I plan to buy a unit with R16 insulation. It will live in our heated laundry
room. (Dog house with utilities!) Subsequent heat loss is of little concern,
even considering that I electrically cool perhaps four months/year. Only a
few of the overall footage of piping COULD be insulated, so that's not much
help in my case. I just wish I'd done it when the place was being built.
Now, on to the selection of a furnace. A first-time thing for me.
Has anyone REALLY "done the math" when considering: Lowering the water
storage temp, I must then turn ON the dishwasher's heating elements to
the recommended dishwashing temp? I would chose to lower the tank
Set at 125 degrees is hot enough for dishwasher, but costs less and is
safer than 150 degree water we used to have to get a little more
capacity out of the tank. mix more cold with hot to get more overall
hot water/ no scald risk either
I am very disappointed in the relatively short life of my
current water heater. It went into service November 1, 1991.
That's about 14-1/2-years. Hmmm... Maybe that isn't so poor a life
a minimally (never?)-maintained unit.
thats a LONG life, and around here theres not much to maintain! Water
is so hard here flushing gets no sediment out of tank, just risks a
leaky drain valve:(
Someone mentioned a higher BTU faster recovery tank. just one problem,
those typically come with shorter warranties:( like 12 years normal;
btu, 6 years high output tank....
You can turn them on and off? I can only turn off the heating
elements for the drying period. When the water is coming in, the
heaters are always on. Are you confusing the two, or do newer dw's
have more switches?
Remove NOPSAM to email me. Please let
me know if you have posted also.
I believe so. I just checked and they're ON after all. <sigh>
We replaced the spec Hotpoint with a top-of-the-line Maytag a few years back.
In addition to "Heated Dry", there is a "Temp Sense" (on/off) available.
Without getting out for the manual (which I read when the thing was
installed), I recall that the Temp Sense monitors wash water temperature and
heats it as needed.
Aw, heck. For enough $$, I'm sure you can get one that displays the Dow Jones
on the half hour! My dishwasher has five switches, including the above
mentioned switches and the main timer/mode selector/dial.
The only option I have for the wash cycle is a Sani Cycle. The difference
being the rinse water is also heated. You really want the wash water heated
so the detergent does the best possible job.
The DW has more cycles that we ever use, but we always use the Sani-rinse.
Well, I'm not arguing with anyone, but I thought I would tell you my
experience. I had a 52 gallon tank and considered downsizing. After
all, I live alone. I have electric, no natural gas available.
But I got the same size the house came with, maybe for resale, maybe
because it fit where the old pipes were, maybe because I'm cautious.
I take baths. I left the temp the way the WH came, and I guess that
is rather low. I'ts too hot to hold my hand in the hot water, but
it's not scalding hot either.
My bathtub is small compared to the big tub I had in Brooklyn. but its
still about 100 gallons. If I fill the tub almost to the brim, with
me lying down, and if I make a mistake and it isn't hot enough and I
drain an inch or two of water, and try to fill it again, I'm often out
of hot water. That's starting with a full 52 gallons of hot water,
I can use it all in less than a half hour.
And my baths are not that hot. They don't even condense on the mirror.
My mother wanted me to learn to take what she called steaming hot
baths, and I tried one because she asked me to, and I got
claustrophobic, and HOT. ( I have been the natural hot baths of
Gader, and those were fine, even in the hot portion, but they were
I could make the water hotter, and never run out, but I like the fact
that I can't scald myself, and I should learn not to make mistakes and
waste rather hot water. (It seems hot enough when I put it in, bu I
stay in the tub usually about a half hour, and the water seems to get
cooler and cooler, faster than it really is cooling. I"m supposed to
leave empty room to add hot water slowly. I'm trying to learn to
remember every time to do that.
Remove NOPSAM to email me. Please let
me know if you have posted also.
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