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[email protected] February 9th 06 08:39 PM

How to size water heater(s) in new home.
 
I will be building a 100' long home with water usage at the two ends of the
house.

At one end will be a mostly over the garage apartment for my daughter with
kitchen, bath, laundry. Also there will be a bath with on the first floor
with our kitchen and also laundry and utility tubs in the laundry and
garage.

In the middle will be a 2nd floor guest bath.

On the other end will be a first floor master bath with shower and 72"
jetted tub (Venus II).

A priority is not to have to wait "forever" for hot water to reach a
spigot, especially at the kitchen & lavatory sinks and utility tubs.

I am planning to have a hot water heater in the garage and another under
the master bath (crawl space here will be about 6 feet high due to land
slope).

How large should I make each water heater. Should I have a separate
additional heater for that huge tub and only turn it on when needed?

Many thanks for any knowledgeable help!

Charles Spitzer February 9th 06 09:19 PM

How to size water heater(s) in new home.
 

wrote in message
...
I will be building a 100' long home with water usage at the two ends of the
house.

At one end will be a mostly over the garage apartment for my daughter with
kitchen, bath, laundry. Also there will be a bath with on the first floor
with our kitchen and also laundry and utility tubs in the laundry and
garage.

In the middle will be a 2nd floor guest bath.

On the other end will be a first floor master bath with shower and 72"
jetted tub (Venus II).

A priority is not to have to wait "forever" for hot water to reach a
spigot, especially at the kitchen & lavatory sinks and utility tubs.

I am planning to have a hot water heater in the garage and another under
the master bath (crawl space here will be about 6 feet high due to land
slope).

How large should I make each water heater. Should I have a separate
additional heater for that huge tub and only turn it on when needed?

Many thanks for any knowledgeable help!


some sort of return loop would be easier, and cheaper to run than 2 heaters.

regards,
charlie
http://glassartists.org/chaniarts




PipeDown February 9th 06 10:13 PM

How to size water heater(s) in new home.
 

"Charles Spitzer" wrote in message
...

wrote in message
...
I will be building a 100' long home with water usage at the two ends of
the
house.

At one end will be a mostly over the garage apartment for my daughter
with
kitchen, bath, laundry. Also there will be a bath with on the first
floor
with our kitchen and also laundry and utility tubs in the laundry and
garage.

In the middle will be a 2nd floor guest bath.

On the other end will be a first floor master bath with shower and 72"
jetted tub (Venus II).

A priority is not to have to wait "forever" for hot water to reach a
spigot, especially at the kitchen & lavatory sinks and utility tubs.

I am planning to have a hot water heater in the garage and another under
the master bath (crawl space here will be about 6 feet high due to land
slope).

How large should I make each water heater. Should I have a separate
additional heater for that huge tub and only turn it on when needed?

Many thanks for any knowledgeable help!


some sort of return loop would be easier, and cheaper to run than 2
heaters.

regards,
charlie
http://glassartists.org/chaniarts




A recirculating loop with large primary tank is certainly a good way to do
it (lower up front cost) but if the hot pipes are not very well insulated,
the recirculating line will cause a lot of heat loss and wasted energy
(higher long term cost). An on demand recirculating pump activated when you
push a button as opposed to a pump on a timer or thermostat is more energy
efficient in my opinion (though not as transparent or instant)

Two tanks is acceptable, I would consider plumbing the second tank in series
with the first if located like you say as opposed to two parallel hot
systems aside one cold. The series tank will allow quick delivery of hot
water to distant fixtures and once the hot water from the primary tank
started filling the second one, it would not need to heat as much water
making the system more efficient. You would also effectively have the full
volume of both tanks available to fill a big tub. Hot water branches can
extend from the output of either tank. This configuration may also buffer
the tub/shower supply from other uses like laundry (connected between the
tanks)

A single on demand heater positioned more centrally in the house or two
smaller units plumbed in parallel are also options.

My Guess: A 50gal primary tank and a 30 gal secondary sound like it might
suit your needs. Of course you can go larger but it will effect your energy
bill. The secondary tank only needs to be somewhat larger than the volume
of water in the hot pipe between the two tanks (which isn't much) to work
(prevent any cold water surges at the far end of the house) plus any
additional volume of water you think the attached fixtures need before the
tanks have time to reheat.

There are pros and cons to each configuration. Choose based on price and
performance you feel comfortable with



Joseph Meehan February 9th 06 11:00 PM

How to size water heater(s) in new home.
 
wrote:
I will be building a 100' long home with water usage at the two ends
of the house.

At one end will be a mostly over the garage apartment for my daughter
with kitchen, bath, laundry. Also there will be a bath with on the
first floor with our kitchen and also laundry and utility tubs in the
laundry and garage.

In the middle will be a 2nd floor guest bath.

On the other end will be a first floor master bath with shower and 72"
jetted tub (Venus II).

A priority is not to have to wait "forever" for hot water to reach a
spigot, especially at the kitchen & lavatory sinks and utility tubs.

I am planning to have a hot water heater in the garage and another
under the master bath (crawl space here will be about 6 feet high due
to land slope).

How large should I make each water heater. Should I have a separate
additional heater for that huge tub and only turn it on when needed?

Many thanks for any knowledgeable help!



I would also go with the single HW heater and a return loop. Get the
pipes well insulated or an on demand system.

As for sizing the HW heaters, maybe some more information would be in
order.

How many people how many bath rooms. Dish washer?

How about schedules. Will everyone be using the hot water at the same
time as also running the clothes and dish washers? Any big spas?

--
Joseph Meehan

Dia duit



Doug Boulter February 9th 06 11:34 PM

How to size water heater(s) in new home.
 
wrote on 09 Feb 2006:

How large should I make each water heater. Should I have a
separate additional heater for that huge tub and only turn it on
when needed?


You've left out some of the most critical data.

1) Gas or electric heaters? Gas will recover much more rapidly and
can often be sized smaller.

2) How many in the family, and who are they? Small family, smaller
size. Large family with teenage boys, bigger is better.

--
Doug Boulter

To reply by e-mail, remove the obvious word from the e-mail address

m Ransley February 10th 06 12:03 AM

How to size water heater(s) in new home.
 
Running a circulator no matter how well insulated the piping will waist
alot of energy. Look into 2 Ng tankless Takagi or Rinnai. Water heaters
tanks only have a Energy Factor in the 60s, tankless go into the 90s.


Michael Keefe February 10th 06 04:56 PM

How to size water heater(s) in new home.
 
On 2/9/06 3:39 PM, in article ,
" wrote:

How large should I make each water heater. Should I have a separate
additional heater for that huge tub and only turn it on when needed?



If you're going to heat water with electricity, I would consider an
on-demand type tankless heater. I think they cost around $500 and you'd be
saving some labor on running a lot of extra line and insulation.


[email protected] February 10th 06 09:09 PM

How to size water heater(s) in new home - More info
 
Someone rightly pointed out that I had left our critical info.
Occupants:
Wife & myself
Daughter (in apt.)
Water Heaters
Either Elec or Propane
Elec is much cheaper purchase & Install
Propane expensive too
Propane = Quicker recovery, possible tankless
Apartment (upstairs):
Bath: Tub/shower combo, lavatory, toilet
Kitchen: Sink, D/W
Laundry: Washer/Dryer
Kitchen - pasrtly under apt
Sink, D/W
Small range side Sink
Laundry:
Util sink
Washer/dryer
Garage:
Util sink
==== All above at one end of 100' long house ======
Guest bath (upstairs in middle)
Lavatory, tub/shower combo, use mostly by guests
Master Bed (at far end from the other stuff)
2 Lavatories
72" Jetted Tub
Seperate shower

A priority is not to have to wait "forever" for hot water to reach a
spigot, especially at the kitchen & lavatory sinks and utility tubs.

I am planning to have a hot water heater in the garage and another under
the master bath (crawl space here will be about 6 feet high due to land
slope).

Options:
2 elec water heaters - one at each end - How big should they be?
3 elec water heaters - Separate one for jetted tub - on when needed
2 Tankless propane heaters
Recirculating - rejected 200+ feet of pipe to loose heat from.
plus cost to run pump, etc.
Others?

How large should I make each water heater. Should I have a separate
additional heater for that huge tub and only turn it on when needed?

Many thanks for any knowledgeable help!


buffalobill February 12th 06 11:22 AM

How to size water heater(s) in new home - More info
 
who/what/where/when/why/how: good except your where = climate =
recovery rate.
there are other options for using hvac systems waste heat and an
architect gives you a better answer.
but from cold water 33 degrees in buffalo ny to 150 degrees of hot
water is faster than yours will be on our big 75 gallon natural gas
tank. you'd get two big electric tanks with as many timers as you can
to run the two tank elements in each. and the circulators.
electric hot water has slow recovery, so now that we see you have cheap
electric available you get the largest residential tanks and you don't
run out. you can run the electric recirculator pump on a start time of
day like 15 to 30 minutes before morning shower time. adjust the tank
temperature high enough so you can run as many of the devices as
possible.
see:
http://www.terrylove.com/wh.htm
more at:
http://www.eere.energy.gov/consumer/.../mytopic=12760
heating cooling calculator at:
http://www.hvacopcost.com/


IBM5081 February 14th 06 11:08 PM

How to size water heater(s) in new home - More info
 
My house is 90 feet wide. Two full baths on a 40 gallon on the west
side of the house. Master bath, laundry equipment and kitchen on a 50
gallon on the east side of the house. Both natural gas fueled. The only
time we ran out of hot water was on the west side when older son stayed
in the shower forever. When it turned cold, he got out. Has not
repeated since he left home.
The dishwasher and kitchen sink are farthest from the water heater and
take some time to get hot water coming out.



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