Home Repair forum - What size hot water pipe should I use?

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What size hot water pipe should I use?

NoSpam@aol.com

2008-04-03, 9:25 am

I need to run hot water pipes to the various appliances in my home. Some
of the appliances (lavatories, and sinks) will use relatively small amounts
of water at a time but will be used frequently, while others (tubs &
showers) will be used less frequently but will use much more hot water at a
time.

I would like to minimize wasted energy and the time spent waiting for hot
water at sinks and lavatories while still providing sufficient flow. At
tubs & showers, having a good flow rate is more important and the wasted
energy & wait times do not matter so much because of the less frequent use
and large amount of water per use.

Running different size how water lines to the same room is no problem at
all. I realize that, occasionally this will result in having to fill two
pipes but in our situation this will seldom happen. A recirculating system
is not ennergy efficient so I don't want to go that way.

Given the above, what size pipes should I run to:
Sinks & Lavatories:
Tubs/Showers:
Dish washer:
Washing machine:
(Whirlpool tub: 3/4" since valve inlets are 3/4")

Many thanks for any help!

Big_Jake

2008-04-03, 9:25 am

On Apr 3, 6:35 am, NoS...@aol.com wrote:
> I need to run hot water pipes to the various appliances in my home. Some
> of the appliances (lavatories, and sinks) will use relatively small amounts
> of water at a time but will be used frequently, while others (tubs &
> showers) will be used less frequently but will use much more hot water at a
> time.
>
> I would like to minimize wasted energy and the time spent waiting for hot
> water at sinks and lavatories while still providing sufficient flow. At
> tubs & showers, having a good flow rate is more important and the wasted
> energy & wait times do not matter so much because of the less frequent use
> and large amount of water per use.
>
> Running different size how water lines to the same room is no problem at
> all. I realize that, occasionally this will result in having to fill two
> pipes but in our situation this will seldom happen. A recirculating system
> is not ennergy efficient so I don't want to go that way.
>
> Given the above, what size pipes should I run to:
> Sinks & Lavatories:
> Tubs/Showers:
> Dish washer:
> Washing machine:
> (Whirlpool tub: 3/4" since valve inlets are 3/4")
>
> Many thanks for any help!

1/2" for all. At typical pressure, you can get 5-7 GPM from a 1/2"
pipe.

JK

Bill

2008-04-03, 9:25 am

I prefer 3/4 for house piping and 1 1/4 for a main line to the house and to
outside water valves (idea with large main is that you can water outside and
also get good flow inside).

I lived in house once which had all 3/4 pipes. It was great. Water flowed
fast everywhere. I have preferred this ever since.

Keep in mind that crud builds up on the inside of water pipes. So perhaps
with all the crud, the 3/4 pipe actually has 1/2 of remaining space whereas
the 1/2 pipe has maybe 1/4.

Edwin Pawlowski

2008-04-03, 1:26 pm

"Bill" <billnomailnospamx@yahoo.com> wrote in message
>
> Keep in mind that crud builds up on the inside of water pipes. So perhaps
> with all the crud, the 3/4 pipe actually has 1/2 of remaining space
> whereas the 1/2 pipe has maybe 1/4.

Where do you live? Over 30 years and my copper tubing is a clear as the day
it was installed. You do get buildup in galvanized pipes.

S. Barker

2008-04-03, 1:26 pm

1-1/4 is unrealistic for a supply. It's just not done. IF you really did
it, you wasted money. The meter (at best) will only be 1". And it's
probably a 5/8". A one inch feeder line would be optimal, and 3/4 is most
common. (unless you're going over a hundred feet)

s

"Bill" <billnomailnospamx@yahoo.com> wrote in message
news:65k5h1F2g3eeuU1@mid.individual.net...
>I prefer 3/4 for house piping and 1 1/4 for a main line to the house and to
>outside water valves (idea with large main is that you can water outside
>and also get good flow inside).
>
> I lived in house once which had all 3/4 pipes. It was great. Water flowed
> fast everywhere. I have preferred this ever since.
>
> Keep in mind that crud builds up on the inside of water pipes. So perhaps
> with all the crud, the 3/4 pipe actually has 1/2 of remaining space
> whereas the 1/2 pipe has maybe 1/4.
>
>

nicksanspam@ece.villanova.edu

2008-04-03, 5:25 pm

Bill <billnomailnospamx@yahoo.com> wrote:

>I prefer 3/4 for house piping and 1 1/4 for a main line to the house and to
>outside water valves (idea with large main is that you can water outside and
>also get good flow inside).

SMALLER pipes to outdoor valves would make more flow indoors.

Nick

RicodJour

2008-04-03, 5:25 pm

On Apr 3, 5:10 pm, nicksans...@ece.villanova.edu wrote:
> Bill <billnomailnosp...@yahoo.com> wrote:
>
> SMALLER pipes to outdoor valves would make more flow indoors.

Not unless the outdoor valves were open when you went to use the
indoor plumbing. As in most things, it's better to plan ahead and use
a head, than forge ahead.

R

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