Re-pipe house

[jferello]

Hey all,

I got a burning question here. I want to re-plumb my house with PEX, I just cannot decide what sizes.

Right now I have 1" Poly from my well to my pressure tank, then from the pressure tank to my mainline is 3/4" CPVC. Finally the CPVC terminates into a 1/2" copper mainline that feeds the water heater, powder room, kitchen sink, dishwasher, washer, hose bib and full bath.

Eventually we want to add a second full bath, which would bring us to 2 1/2 baths.

I believe CPVC has the same I.D. issue that PEX has, right? All my filtering equipment is only 3/4" so it would be pointless to run 1" copper or 1" Poly, but 1" PEX would be equal to 3/4" copper, right?

Should I just use 3/4" PEX for all my main lines and then 1/2" to each fixture?

I have a 40/60 pressure switch.

Thanks,
Justin

 

[Jadnashua]

I would consider 1" pex to where you can branch off. If you put a manifold for major groups, run 1/2" pex to the individual fixtures unless you have sometime like a soaker tub or multi-heads in the shower, then 3/4" to it. 1/2" pex to the water heater is just too restrictive, and even 3/4" might be limiting. Most WH have at least 3/4" inlets and outlets (some have larger). Trying to run multiple showers simultaneously when only feeding the WH with 1/2" will be a disappointment, especially if someone else tries to turn on some hot (say the washing machine, dishwasher, or even a sink faucet).

 

[Sponsor]

 

[Magneto]

He's right and your right, the ID of PEX tubing is equivalent. You should look into a 1'' Non-barrier PEX tubing such as this http://www.canarsee.com/pex-plumbin...n-x-300-ft-pex-plumbing-pipe-non-barrier-blue and then branch it off into smaller tubing sizes. This will maintain the flow rate of your water at a decent pressure to your satisfaction. Otherwise you might have steady problems with your water pressure, and will have to repipe once more to get a proper pressure output.

 

[Reach4]

Some people use red for hot, and blue for cold. Not required.

In running to individual fixtures with hot water, smaller diameter will get the hot water to the faucet sooner. You could also think about running a recirculation line while you are running lines. That would save water vs running the tap for a while to get the water hot.

 

[Magneto]

Reach, you are a very intelligent man!

 

[Jadnashua]

The pressure in a static (no water flowing) system will be the same whether you have 1/8" or 6" water supply piping, but the available flow, and therefore friction will increase radically as the pipe gets smaller. Yes, a smaller pipe means less water to flush out to get hot unless you've run recirculation, but it also means a lower volume possible, which, depending on what you're doing, can make the difference between satisfactory and unsatisfactory results. The faster you try to move water through a pipe, the higher the friction, and the less pressure you'll end up with coming out the tap. ANd, it will restrict the maximum volume available. 1/2" pex is good for most single use points as many things in a modern house are flow restricted: vanity and kitchen sink faucets about 2gpm dont' remember the exact number), a single showerhead 2.5gpm, and things like a toilet typically only have a 3/8" line or smaller to them, so they don't flow much, and their tanks these days aren't very big in the first place.

A few things that can generally use all of the volume possible: hose bibs used for watering, filling a tub (typically, only restricted by internal construction and the supply lines), and maybe a washing machine. Otherwise, a smaller pipe, sized for the anticipated volume desired, is prudent...

One study I read concluded that a hot water recirculation system that ran during typical use times during the day and had insulated hot water lines, used both less water overall and used less energy in the process verses a system without recirculation. Keep in mind that when you turn on the hot tap, even though the water coming out at the end point is cold, it WAS heated at one time, and what's going in is cold. So, like in my place without recirculation, if I turned on my shower, it took about 75-seconds if no hot had been used, which means I' d throw away about 4-gallons of water which I also had to pay sewer charges for before I had any hot and could step underneath and begin showering. If you have a well, that's extra water you had to pump out of the ground, too. And, if you're on a septic system, dumping unnecessary water into the septic tank is not the greatest things, either, not counting the wait. In some places, they're now requiring hot water recirculation on new construction from what I've heard. Mine runs on a timer, but in reality, it probably wouldn't be much more to let it run 24/7. But, if the house is unoccupied a good portion of the day, it does make some sense to shut it down for that time.

Bottom line, keeping the pipes smaller than needed for your anticipated use is false economy and can lead to frustrations and poor performance.