Why not plumb all supply with 3/4 PEX?

[c88]

Is there any reason not to do this? I know pipe size does not affect pressure so would more pipe size be better and easier to install given its all the same size?

-lav
-sink
-toilet
-urinal
-3 bibs
-fridge
-2 showers
-washing machine
-water heater

 

[Reach4]

3/4 is stiffer and harder to work with than 1/2 inch.

For hot water, it takes twice as long for the hot to hit the faucet. Urinal, I don't know. Is 3/4 enough? Regular toilet, 1/2 or 3/8 is good.

Water heater should have 3/4 or bigger, but many people consider it best not to run the PEX right to the WH. I don't know what is considered good practice for Florida. Don't put your plastic pipe out in the sun. Protect it somehow, such as with paint.

 

[Sponsor]

 

[WorthFlorida]

If you homerun everything from a manifold, you need 3/4" in but 1/2" out and that is the way they are made for a reason. All fixtures are 1/2" anyway. Homes in Florida with pipe under the slab are 3/4" to a point. When they come out of the floor, and need to feed two sinks, toilets, etc, a 3/4" x 1/2" x 1/2" tee is used. If you want to daisy chain to the next fixture to another room you can continues with 3/4" with 3/4" x 1/2" x 3/4" tee.

https://www.pexuniverse.com/pex-tubing-technical-specs

 

[Jadnashua]

Static pressure (no flow), will be the same everywhere except potential height differences and gravity effects. Dynamic pressure DOES vary depending on the diameter, length, number of fittings, and flow rate. There are a few things in a typical home that are not flow restricted: tub, outside hose bibs are the two most common. Most everything else is flow restricted. Then, you need to consider on a typical day, how many things will be drawing water at the same time. You have to decide whether you want a worst case situation, or can live with potential reduction in pressure and maybe volume if numerous things are opened up at the same time. Something like a shower with a lot of body sprays and shower heads would be overwhelmed by a 3/4" pex line and probably a 3/4" copper one as well...so, you need to evaluate your needs and desires.

A hot water recirculation system will negate any delay in the arrival of hot water and can save in both energy and resources. On a long run, that can cool off in between uses, you might be wasting 2-3 gallons or more each time you want hot water. That adds to your utility bill, decreases the useable volume in your water heater, and can be an issue in areas where water is more precious. Make sure to insulate the lines. It may make sense to put it on a timer if your typical day allows it.

 

[Jbrk]

I got caught once when I designed a double faucet lav and forgot to include an extra outlet at the manifolds. So I have 1" manifolds then a 1/2" outlet that tees to both faucets. So I get the annoyance of one faucet will effect the other when operating them both.

Pipe size doesn't effect static pressure, but it effects flow or available water.

So to your question, I'd say sure, run 3/4" supplies and then tee off to 1/2" to each fixture. I personally won't run two fixtures off one 1/2" line anymore. Unless one of them is something innocuous like an ice maker off a hose bib or something.

 

[c88]

Thanks for your thoughtful replies, after learning to redo the electrical I expected plumbing to be easier.. I was wrong, plumbing can be down right confusing! Your help is appreciated.