150' PEX underground run to detached studio

[daviddavid]

hi all

I'm needing to run underground a set of hot and cold from a house to a small studio 150 feet downhill, to supply a bath. I thought about instead of running a single cold water line that far, put in an electric tankless, but the electricity cost is extremely high, especially for a 60gal tub! So for now, the plan was to sleeve each 3/4 PEX in it's own pipe, maybe use Uponor Wirsbo hePex hydronic heating pipe w some insulation.

I'm having trouble finding the heat loss information for that long of a run. Would hate to do all that trenching to just get lukewarm water !!

Any thoughts/ lessons learned would be appreciated. Thank you.

 

[cdherman]

How expensive is water? The water will get hot eventually, but you may waste a fair number of gallons. The 60 gal tub is actually not the problem -- you can turn on the hot full bore and it will all even out in the end. BUT I bet there is a shower. And someone will drain 20 gallons of water down the drain to get a hot shower. .....

 

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[Breplum]

way too long a run for hot unless you do as a dedicated recirculation loop. BTW, Uponor now advertises ServicePEX grade tubing.
Use a hot button signal for the recirc., not a full time running system.

 

[daviddavid]

Thanks for the replies. Water is on a well, and the waste water just goes back into the well source. The heating & pumping of the water is solar, so the only major waste is time waiting for it to be hot. There is only a tub, no shower. Just a tub. Nothing else.

I hope I'm understanding the recommendation correctly. A recirculation loop means running a return line back to the water heater? So that would be another 150' of lukewarm water pumped back uphill to the heater?

 

[bigb56]

What about a point of use water heater connected to the incoming hot line? It would only have to run till the hot water from the house arrives.