Recirculation pump or gravity recirc in 2025?

[Benze]

I am rebuilding my home and am adding an additional floor to the house (approx 1200 sqft) to house a new master-bath (tub + italian shower) and a an additional bathroom with an italian shower. This will bring the house to a total of 6 bathrooms (4bath, 1 powder and 1 laundry+bath).

15years ago, I retrofitted gravity recirc lines to 3 of my most problematic faucets. It worked fairly well; warm water was always fast and easy to get, and hot water took a few more seconds. I never had scorching hot water though and I expect that my check valve on the HW tank wasn't working perfectly (allowing some cold water to rush up the return line when calling for HW).

Today, the house has been stripped bare and am redoing all the plumbing. I am having a tense negotiation with the plumber who doesn't believe in the value of gravity recirc in 2025, and prefers a pump.

My reasoning to stick with gravity is:
- works 24/7 without fail
- no moving parts
- HW is always present
- no mechanical pump to break down
- no extra electrical costs to control pump
- cheaper to run & maintain

That said, the plumber doesn't like gravity loops b/c of the added complexity to plumb (ensuring the slope of the return lines).

To my recollection, when I installed the gravity recirc the first time, some of my return lines had some drops in the pipe, but generally always sloped downwards. Can the return line ever have a counter slope if it is not particularly steep nor long?

In 2025, what is the prevailing approach/thoughts to this problem? How do you make a pump operated recirc work as efficiently as gravity feed? I do not want a pump that runs 24/7. And using a timer to shut it down overnight implies no hot water if you wake up at 4am.

Thanks for any suggestions or insights!

Eric

 

[Breplum]

consider: https://smartrecirculationcontrol.c...ZNlW_BRoEqPaf1CNA-R4bQ88NbR3jWPj3cSDxtuV5ICcJ
or have gravity but add Taco SmartPlug https://www.supplyhouse.com/Taco-SP...Km2uvMjKDiQYT_YPbxKvMBn7S27G9Z45gfrLTRbvI7HYI
Our favorite is from ACT but they have gotten very expensive https://gothotwater.com/

 

[Sponsor]

 

[Benze]

consider: https://smartrecirculationcontrol.c...ZNlW_BRoEqPaf1CNA-R4bQ88NbR3jWPj3cSDxtuV5ICcJ
or have gravity but add Taco SmartPlug https://www.supplyhouse.com/Taco-SP...Km2uvMjKDiQYT_YPbxKvMBn7S27G9Z45gfrLTRbvI7HYI
Our favorite is from ACT but they have gotten very expensive https://gothotwater.com/

All three options are pump-related. Having the Taco plug is to control a pump.

I'm trying to see if gravity in 2025 is still worth it given all these new options that are available for a pump system. I had no idea that there were so many automated/smart controls. I like the idea of the Taco plug to try and guess when you need hot water. I question how accurate it is though.

I also wonder about the smartrecirculationcontrol idea. Is a pump able to circulate water that much more quickly than just leaving the tap on? Or is the idea to make a HW demand (turn on & off the tap) then do something else while you wait for the pump to circulated? Advantage being that you aren't pouring tepid water down the drain, but effectively. you are still wiaitng the same amount of time for the HW to present itself than had you just turned the tap on and waited?

Thanks!

Eric

 

[Breplum]

IMO the best solution is the ACT brand motion activated with wireless but, of course, cost is very high.

 

[Jeff H Young]

Ive never ran a gravity circ system I heard they were no longer code compliant

 

[John Gayewski]

I use gravity but i know how to do it. Technically it's not legal. The main problem with gravity is it doesn't work worth a complex layout amd you might need larger lines. Why not try for gravity with the option to add a pump.

 

[Jeff H Young]

I use gravity but i know how to do it. Technically it's not legal. The main problem with gravity is it doesn't work worth a complex layout amd you might need larger lines. Why not try for gravity with the option to add a pump.

definately i like the simplicity and if someone has proper knowledge sounds good