Return to the Plumbing Forum | Post a Follow-Up

 o
How long should wait hot water to get 30' from tank?

Posted by wynswrld98 (My Page) on
Fri, Apr 5, 13 at 16:46

I have an electric tank water heater in the garage that services the kitchen and a couple of other things in the house in the same general area. The house has a tankless gas water heater on the other end of the home that services the showers on that end of the home.

It's taking about 45 seconds to get hot water to the kitchen sink, the distance from the water heater to the kitchen sink is about 25-30' (ofcourse no knowing what path the water line is running since it's behind drywall).

What would anyone guess is a reasonable amount of time to get hot water to the kitchen sink based on this kind of setup?


Follow-Up Postings:

 o
RE: How long should wait hot water to get 30' from tank?

For your system, with your pipe size and your flow rate?

About 45 seconds.

If you are interested in the non-smartass answer:

You didn't provide your pipe size or the age of your faucet so I will make the following assumptions:
(1) Faucet was purchased after 1994
(2) Pipes are 3/4" copper
(3) You've got about 40' of pipe

Modern faucets have a max flow of 2.2 gpm. That amount of water travelling through 3/4" copper pipe travels at 1.46 ft/s. If the water traveled along in a perfect slug with no mixing, it would take a 27.4 seconds to exist your faucet, but it doesn't. Some mixing, and therefore cooling, takes place at the lead edge. In addition, the water is losing heat as it heats up the copper pipe along the way.

If your pipe is 1", 2.2 gpm would travel at 0.86 ft/s and take 47 seconds plus the extra time for heating the pipe and mixing with the cooler water.

Of course, YMMV if your faucet allows less flow, pipe diameter or length is different, etc,


 o
RE: How long should wait hot water to get 30' from tank?

Brand new faucet spec for it is 2.2 GPM, pipes are 3/4" copper.

So it sounds like what I'm experiencing is normal. It's funny because as you are at sink waiting to wash your hands or rinse dishes it feels like it takes forever to get hot water but timed it at 45 seconds.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Plumbing Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here