Point of Use Hot Water Heater Questions

[Brian Elfert]

I have read stories of people who had their cost to heat water skyrocket when they put in a recirculating pump. The pipes will tend to radiate some of the heat from the water as it circulates so the water heater has to heat more often. A common thing is to put a timer on the pump to run only during times of day when hot water is commonly used. I don't know how common it is to have bills increase when recirculation is added.

[Bill George]

I have read stories of people who had their cost to heat water skyrocket when they put in a recirculating pump. The pipes will tend to radiate some of the heat from the water as it circulates so the water heater has to heat more often. A common thing is to put a timer on the pump to run only during times of day when hot water is commonly used. I don't know how common it is to have bills increase when recirculation is added.

Not if you do the correct way, Insulate the pipes.

[Jerome Stanek]

My wife could not get the concept of a on demand water heater she thought that it would give her hot water right away at the faucet. I had to explain it to her that it would just be like what we have without a tank. She wanted instant hot water so I got the ciculating pump and put in a return line.

[Alex Zeller]

Adding a return line in a two story house with insulation probably is not an easy option in an existing house. When I built my house I purposely made a chase that I can access from each floor for both water and electrical. I plumbed a pump on the domestic hot water line with a return line set up on a timer. It's connected to a towel heater and I have it set up on a timer so it'll come on a little before the wife was ready to take a shower. It also provided hot water much quicker to the shower and faucets in the master bath. The towel heater also heats up the bathroom as well (plus it has radiant heat in the floors).

[Dave Sabo]

I've been using one, like the one I linked to, for 10 years, no issues what so ever.
The claim about hot water on the cold side is a bit overblown IMO.
Yes you do get lukewarm water for a bit on the cold side but the entire point of the product is to get hot water to that point. If you want ice cold water in the bath, you may need another solution.

You’re missing the point entirely.

That lukewarm water stays in your cold water line until it’s expelled. The pumps don’t get tied in at a tub or a shower, they’re at a faucet. And not everyone likes or will tolerate warm water for brushing their teeth or filling a cup to drink. Depending on the particular setup that lukewarm water could last several minutes.

So, you’re trading fast / instant hot water access for longer wait time for cold water and the wasting of the water down the drain while you are wait8mg on that cold water to arrive.

Not if you do the correct way, Insulate the pipes.

Sure , but how practical is that when those pipes are inside finished walls , ceilings and stairwells ?

Answer: Not at all.

[roger wiegand]

Not if you do the correct way, Insulate the pipes.

Tearing walls and finished ceilings open to insulate the pipes gets pretty expensive pretty fast. I'd tolerate the wait for hot water before taking that on.

[Bill George]

Tearing walls and finished ceilings open to insulate the pipes gets pretty expensive pretty fast. I'd tolerate the wait for hot water before taking that on.

Well the OP has been given the only two choices I know of to fix his problem, maybe there are others but its either one of those or live with it. BTW you don't need to "tear apart walls" bore a hole and pump the space full of Insulation, exposed just add the pipe insulation.

[Edward Weber]

You’re missing the point entirely.

That lukewarm water stays in your cold water line until it’s expelled. The pumps don’t get tied in at a tub or a shower, they’re at a faucet. And not everyone likes or will tolerate warm water for brushing their teeth or filling a cup to drink. Depending on the particular setup that lukewarm water could last several minutes.

So, you’re trading fast / instant hot water access for longer wait time for cold water and the wasting of the water down the drain while you are wait8mg on that cold water to arrive.





Sure , but how practical is that when those pipes are inside finished walls , ceilings and stairwells ?

Answer: Not at all.

With respect, I'm not missing the point, I own one and I'm perfectly happy with it.
I offered it up as an easy solution to the OP's issue.
I also stated it might not be right for him.

[Dave Sabo]

Well the OP has been given the only two choices I know of to fix his problem, maybe there are others but its either one of those or live with it. BTW you don't need to "tear apart walls" bore a hole and pump the space full of Insulation, exposed just add the pipe insulation.

that's only slightly more practical. But still not a truly viable option.

And you just call around to a couple if insulators and ask them how excited about that type of project they are, and let us know. Then ask the spouse how receptive they are to repainting all the rooms that the patches went into. Most likely it's the entire house. If they're OK with that, call around to the drywallers (or plasterers) and ask them about taking on that type of patching job and get back to us. If you find one, be sure to check in person examples of their work and tell us if you found it acceptable.

With respect, I'm not missing the point, I own one and I'm perfectly happy with it.
I offered it up as an easy solution to the OP's issue.
I also stated it might not be right for him.

You're perfectly happy with it and mentioned the bathtub, but you totally ignored the drawback of warm water at the faucet where many people actually like cold water, and where the circ valve would be loated. It'd be kinda obvious that one wouldn't need any type of solution if they liked cold water for their shower or tub.

Hence, me saying you missed the point of warm water in the cold line not being overblown.

[Bill George]

that's only slightly more practical. But still not a truly viable option.

And you just call around to a couple if insulators and ask them how excited about that type of project they are, and let us know. Then ask the spouse how receptive they are to repainting all the rooms that the patches went into. Most likely it's the entire house. If they're OK with that, call around to the drywallers (or plasterers) and ask them about taking on that type of patching job and get back to us. If you find one, be sure to check in person examples of their work and tell us if you found it acceptable.

Really? That would be a DIY job in this house. How many wall pipe chases do you have in your house, I have three and spray can foam would be one solution. The rest are exposed in the basement. So what would You do to Solve the OPs problem? PS they have spray foam in 20 lb cylinders.

[Edward Weber]

that's only slightly more practical. But still not a truly viable option.

And you just call around to a couple if insulators and ask them how excited about that type of project they are, and let us know. Then ask the spouse how receptive they are to repainting all the rooms that the patches went into. Most likely it's the entire house. If they're OK with that, call around to the drywallers (or plasterers) and ask them about taking on that type of patching job and get back to us. If you find one, be sure to check in person examples of their work and tell us if you found it acceptable.




You're perfectly happy with it and mentioned the bathtub, but you totally ignored the drawback of warm water at the faucet where many people actually like cold water, and where the circ valve would be loated. It'd be kinda obvious that one wouldn't need any type of solution if they liked cold water for their shower or tub.

Hence, me saying you missed the point of warm water in the cold line not being overblown.

What I said
From earlier post;
"I've been using one, like the one I linked to, for 10 years, no issues what so ever.
The claim about hot water on the cold side is a bit overblown IMO.
Yes you do get lukewarm water for a bit on the cold side but the entire point of the product is to get hot water to that point. If you want ice cold water in the bath, you may need another solution. "

Bath, is short for bathroom, just like master, is short for master bedroom.

Let it go

[Dave Sabo]

What I said
From earlier post;
"I've been using one, like the one I linked to, for 10 years, no issues what so ever.
The claim about hot water on the cold side is a bit overblown IMO.
Yes you do get lukewarm water for a bit on the cold side but the entire point of the product is to get hot water to that point. If you want ice cold water in the bath, you may need another solution. "

Bath, is short for bathroom, just like master, is short for master bedroom.

Let it go

Repeating yourself (or having one) doesn't make it any more true.

The cold water wait time IS a decision point that many people will not find "overblown". For you it may be - for others , not so much. Sure, the point of a recirc. pump is to have instant or faster hot water delivery throughout the house, but there are tradeoffs of using that or using that over another method.

Is the cost of such a system "overblown"?

What about the added energy and water usage ?

Really depends on your perspective and what you find important, but all of those things go into a decision at the end of the day.


Our homes would be full neat-o , gee wiz, super cool gizmos / tech / features / higher quality materials materials, features, and conveniences except for those pesky details that are "overblown" according to some people.

[Bill George]

Running Hot side water to make it hot for your use, your paying to heat that wasted water. Cold water side, just paying for the water. I would run a PEX line back to the Water Heater and then insulate both lines as I described above.

[Jerome Stanek]

Repeating yourself (or having one) doesn't make it any more true.

The cold water wait time IS a decision point that many people will not find "overblown". For you it may be - for others , not so much. Sure, the point of a recirc. pump is to have instant or faster hot water delivery throughout the house, but there are tradeoffs of using that or using that over another method.

Is the cost of such a system "overblown"?

What about the added energy and water usage ?

Really depends on your perspective and what you find important, but all of those things go into a decision at the end of the day.


Our homes would be full neat-o , gee wiz, super cool gizmos / tech / features / higher quality materials materials, features, and conveniences except for those pesky details that are "overblown" according to some people.

The water usage is a lot less and the energy usage is almost the same.

[Alan Lightstone]

We installed a POU heater for our kitchen sink as the run was way too long from our tankless system, and it took a long time to get hot water there. It works very well, no issues. By the time that tank has exhausted its hot water, the tankless hot water reaches there.

Of course, that doesn't help our master bathroom or the den bathroom that are farther away and 30 feet up, but we couldn't run circulating pipe for that.