Hot Water Recirculation Pumps

[tmark]

To get instant hot water at the sink and shower, I am thinking of getting one of those hot water recirculation pumps installed either under the sink farthest from the hot water heater or installed atop the water heater.

Anyone have one of these units? What's your opinion on these units? The pro is you get instant hot water but the negative is you get a negative return on your investment.

I'd like to have your opinions on this matter.

[edpm3]

You pretty much summed it up. We have one mounted on the water heater and it worked well. It provided instant hot water in the bathroom at the far end of the house, which is just what my wife wanted when she was getting ready for work in the morning. Even though it had a timer that let us set the periods it would be active, it did increase the electric bill. Now that my wife is retired and is no longer on a strict schedule, we have turned it off. I can't speak to the type that heats the water at the point of use.

[togor]

Copper or PEX system? Affects the amount of heat loss you'll have with no water flow. Copper is a better heat conductor so higher losses, which make the water heater work a bit more to hold temperature.

[Duane Hansen]

The recirculating pump is a great way to go when you are building a new home but after the fact can be a bit tough. A return line would have to be installed from the farthest fixture back to the hwt. Also a couple of check valves need to be installed along with the brass impeller recirc pump. Grundfos and Taco make good pumps. If you are unable to install a recirc line then the under the sink units will work. This unit takes hot water from the stop under the sink and recircs it back to the hwt through the cold water piping. This can cause cross connections in the system at other fixtures.

[gpb]

Another possibility would be a tank-less demand heater located close to the usage point.

https://www.energy.gov/energysaver/water-heating/tankless-or-demand-type-water-heaters

[Vern Humphrey]

We had a system like that in each bathroom when we lived in Alexandria, Egypt in the mid-'50s. It was gas powered, and when you turned on the hot water and it would light up -- very impressively, too.

My grandmother came to stay with us a while and we forgot to warn her about it. The first time she went to take a bath, the thing lit off, KABLOOM! and she just about xxxx a brick!

[jaie5070]

I remember an episode of This Old House where they installed a small pump under the sink furthest from the water heater. It would pump from the hot line and into the cold line so you wouldn't waste water. There was a switch to operate it and it could be wired with a remote switch for an adjoining bathroom.

[phil441]

I asked one of those radio station call-in gurus about them and his only concern was that over a long period of time you would get more wear from particulates in your water at any sharp bends in the plumbing. I have no idea if he knows anything or not.

[tmark]

You all answered my question well. Thank you!

[Johnny P]

Friend restored a large old two story home, and it took forever to get hot water to the shower in the master bath. He had one of the instant hot water devices installed in the bathroom, but could never get it to work correctly for the shower. Finally figured out that the lavatory water had to be running at the same time to get the correct temperature hot water.

[jjrothWA]

The pump should be fixed at the point of farthest application and return to the inlet of the hot water tank and there MUST be added extra insulation on the lines.

The smae for a "unlimited water heater, in that a small hot water heater gives a reservoir to draw from the allow the "unlimited" to get up to temperature and flowing, then a thermostate allows the small water tank to shutdown. BUt insulation helps on all lines.