Does anybody here have a hot water recirculating pump?

John Pollman

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Location
Rochester Hills, MI
Hi all,

I live in a ranch and there's probably forty feet between my hot water tank and the main bathroom in the house. The kitchen is at least twenty feet away also. I'm getting tired of pouring water down the drain waiting for the water to get hot every time I want to take a shower, wash my hands, or do a dish in the kitchen sink. I'm pretty close to ordering a Grundfos hot water recirculating pump to hopefully save some money on all that wasted water. My water bills are getting ridiculous and I'd like to try to cut them back a bit. Not only for the money, but it's a huge WASTE of water to dump at least three gallons of water down the drain every time I need hot water. I can get the system for $239 and I can install it myself so it sounds like a pretty cost effective solution. Do any of you out there have a hot water recirculating pump? If so, how well to they work? As I said before I'm just about ready to pull the trigger and do it but thought I'd get some feedback if possible before I do.

Thanks in advance!

John
 
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what`s more energy efficient......running the water heater more or buying a couple gallons of water?.....those recirc. pumps are a good convience but as far as saving money?
 
Well the way I see it is that it will be well worth insulating my hot water line and installing the pump. I see it as a huge waste to dump that water down the drain. Water that even though it's cold, I've already paid to heat it and then let it cool down. I'd imagine the electricity used to run the pump will not be that expensive and it has a timer so it doesn't run all night. I'm sure that it adds up to thousands of gallons per year that don't need to be wasted. The way water costs have been going up, every little bit helps.

John
 
hot water

If it is time for the tank to go, you could look at the tankless systems. Renai makes one that is rated way up there. My heater will be going this spring and I am leaning towards that one.
 
Actually I just installed new high efficient power vented water heater two years ago. At the time I considered tankless but that's a huge difference in price. Besides, even with a tankless you still have the same problem. Once you shut the valve on the hot water line that water gets cold after a while and even if the water is coming from a tankless system, you'll still have to dump that water down the drain until it gets hot again.

John
 
I'm thinking along the lines of what Tod says: What's more cost effective, running the tap till hot comes out or running a pump that keeps your water heater running. You ARE pulling hot water away from a super-insulated tank and will most certainly lose some temperature there.

Ultimately, find the unit you want. Get the specs. Do the math over a year's time. Do the same with your water bill. But don't rule out the side-effects of both systems and do the math on those things, too (does having a pump keep the water heater going more? What's that cost?).

Also ...

I think you may find that your pipe run is 90% of what slows your "time to hot". If those pipes are full of cold water, buried in cold ground, you're probably spending most of the time heating that pipe up. You'll see water from the tank pretty quickly, maybe within a gallon (i'm guessing), but by the time it gets to your tap, it's frigid because the pipe was so cold. Certainly pumping hot water through it all the time will keep it warmer most of the time, but that means you'll be losing a significant amount of heat to the ground that pipe's buried in. Superinsulating your buried pipes might be more help than anything. I'm just guessing, but my mind's eye sees the pump as possibly being a wash.
 
I do have some more homework to do. But the pump doesn't keep hot water flowing through the pipe all the time. The pipes are in the basement running just below the floor joists so they will be easy to insulate. There is a valve system that mounts at the furthest faucet from the heater. (the main bathroom) It apparently has a temperature activated valve in it. When the water drops below 98 degrees, it opens and flushes some of the cooler water back into the cold water line and replenishes the water with hot. Yes, you may get a little bit of luke warm water out of the cold spigot when you turn it on but they say that water dissipates rather quickly. (much less time than running the faucet to get the water on the other side hot) The pump also has as timer on it that you set to operate for only the times when hot water use is at its peak. It may not be perfect, but I really see much less waste with a system like this. With what they're charging us now for water and sewer disposal it has to add up to at least some savings. The way I see it is that you're not necessarily making less hot water but you're "throwing away" much less water than without a system like this. Sure, you may have to recirculate and reheat some water but you're just reheating the same water not NEW water that would just go down the drain.

John
 
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John,
Something else to consider - a "point of use"/"under sink hot water heater". These have been used in situations like yours to give instant hot water, but allow the main tank to take over for the full job. They are more common in Europe and Asia as space savers and provide the only source of hot water (no main tank). Just a thought. You wouldn't be wasting a lot of water, and it wouldn't need to circulate.

FWIW,
Wes
 
I thought I seen a system on tv that you turn the pump on when you want the hot water at that sink and it recycles it until the hot water gets there shuts it's self off, then you turn on the faucet. Maybe I didnt understand how it worked but thats how I remember it anyway. Might of seen it on This old house or ask this old house.
Stacey
 
I had one of those hot water recirculating pumps in a home I lived in earlier. It was a real energy hog.

The best solution is to locate the hot water heater close to the place where you're going to use the hot water - note that most homes have their "wet" rooms located fairly close to each other. In additon to giving you faster hot water, it minimizes the cost of plumbing. If the bathrooms and the kitchen are separated quite a bit, the best solution is to install an additonal hot water heater and split the load.

Also consider if any of your wet rooms are not used very much. If so, locate the hot water heater so that room pays the penalty when hot water is used.

And look into the pressure sensing shower controls. They really work - someone can turn on a faucet or flush a toilet and you won't even notice it.

Mike
 
I've got a set up like Stacey describes, runs when you push the button - like when you start clearing the table, then they hot water is there when you start doing the washing. Ours has a wireless set up for the button so you can keep a remote in the dining room. The cold water in the hot water line is pumped back into the cold line until the water at the pump is hot. We've probably got a 40' run to the heater, takes about 30 seconds max to get hot water with the pump. Ultimately, the efficiency of the system depends on the house layout and where you place the pump.

I don't think these systems really waste a whole lot of energy - just what the pump takes running for 30 sec at a time. The balance of lost heat with the heater is the same as if you just run the water, or if its well designed, pumps lukewarm water back into the heater, thus saving you a little energy. It'd take years of saved water to pay for the pump though - but thats not the point.
 
John, here is a link to a system that wastes no water and recirculates the water back to the water heater. I don't know how the cost of the unit will compare to running the water down the drain until you have hot water at your basin. I suppose if water conservation is your goal it would be the thing that you are looking for. Also Lowe's has a similar system in their stores that you can get a first hand look at. I have considered installing one but I just have not made up my mind yet.
Check under search technology then look in hot water recirculating units
http://www.toolbase.org/TechInventory/Submit.aspx
Chuckhttp://www.toolbase.org/TechInventory/Submit.aspxhttp://www.toolbase.org/TechInventory/Submit.aspx
 
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