The usual method for installing a recirculating pump is to have a second pipe running from the hot water heater to the farthest point of the hot water line. The return pipe feeds into the cold-water input of the hot water heater. The idea is that the pump keeps hot water in the hot water line. So that the pump isn't constantly running, it's usually setup so that it only pumps when the water cools to a particular level and shuts back down once hot water has been recirculated. The setup usually also includes check valves so that cold water doesn't flow backward through the return pipe. When a recirculating pump is used, may plumbing codes REQUIRE the pipe to be insulated to conserve energy.

What about the sort of pumps that do not require a return line? Do they work as well?

I had one and thought it was noisy. Switched to a return line with a circulating pump with a builtin timer. Love it.

The ones that don't have the return line cause you to wait a long time for cold water and it took a long time to get the water temp adjusted just right. Lots of wasted water which I wanted to avoid. City water costs and the price never goes down.

kachinee,

The problem is not your water heater. The problem is bad design (bath at one end of the house and heater at the other).

Although a recirculating pump will solve the symptoms, they waste a lot of energy with the heat loss from the pipes.

The very first thing you should do is try to reduce the heat loss.

Start by determining if the hot water line is oversized. For example: If the line is 3/4" and you only need 1/2" you will have to run much more water through the line before it heats up. With low volume shower heads, faucets and appliances -- this can be a problem. I reduced the size of the hot water line to my kitchen for this very reason. If you downsize, consider CPVC or PEX for the run -- they don't conduct heat to the surrounding area like copper. They also have less thermal mass than copper or iron.

The second thing to do is to insulate the pipe. Pipe insulation is cheap and easy to install with the split self-adhesive foam. Miter the insulation at elbows and otherwise do a good job. You will need for the pipe to be insulated anyway if you install a circulating pump.

If these things don't resolve the problem, consider the pump. In most cases, however, running the water for a few seconds is cheaper than wasting all of that heat to standby losses in the pipes -- not to mention getting rid of that heat with the a/c in the summer.

If it is a tub/shower combination, run the tub for a few seconds -- it has a flow rate twice that of the shower.

This problem of the master bath taking a long time to get hot water is a common problem -- but is is mostly about bad design and builders and plumbers should do a better job of addressing it. In one case on this board, the hot water line to the master bath was in concrete with no insulation-- there was no heat left by the time the water got to the shower in the winter.

Retrofit recirculating pumps were discussed in this thread...

click here for link

Mine is still working perfectly and there is still no noticable elctrical cost but water bill savings continue.

Our Laing Autocirc has paid for itself many times over.

Lurker:

As you know, the issue is not the electrical usage of the pump but the standby heat loss of the pipes.

I am sure you are happy with yours -- It's also good to know that there is a unit out there that works well without a dedicated return line.

Nonetheless, I think that putting a circ pump on should be the last resort and should only be done in conjunction with pipe insulation.

I do respect the wasted water argument and in some locations, the water costs outway the energy costs.

Lake2007,

If you followed the link to the other thread I clearly said "If I was building a house or could easily add a dedicated return line I would prefer that, but all in all the Autocirc one-piece works. It is less complicated than the competing add-in two-piece Grundfos and now Laing has a pump that goes at the water heater with a remote manifold at the farthest sink like the Grunfos".

In a situation where adding a dedicated return would be at least very difficult and expensive if at all possible this type retrofit is a solution that gets you hot water now and saves LOTS of water and seems to cost so little to run that pump, and it only runs about once an hour for about two minutes, it doesn't impact my electric bill.

As I said, my LP costs (LP WH)are practically the same month for month as before the recirc pump, my elecric bills are about the same, but I'm saving at least $100 a year on my water bill. I see no down side to that.

kachinee

Check out this link http://www.lainginc.com/.

If you click on Recirc Pumps, there is a document on how they work. I also bought mine at www.HVACquick.com/Laing and they have documents on their site for how to hook them up with various configs.

The issue is not the tank - it is the plumbing pipes. There is a lot of water sitting in the feeder lines and it can take minutes for the hot water to push the cold water out of the way.

I had a similar problem but I have tankess water generators. We put the tankless units under the master suite (yes finally - hot showers instantly) BUT the kitchen, utility room sink, butler pantry sink AND the feed to the second floor all run to the other side of the house 88 feet away! The first time I put ther hot water on in the kitchen sink it took 5 minutes for hot water to flow. DW said "unaccepatble" and so began my first project on the new home - and we hadn't even moved in yet!

I ran a 1/2 inch return loop from my hot water genertators all the way to the other side of the house, and teed in just prior to where all the braches go. I insulated the main feeder and the return loop, used a 4 gallon hot water tank, and the Laing pump. It now takes 10 to 15 seconds to get hot water instead of 5 minutes - DW is happy.

If you use Laing - make sure you get the pump that has the check valve integrated into the pump assembly. That will reduce the number of parts you need. ALso - the smallest Laing pump is rated for I think a 250 foot total loop, so you have to pick the right size pump for the loop design you have.

Good Luck!

ps - I do not work for Laing. I am just a Joe Blow homeowner who saved his bacon when the DW turned on the hot water faucet and COLD came out.

Our master bedroom is about 40 ft from the water heater - DW would turn the hot water on and then leave it on for a long time while she did other things. The daily waste of hot water caused me to look for a solution.

I went to ebay and searched for circulator pumps - someone there offers the basic guts of taco's d'mand system http://www.taco-hvac.com/uploads/FileLibrary/102-140.pdf . Most sales of these pumps go for under $100 including shipping. Just search on ebay for "taco pump" and look at the blue ones.

I got one and installed it in our MBR - the pump already has undersink plumbing and a thermister w/controls for automatically stopping when there is hot water at the pump - I just added a doorbell, a couple hoses and 3/8" tees and now have hot water at the sink in about 2 minutes. It makes a quiet hum when the pump is operating. DW and I are very pleased with this circulator!

John

PS I am just another retired engineer/homeowner - I don't sell anything and have no connections to any suppliers - I'm just delighted to have found this solution to quick hot water at the sink without water waste.

Here is a link that might be useful: taco d'mand system

I am trying to decide between a hot water recirculating pump and the Hot Water Lobster. Does anyone know if the Lobster system will work if my hot water heater is in the attic? I have a two story house about 3,700 sq. ft. I have two 50 gallon water heater tanks in the attic. I takes about 4 min. to get hot water to the kitchen because it is so far away from the water heaters. The kitchen is on the opposite side of the house and of course on the first floor. There is also about a 4 min. wait to get hot water in an upstairs bathroom that is right above the kitchen. There are 3 other bathrooms and a laundry room on the other side of the house that get hot water in about 30 - 40 sec. I need to know if the Lobster system will have enough pressure to work because I have very long pipe runs about 80 to 90 feet to the kitchen. The plumbing in my home was very poorly designed. There is no way to move one of the water heaters. Also I am in Texas and here they don't insulate the pipes because they don't freeze.

Tam,

Check out this product, link below-

It is actually made by Grundfos (excellent) but this one is readily available and locally to the consumer, at a very fair price.

This will work fantastic for you! (live in houston and have one myself (grundfos)

Here is a link that might be useful: HD Hot Water Recirc

Hot Water Lobster comment update:
(in response to other questions and comments)

The Hot Water Lobster will work if your hot water heater is in the attic. The system works on thermal convection within the tank to circulate the hot water so it will work regardless of where your water heater is located. Just locate the Hot Water Lobster at the faucet farthest from your hot water heater or heaters for instant hot water throughout the home. If there are 2 extreme locations at opposite ends of a large house that take a long time for hot water, it would be beneficial to install a unit at each end. The Hot Water Lobster Instant Hot Water Valve does not continuously circulate. The valve automatically opens and closes when water temperatures reach your desired thermostat setting! No timer is necessary! The system will circulate hot water more or less based on your water usage. Tankless heaters take even longer than a traditional hot water tank to get you hot water! If you must switch a circulating pump on before your shower you still must wait for the water to get there! The Hot Water Lobster gives you instant hot water from your water heater! Check out the website for more info.

www.hotwaterlobster.com

Here is a link that might be useful: www.hotwaterlobster.com

This is not a retrofit answer but when we built our new home, Our master bath was at the end of the line. We had a recirc system installed and added timer switches in each bathroom, Laundry as well as the kitchen. In the kitchen we also installed a regular On-Off switch to the pump. When someone goes to do the laundry or take a shower, we turn on the pump timer for 3 or 4 minutes to get the water to the shower. The timer switch shuts off in a few minutes so the pump does not run too long but it runs long enough to fill the pipes with hot water throughout the house. If we are having guests over or expect to use the hot water more frequently, we turn the pump on from the kitchen On-Off switch so the pump runs all the time.

This configuration saves water, saves heat loss, saves electric ( to run the pump all the time ) and keeps hot water at the demand faucet when we need it. The only thing you have to do is remember to turn the timer on a few minutes before you get in the shower.

I was happy to find an easy device to take care of my various activities.
I was in search for various sources to find a suitable product. I had an opportunity to purchase an instant hot water valve "Hot Water Lobster and got it installed in my bathroom. It was really easy to install as I read the guidelines.
It is helpful for my family to get instant hot water in the morning. Compared to other devices, it is quite simple and easy to operate.

We used to face lots of problems as it was very difficult to get hot water in time. We had to wait for a long time. For detailed information, you may visit "Hot Water Lobster Instant Hot Water Valve site,www.hotwaterlobster.com happily, You can have a 30-day unconditional money back guarantee, as well as a 10-year parts and labor warranty

I was in search for various brands. However, I have found it to be very useful. I had purchase the device 2 months back and it�s working well. So, I am able to save water considerably. Additionally, I can get instant water supply. My time also saved in the morning.

If you would like to know more information, you can browse through the website: www.hotwaterlobster.com .

i like to get some technical information about the hot water circulation time to reach the remote fixture from the calorifier.my calorifier outlet temperature is 70-Deg.I want to calculate the time required reach this 70 deg hot water through insulated PB pipe to reach remote fixture at the time of Anti Legionella cycle .circulation pump is using for the circulation of hotwater

My plumber said the Lobster will cause your cold water to now run lukewarm. Has anyone (besides a Lobster salesman) used one of these in a Southern/Western state? In Texas, cold water is almost always lukewarm except in the dead of winter; I don't want to create another problem by trying to fix one!