Get Hot Water Faster and Lower Water Utility Bills with a Recirculation System

Comfort System 1

Photo courtesy of Grundfos

As a daughter of parents who lived through the Great Depression, I was raised with constant reminders to “Turn off the lights,” “Shut off the water,” and “Put on a sweater if you’re cold” instead of ramping up the furnace. The concepts of energy efficiency and “being green” are not really new to most baby boomers like me. My husband and I do what we can to protect our environment and natural resources, not just because it’s the right thing to do, but because it helps our budget. It’s ingrained in us.


Until last year, however, our green-ness was pretty much limited to things that most people do these days. We recycle our paper, plastics and glass; we have reusable grocery bags and water bottles; we have a setback thermostat, timers for outdoor lighting, a fuel efficient car and high efficiency appliances . . . All of these things add up, but I knew we could do more. In fact I was reminded of it every morning I’d turn on the shower and waste several gallons of water while waiting for the temperature to be “just right” before stepping in. Our master bathroom is the furthest room in the house from our water heater. Some mornings, it took three-four minutes before hot water finally made its way to this room.

Last year, we purchased a hot water recirculation system with the hope of saving water and money on our utility bill. The “driver” of this system is a low energy pump, about the size of a softball, which was installed near the water heater in the basement of our nine-year-old home. The pump was plumbed into the existing hot water supply line to circulate hot water throughout the house. On the main level, a small bypass valve with a temperature sensor was installed under the sinks in our master bathroom and kitchen. These strategic locations, on opposite routes of the water supply lines in our home, ensure hot water is available wherever we need it—not just in the kitchen or master bath, but in the powder room, laundry room and guest bathroom. The circulator pump circulates water to the bypass valve, which connects the hot and cold water supply lines. The valve stays open until the water reaches 95 degrees at which time the bypass valve closes and hot water is ready for use. Last but not least, the circulator pump has a built-in timer that operates the unit only during times of the day when hot water typically is used.

Hot water recirculation systems can be purchased at home and plumbing supply stores as well as through local plumbing contractors. Andy, our plumber, was familiar with such systems and quite enthusiastic about them. Within an hour, our hot water recirculation system was in place, and Andy’s last words to me as he left were, “You’re going to love it!” I laughed. How can you love a pump?

Faster Hot Water – With Less Waste!
Well, one year later, I have to say with a straight face, I DO love this pump! Besides feeling very good about not wasting all that water in the shower anymore, it’s so gratifying to have “instant” hot water from any faucet in the house, any time we need it – for cooking, cleaning, washing your hands and face, shaving . . . In fact, whenever I’m away from home and have to wait for hot water, I realize just how much this little pump has spoiled me in terms of comfort and convenience.

My husband and I are empty nesters. We no longer use near the amount of water we did when we were raising our children. But between the two of us, our water utility bills indicate a reduction of more than 20 gallons of water per day in the year since we installed our hot water recirculation system. For two people who take relatively quick showers, that’s over 7,000 gallons annually! Imagine the cost implications if larger families, more homes and buildings used hot water recirculation systems. Imagine the savings to one of the world’s most valuable resources.

There are a multitude of things people can do to be green these days, but some of them cost a lot of money and are inconvenient and impractical. The hot water recirculation system we have wasn’t the least expensive of such systems, it cost around $600, but it was affordable, and every month, we get a return on our purchase with the savings on our water bill. Every day, when we turn our faucets to “H,” we get another return in terms of comfort and convenience. Sometimes, being green is more than being good to our planet. It’s being good to us.

Kathy Teach is a homeowner in Lenexa, Kansas.

28 Responses »

  1. When my husband and I lived in Arizona we had something similar, only it was activated by a little button instead of a timer (we had a button in the kitchen and in both bathrooms). If we wanted hot water we just pressed the button, which activated the recirculating pump, waited 30 seconds, and then opened the hot water tap to get hot water.

    • I keep a bucket in my shower. When I turn on the tap, the cold water runs into the bucket. When it starts to get warm, I remove it and get in. During the summers, that water is used for my plants . In the winter, we use it to flush the toilets. This is a practical, easy way to use this water instead of wasting it.

  2. Do you have any information on the increase in electricty costs? Thanks.

    • Loretta

      The amount of electricity used by these systems is in the few dollars a month range. However the cost of heating the water rises significantly. When the pipes stay hot they lose energy which means more hot water needs to be sent out.

      Another solution is to activate the pump by turning on and off any hot water faucet in the house, wait 10 seconds and get hot water without wasting water or energy.

  3. Unfortunately, although you are saving a bit of water by not having to run water down the drain while you wait for the hot water to come, you are using a significant amount of energy running a pump CONTINUALLY while the timer is on. This pump runs whether you are home or not and whether someone is using water a the time or not. I think that if you run the numbers on the cost of the added power draw you are actually wasting way more than you wold by running water down the sink (mainly because water is so cheap, another problem with our energy system).

    You would be MUCH better of with a demand type system where you push a button when you need hot water which then starts the re-circ pump, which runs only until hot water reaches the fixture that you are using.

  4. - Add me to the list of people who only sees increased energy consumption .

    I would ask the manufacturer for their data as a start , If there was ANY SAVINGS , this would fall under the catagory of an ” Energy Star ” device -

    Also , I would worry about untrained installers

    • This article is focused on the water savings, not the electrical. In fact, nowhere is the energy savings of such a system even mentioned in the article. It is an add-on, so it stands to reason that you are going to probably use a little more energy. I suspect it is fairly minimal depending on how the system is controlled. But it is the WATER savings that is the compelling benefit here, and that IS significant.

      Homeowners should ALWAYS worry about untrained (or incompetent installers). Unfortunately.

      • This article is good, but no technical data to show the “low energy pump” electrical needs-on a daily, monthly or yearly cycle.
        At least, they do mention—The “driver” of this system is a low energy pump, about the size of a softball, which was installed near the water heater in the basement of our nine-year-old home.

        As a user of Hot Water on Demand in CA and using this system in Europe (by the way, Europe has been using this type of system for years) it is the best choice. Only in the past 8 years in the US has this system been marketed as “Green”

        1. a traditional hot water heater is an energy hog-it constantly heats a specific amount of water-all day-all night,

        2. depending on the hot water heater and it’s location, it can waste many gallons of water, before reaching the tap and the user

        3. This hot water circulation pump may help save some money and energy use, but a smarter-long term investment would be Hot Water on Demand.

  5. Hot Water Recirculation Systems and Energy

    The concerns about energy use are valid. The amount and cost of electricity used is a wide variable depending on local energy costs, and the length of time the pump is programmed to operate. While user activated systems are available, they are dependent on the homeowner action of activating the system. Programmed, or timed systems activate the pump when the homeowner is most likely to use hot water based on the users schedule and habits. In traditional/return line systems, the pump has an internal sensor that turns the pump off when the recirculated water returns hot. Typically, the pump is programmed to activate only 2-3 hours per day.

    Energy comsumption for pumps of this class and size range in the 25-50W range, or less than an average light bulb. There is very little energy loss from heated water transported through plumbing piping.

    The intent of these products is to reduce water comsumption (waste). A typical household can waste 12,000-15,000 gallons of water annually waiting for hot water. To truly assess the energy question, you must consider the latent energy consumption needed to transport that water from its source to a water treatment facility, transport again to the home, remove the waste water from the home, transport it to a waste treatment facility and treat it again.

    This process of transporting and treating water uses a considerable amount of energy. Cost may vary from system to system, however, this process uses considerable more energy than the operation of the pump used in a hot water recirculation system.

    When all things are considered, a hot water recircualtion system saves water and energy.

  6. Just a note on the electrical energy use! A large portion of the electrical energy used by the pump turns into heat as it circulates the water through the pipe. With ECM circulator pumps used by the major circulator manufacturers, that portion (the pump efficiency) is even higher. The heat energy introduced into the domestic water by the pump is a direct subtraction from the heat energy that would have been required by the water heater. VERY EFFICIENT METHOD OF REDUCING WATER USAGE!

    • Thanks, David!

      Folks, you are in luck. I have known Mr. David Pleasants for YEARS and he is a total mechanical nerd — and I mean that in a GOOD way! ;o) Rarely to I accept anyone’s word at face value, but David’s I do! He has been teaching mechanical engineers about pumping systems for decades!

      Thanks for the info about energy consumption of these little pumps, David. I’m sure few people would think to factor in the transfer of heat from the pumps to the water to this overall equation!

  7. This is so interesting to see this conversation. Just yesterday morning, I contemplated the big waste of water I was committing as I brushed my teeth. Then I began wondering how much water is being wasted as a result of millions of people every morning and night brushing their teeth while keeping the water running. I vow to get a container for my water and rinse my mouth as necessary while brushing from this day forward. Next, I’ll work on the unnecessary toilet flushings!

  8. In my house, you probably wait a minute at most for hot water. I have just taken to putting a bucket in the shower so I get a gallon or so of cool water for flushing, watering plants, whatever. Today I dumped it on my compost pile because it was too dry, and decomposition needs moisture.

    Low tech works too!

  9. Hi All,

    OK, I am still being “reminded” (saying it politely) that I should have done more research before I replaced our hot water tank for a whole house tankless unit. The tankless unit works great once the hot water gets there but since there is no more residual heat sitting in the pipes any longer, it takes even longer to get hot water than before.

    Putting heat wrap around the copper pipes helped some (less of a radiator cooling effect and copper conducts heat very well) but it’s not enough. Also had to disconnect the [brand name withheld] humidifier water supply from the hot water line because the flow was not enough turn the heater on so all I was doing was drawing more cold water into the pipes before the humidifier line hook up – quite a distance from the heater.

    Going back to the drawing board I found this on-demand fast re-circulation pump that I heard was good [brand name withheld] but am asking for advise if this product is really good, is there a better product out there. . .

    I’d be too embarrassed to make another mistake this time around.

    Thanks and have a blessed day.

    • PEndrasik,

      Brand name is important in your case…

      I am a plumber and I would consider myself well versed in domestic water systems and designs. That being said;

      Your tankless heater is designed to only activate when water flows through the heater, your issue is not really related to residual water within the pipes, but the design of the tankless water heater in itself. A tankless water heater has what we call “electronic ignition”, when the faucet is turned on the heater goes into a prepurge mode, clears any unwanted gases from the combustion chamber, opens the gas valve, ignites the flame and quickly tries to get the water that is flowing through it up to temperature. This process can take several seconds. The water then needs to flow from the location of the water heater to the fixture you are wanting hot water from, which adds sometimes minutes to the wait.

      Tankless water heaters pose several problems with recirculating systems, which are:

      Most (not all) tankless manufacturers do not want you to circulate hot water through the tankless water heater, they also sometimes void the warranty if you do so.
      Tankless water heaters incorporate several sensors to regulate the outlet temperature of the water, recirculating systems can play tricks on these systems.
      Heat exchangers within tankless water heaters can build up a lot of calcification when used with recirculating systems, the calcification leads to corrosion and costly maintenance and / or replacement.
      Tankless heaters use far more energy than a standard water heater, but in short bursts in order to heat water as it passes through, adding a standard recirculating system to a tankless water heater can bring its efficiency down several factors and even defeat the purpose of installing a recirc and / or a tankless water heater in the first place.
      Tankless water heaters are activated by flow of water, some recirculating pumps do not flow enough water through the tankless water heater to activate the flow switch.

      There are some ways you can achieve faster hot water with a tankless water heater;

      Centralize the tankless water heater to the most commonly used fixtures within the residence in order to cut the amount of piping between the water heater and fixture.
      Install a system that is designed to work with tankless water heaters, metlund makes a pump that can be activated with either a button or a motion sensor, we have had good success with these systems and tankless water heaters, they also do not void the warranty of most tankless water heaters.
      Install an electric buffer tank with a traditional recirculating system. This type of system is great for comfort and convenience. It provides other improvements to the system as well. And you keep the efficiency of the tankless water heater. A buffer system can prove to be more costly up front and in most cases considered a luxury improvement.

      I hope that helps!

  10. Good points.

    There is also small heat (tankless) units that go under the sinks in bathrooms or utility rooms that have the hot water there, used in large or long home-runs from the hotwater tanks that are more then 40 feet away!

    Your idea could be cheaper?

    I’ll check it and send some feedback!


  11. A second note here.

    Replumb for waste water from sinks, showers and washers to cistern’s to water gardens and lawn, or to recirculate to filters and can be reused!

  12. My wife and I had the exact same device installed in our new home back in 2005. A few years later, in a meeting with a group of semi-educated/politically active “green folks”, I was thrown under the bus for wasting the energy to run the pump. Frankly, having devoted my business to finding financial solutions to fund residential energy improvements, I felt bad and a little ignorant. At the time that we built our home, we had two teenagers living with us and the entire purpose of installing the pump was to reduce our water consumption. I’m glad to see that someone smarter that me, who has actually measured the difference in wasted water has proven that our investment in this system is producing the environmental benefit that we had hoped. Great comments from the group!!

  13. The product is outstanding and does exactly what it is advertised to do. From a “Green” standpoint it is very green as water is a resource that is going to get very expensive in our lifetime. The more we save and conserve now the better we all will be. People think war about oil is silly, wait till we are at war over water. Water is by far our most precious resource and is wasted as much as it because we take it for granted. More water saving products are needed and this is a good one. Great post.

  14. I think it’s great that people are at the very least engaging in conversations about conservation and efficiency. The pump is a good idea but the energy cost is a downside. We have a direct connect plumbing manifold and an energy efficient tanked water heater. Each fixture is independently plumbed separately for hot and cold and has a corresponding shut off valve at the manifold. The longest these runs could be is about 25 ft. At that length the whole line holds only about 4 cups of water. Since moving in I have noticed it takes no time for the hot water to reach the shower. Also, it’s been great for maintenance, we had a leak from an improperly installed pot filler over the stove and were able to just shut that valve off instead of all the water. These systems are relatively easy to retrofit. Mike Holmes from Holmes on homes uses them too. I have had several clients have issues with their tankless systems. I just woder how we came up with the standard plumbing methods in the first place, is it just me or does it seem like it goes around its a$$ to get to its elbow when it comes to water delivery? Good work everyone in doing your best to go green and participating in the conversation! Knowing is half the battle!

    • Hailey,

      The system you have sounds like a manifold system, and while sometimes these systems prove to be more convenient for a problem as the one you described, they also lead to other problems and are other times very cost prohibitive;

      The cost to install a manifold system on the average household can be 50 to 75% more and leads to a lot of waste.

      Pex and other plastic piping is petroleum based (we are talking conservation)… The amount of materials to complete a system such as yours can drive the amount of materials needed above a typical domestic water system up sometimes as high as 150 to 200% more in piping and strapping materials.

      A good majority of jurisdictions within the United States actually require recirculating systems on any system that is further than 25 to 30 feet away from the hot water source, systems such as yours don’t accept recirculating systems, and there aren’t really any fixes available to make them accept recirc systems.

      More piping (individual runs to each fixture) leads to more joints as well as more potential for leaks. As time goes on, many find that the convenience factor sometimes doesn’t pay off due to the amount of piping within a household and the money required to maintain that piping.

      • Hi Pete,

        Perhaps you can shed some additional light on my issue. I completed a 10,000 sq ft house
        with 10 baths. The master bathroom’s shower and free-standing tub (2nd floor) take about 60 seconds to reach adequate temperature (good GPM I guess), but the two vanities take 3-4 minutes to reach 100 degrees. These sinks are about 120 feet away from tank, and are a separate line from the tub and shower. It’s a geo-thermal system with a propane powered hot water system.

        I also have issues with the kitchen sink (its floor) not heating up well, which is also a separate line.

        Does the Grundfos system make sense which is located at the heater and has manifolds that are placed below the problematic sinks?

        Will it work for such a large house?
        Will it turn the cold water lines warm?

        Thanks for your input

  15. Hello I am a plumbing and waste tech for las vegas valley water district, I myself notice a 45 sec delay for hot water in my home, but I had the option for a resirculating system when my house was built but because of my experience in the plumbing field I have seen pipes destroyed due to constant water flow on pipes causing them to wear premature. Mostly on homes plumbed in copper piping but even on newer homes with plastic piping. What the government doesn’t tell you 88% of water that goes down your drain is recycled and reintroduced into the potable water system in your city, the rest is black water containing feces and other waste, and the rest is lost due to a small amount of evaporation not much because when water is concealed in piping it can not evaporate. So save your money on the power from a constant resirc pump because trust me the timer always gets bypassed because in our day and age we all have different schedules and we never bath at the same exact times. Thanks for reading.

  16. I’ve done my share in researching hot water circulating pumps and found a number of viewpoints. With a background in energy management I tend to look at the mechanics of devices. Often, just reading the manufacturers website can give you a sense of whether their product truely targets being a green product or targets filling their pockets with green.

    During my searchs the most common problem was people having to wait for cold water after installing one of these systems. Heating water is not cheap and unless your pump runs all the time and uses more than a 60 watt light bulb it’s not going to be much of an impact. However, if your constantly introducing water into your water heater you will feel it come bill time. Make no mistake pumps use energy but not as much as a water heater does. It will take the water heater more energy to heat the water flushed out of your pipes then it takes to pump that same amount of water out of your pipes.

    • Scott,

      You have a great point, but;

      The energy used to reheat water a few degrees is very much offset with a recirculating system.

      A good example;

      Recirculated water comes back a few degrees cooler than when it left the water heater. The amount of energy needed to reheat that water is very little compared to;

      Scott waiting 30 to 60 seconds for hot water… You just removed gallons of hot water from the water heater, the temperature rise that is required to heat fresh cold water to desired temperature compared to recirculated water very much offsets the cost to run the pump, not to mention the gallons of water saved.

      Also, the more occupants in the residence as well as the more bathrooms, the higher the savings becomes.

  17. I’m just starting my “research” on the this, but your situation described here is almost identical to ours — “empty nest” baby boomers, house layout, etc. And I know about the savings on the water bill, but what about your electrical bill? We need to do something, but my husband is of the belief that there won’t really be much savings due to the increased electricity needed to maintain the water temperature in the pipes! By the way, we have a gas (propane) water heater, but could switch to an electric one as it probably will need to be replaced in a year or two. And there was a recirculating pump attached when we got the house (a foreclosure) but it had burned out for whatever reason.

  18. Planning on putting in recirculating system with timer for 2 hours per day. Lavatory in master bath is logical place for valve. Our.bed is only about 10 feet away from that lavatory, Is valve noisey? .Not worried about power cost, our power bill is only .90 cents per month with our panels, large our pool pump runs 8 hours per day and we have 4 refers. Tried solar hot water heaters a few years ago loved the hot water but replacing a tank cost $1,000 and had to do that two times in ten years.. Also had three turbo toilets that was a terrible experience.. I think I would like the recirc pump but plumber quotes 700 installed and electrician quoted 400 so I have to love it for that cost..Have you heard of those little valves failing ? That could be a disaster in our house. I would want to be sure and turn it off when we are away.on vacation.


  1. Get Hot Water Faster and Lower Water Utility Bills with a Recirculation System | Green Conduct

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