Hot water recirculating pump? Cost to operate? (floors, how much, foundation)

[goldenncmom]

Hi, we have one of those houses where the hot water heater (gas tank) is located in the garage, and the kitchen and master bath are on the opposite side of the house (with the master bath above the kitchen). It takes forever to get hot water to run out of the faucets in both areas. After a bit of research, I learned that it is possible to have a hot water recirculating pump installed to keep hot water in the lines at all times. I have some questions about the practicality of this device. We have a brand new water heater so we are not interested in tankless at all (and from what I have read it will not solve the waiting problem anyway).

1) Is the water recirculated back to the tank and dumped into the top? What I have read is that this can cause your gas bill to increase because the tank has to constantly reheat the recirculated colder water. Is this correct? Could this be resolved by putting the pump on a timer so that it is just circulating hot water through your pipes at the most desirable times? (In the morning for showers, and the evening for kitchen activities and dishwasher).
I am under the impression that these pumps save water instead of having the cold water run out of the faucet until it gets hot and go down the drain, is this correct?

2) I have also read that these devices run on electricity and can cause an increase in your electric bill. Again, is it possible to use a timer to minimize this?

3) Is anyone able to report on the actual performance of one of these pumps? Does it work well? How much has your electric/gas bill increased as a result?

4) What is the approximate cost to install?

Thanks!

[frankpc]

We have friends with a similar situation. They elected to go with a local "instant" hot water heater after looking at the option you described. Not sure how much analysis they did, but there's no free lunch either way unfortunately. While you would have the expense of the new unit, it does mitigate the other concerns you mention and it does not have any time of day issues to deal with.
Another issue is that most dishwashers require a certain inlet water temp to function properly as the internal temp boost is not designed to accept cool water. So if you use the time delay start on your dishwasher you could be compromising the cleaning/sanitizing. A good way to check this is to get hot water running in your sink and start the dishwasher immediately. If it cleans better in this scenario than when the water in the pipes is not hot (say using the time delay to start it after you go to bed) than you have a water inlet temp problem.

Frank

[James1202]

When you remodeled your bathrooms last year that would have been the time to consider making the hot water supply more efficient.

It sounds like your supply leads aren't insulated and they run through an uninsulated space or they're being cooled by A/C. Insulation is the first thing to check. If your supply leads are less than 30' then the water should be warm pretty quickly.

If it's greater than that then a small on-demand, a second water heater (under-counter), or moving your hot water tank to a more central location are the next options.

A recirculating system requires a loop for water to return to the heater. Chances are your plumbing doesn't have this already...water dead-ends at the farthest fixture. That's why a recirculating system is a last resort option. Also, many municipalities have restrictions on what can be done within a home plumbing system and you should check with your bldg. dept./water supplier.

Hot Water Recirculating Pumps

[MrRational]

Put an electric water heater NEAR where you actually use hot water.
A little one might be enough but a full sized one will for sure do it.

[ESPLUMBING]

This will solve your problem

Grundfos USA

[Donn2390]

I have a Hot Water Circulators Demand Recirculation System Record Efficient Similar to the one ESPLUMBING recommended, but much better.
It installs under the sink farthest from the W/H. It takes five minutes to install, if you really take your time. You will need a 110 outlet under the sink, but that's easy.
I don't have mine running all the time, so there is no excessive electric or gas bill. I have wireless switch in the bathroom which I turn on when I want to shower. You can put them on a timer to come on when you usually want hot water, i.e. couple of hours in the morning, couple in the evening, when you have a need for hot water. Lots of options as to how often you want it to be on.
It's expensive, around $400. but no more waiting for hot water.. I love mine..

[Donn2390]

Here is a better explanation of the redytemp.
Hot Water Circulator

[TrapperL]

goldenncmom, you do not want any recirculating system that requires the water returned to the heater. Hot water is water with heat energy stored in it. A lot of our electricity comes from steam or water with heat energy. So we pump HOT water to the appliance/fixture but it has lost some of the heat, which is also energy. Do you have any idea where that energy went or what it did? If you have copper lines for your water supply I can tell you exactly what work it has done. It's eating away at the copper lines. Hot water does not simply cool off, the heat energy has to go somewhere and attacking the lines is a common issue with these types of systems. I've replaced far too many of these types of instant hot water systems with under counter small heat units. But beware that the under counter type heaters are rated by how much they drop the incoming water temp, not by how hot they heat the water. If they are designed for a 30F rise and the incoming temp is only 40F, it's not going to do much of anything that you'll notice. If the incoming water is 100F and it raises the temp 30F, that's hardly enough for a dishwasher to work correctly as they require 140F to work right. So be aware of these issues before spending more hard earned money on something that really doesn't work. These under counter units also make an electric meter spin real good too when they are working.
Depending on the design of the house, you may be able to come off of the manifold or a cold water line and replumb to have a heater put on that end of the house. With some of the newer Pex systems you have all kinds of flexibilty but that's something you'd have to discuss with a plumber in your area. It may or may not be feasible. While I'm not a fan of H/W heaters in the attic, it could be an option but access may be an issue.

[Oliver_UpGreenYourHouse]

Hello goldenncmom,
here are a few (late) answers and my own experience:
1. Yes, the water comes back to the waterheater through the cold water line and will have to be heated again. But the water is probably warmer than the city water since it was in the house pipes. Cold water has to be heated either way because the water drained from the hot faucet has to be replaced.

2. Some of the pumps come with a timer build in. The timer is a way to reduce the times the pump has to run but there are better ways to do that using a switch or a motion detector that turns the pump on when somebody enters the room. this way the pump runs only for a few minutes a day and really minimizes the waste. Mod Cut Link

3. The pump I am using uses only 25 Watts and I think I do save energy with my setup. I can not say for sure because I switched to a more energy efficient water heater at the same time I installed the pump. The pump has been working well for 2 years now.

4. The material cost for the pump is about $200 and it could be installed by yourself if you are somewhat handy.
Sorry for the late reply, I hope this still helps.

[4GreenerFuture]

Hot water recirculation systems utilize a hot water recirculation pump designed to recirculate cold water out of the hot water pipe back to the water heater using the cold water pipe as the return path. Hot water "circulation systems" utilize a "dedicated hot water pipe loop" that leaves the water heater and runs through the home connecting to all hot water sinks, showers, dish washers, etc. on the loop, then returns back to the water heater cold water inlet or drain valve of the water heater (connecting to drain valve is said to help prevent sediment from building up in the bottom of the water heater as a result of the returning water stirring up anything on the bottom of the water heater). So, there are two distinctly different types of systems. One that "circulates" hot water through a hot water loop and another that "recirculates" cold water out of the hot water pipe by pumping the cold water into the cold water pipe where it eventually returns back to the water heater.

The cost associated with operating these systems depends on a number of factors;

1. Is water heater gas or electric or tankless?
2. Are the pipes insulated to minimize heat loss?
3. Are the pipes buried in the foundation on the home or in the walls?
4. Temperature of the water maintained in the pipes
5. How often the pump runs per day
6. How long the pump runs during a pumping cycle
7. What is the flow rate of the pump?
8. What is the outside temperature
9. Size of pipe, pipe material, etc.

Today's pumps are fairly efficient and are typically between 25watts to 60watts for residential hot water circulation systems.


Once a home has been built it's rather difficult to install a dedicated hot water loop. Hence, hot water recirculation systems were created.

There are three recirculation system configurations;

• PUMP INSTALLS AT WATER HEATER AND THERMOSTATIC VALVE INSTALLED UNDER SINK

ADVANTAGE: No power required under sink

DISADVANTAGES: Uses Normally-open thermostatic valve (Comfort valve, by-pass valve);

1. Hot water line siphoning / needless demand on water heater: Anytime hot water is not at the sink the valve returns to its normally open position. Under this condition, anytime cold water is used in the home (causing the cold water lines pressure to drop) water from the hot water line will bleed water into the cold water line resulting in demand on the water heater during cold water use i.e. flushing toilet, watering lawn, etc.
2. Continuous Pump Operations: To maintain ready hot water at the sink during scheduled ON time periods the pump must run continuously.
3. Long wait times for cold water: As a result of pumping continuously to force water that is below the thermostatic valves closing temperature (as stated by manufacturer "As the temperature in the hot water line hits 98º the valve closes.") water that is 97º or cooler is pushed into the cold water line at the rate at which heat loss occurs in the pipes. (YouTube has a video of a thermostatic valve system installed in the home and the owner of that system timed the wait time for both hot and cold water. It took 80 seconds to get cold water from the tap where the thermostatic valve was installed.)
4. Thermostatic valves are not calcium proof (hard water friendly) and have a history of requiring replacement and are even stocked at the 2 big home stores. Prices for these thermostatic valves vary.
5. Limited to Time-of-Day hot water readiness. Households with occupants who live busy or non-routine lifestyles result in limited convenience and frustration.

• PUMP INSTALLED UNDER SINK WITH BUILT-IN CHECK VALVE

ADVANTAGE: Pump operations are based on Time-of-day and water temperature


DISADVANTAGES:

• 1. Additional cost to have power outlet installed under sink (estimated $75)
  2. Loss of cold water comfort. One-way check valve only prevents cold water from entering into the hot water line, but it does not prevent hot water from siphoning into the cold water line when cold water.
  3. Demand on water heater when cold water is used.
  4. Limited to Time-of-Day hot water readiness. Households with occupants who live busy or non-routine lifestyles result in limited convenience and frustration.

• PUMP INSTALLED UNDER SINK WITH BUILT-IN CHECK VALVE, SOLENOID VALVE AND INTELLI-CIRC CONTROLLER

ADVANTAGES: Pump operations are controlled by Intelli-circ controller

1. Intelli-circ controller can be configured to activate the pump using push-button single-cycle on-demand, or using a timer, or using occupancy sensor or a combination of modes simultaneously, i.e. using both on-demand and time-of-day simultaneously. This allows for hot water to be convenient for occupants regardless of lifestyle (routine 9-5 work schedule / not routine; doctors, pilots, family members showering at different times of the day, etc.)
2. Timer allows for unique day-of-week scheduling (weekday vs. weekend)
3. System solenoid valve and check valve prevents hot water siphoning into cold water line during cold water events, preventing unwanted demand on the water heater.
4. Utilizes temperature based cyclic-pumping which reduces pump operations. If hot water is present in the line the pump is disabled.
5. Adjustable temperature control allows home owners to control their first out hot water comfort temperature. If they want instant hot water that is hotter they can raise the temperature dial.
6. There are models that do work with tankless water heaters.
7. Cyclic-pumping extends the life of both pump and water heater.
8. Internal pump cartridge replacement at end of life can be performed on-site in a matter of minutes without having to remove old pump with a new pump.
9. Built-in momentary-contact integration allowing homeowners to integrate hot water convenience with smart home devices, i.e. WeMo and "Hey, Siri" or Amazon Alexa or any other smart home device which can perform a momentary contact of two wires.
10. Choosing a lower temperature setpoint (minimum 40F) allows for pipe freeze protection for inaccessible pipes hidden in walls and floors (using other systems on the market which don't allow for lower temperature setting would significantly increase water heating bill when used for pipe freeze protection).

DISADVANTAGES:

1. Requires power under sink.
2. Higher initial investment (less demand on water heater may justify)

SUMMARY or TAKEAWAY

It's not the energy consumed by the pump that people should focus on. Rather, the focus should be placed on the additional demand at the water heater. Maintaining hot water in your pipes 24 hours a day is not without consequences. However, minimizing hot water readiness to specific hours in a day (2 hours in morning and 2 hours in evening) may not see a change in their energy bill. The more water that passes through a home's water heater, the more energy it consumes. Having to wait for cold water is the result of inefficient flow control or over pumping. If your system causes you to wait excessively for cold water then expect to see a higher water heating bill. If you water your lawn at night and notice that you have warm water in your cold water pipes, consider whether heated water is passing through open thermostatic valves could be the cause.


Installing a hot water recirculating pump that operates based on time-of-day in a home where the occupants "do not" live routine lifestyles will likely result in the occupants running the system 24 hours a day in an attempt to have convenient hot water anytime they are home.



THE DAY AFTER
Waking up in the morning and realizing from now on you will no longer be wait 1-3 minutes for hot water at a sink or shower, like you have for years and years, is a great feeling. Every time you use hot water for the next week or so, you'll actually feel pretty good inside (even more so, if you installed the system) knowing that your saving water and you've changed your life for the better. I know, because after all the hours in research and understanding of the different systems and installing the system myself by connecting 4 hoses under a kitchen sink and waking the next morning without having to wait. I smiled every time I used hot water for at least the next 3 days. It is a life changing event that's appreciated every day.


I hope this information helps others discover the joy of living in a home where you don't have to wait for hot water (or cold).


DIRECTLY ANSWER INITIAL QUESTIONS:

Question#1 Is the water recirculated back to the tank and dumped into the top?
ANSWER: Yes

Question: What I have read is that this can cause your gas bill to increase because the tank has to constantly reheat the recirculated colder water. Is this correct?
ANSWER: It depends on how often the pump runs. Constantly is not a word I'd use here. Any water that is recirculated would be reheated. But, remember, it is possible that the water coming from the city could be much colder than the water being recirculated. Reheating circulated water could require less energy than reheating much cooler water that would have entered the water heater when water is wasted down the drain waiting for hot water.

Question: Could this be resolved by putting the pump on a timer so that it is just circulating hot water through your pipes at the most desirable times? (In the morning for showers, and the evening for kitchen activities and dishwasher).
ANSWER: Timers can help in minimizing demand on the water heater. It is energy smart to circulate water for long periods when hot water is not intended to be used.

Question: I am under the impression that these pumps save water instead of having the cold water run out of the faucet until it gets hot and go down the drain, is this correct?
ANSWER: Depending on your current wait time for hot water to arrive, directly factors as to how much water you would save. One person waiting 60 seconds one time each day for 365 days is equal to running a faucet for 6 straight hours. (1 min X 365 days / 60 = 6.08 hours.

Question: I have also read that these devices run on electricity and can cause an increase in your electric bill. Again, is it possible to use a timer to minimize this?
ANSWER: The pump power is similar to a 40 watt light bulb...it's not much at all. The energy cost is from the water being reheated. Most systems come equipped with timers.

Question: Is anyone able to report on the actual performance of one of these pumps? Does it work well? How much has your electric/gas bill increased as a result?
ANSWER: We operate our system using on-demand and "Hey, Siri" to activate a single pump cycle. We are no longer waiting a minute to a minute and a half each time we use hot water.

Question: What is the approximate cost to install?
ANSWER: We installed our system ourselves under our kitchen sink and used the available wall socket that our dishwasher was plugged into. We considered the kind where the pump is installed on to the water heater, but didn't want to go that route for obvious reasons.