I have read that a family of four can waste 16,000 gallons of water a year letting the water run waiting on the water to get hot. I am considering installing a Hot Water Recirculation system in my home. My house is a single story home about 1700 sq ft. I saw on the internet about making a manual loop back system where I run piping from the furthest faucet to the discharge spickit on the water heater. Then you are supposed to insulate the hotwater pipes except for the last ten feet of pipe going to the discharge spicket. The theory is that the hot water will expand and automatically force the colder water near the discharge spicket back into the water heater to be reheated. Suposedly the water will keep circulating by convention.
I am also considering buying a pump to place on the water heater along with a special valve that goes on the furthest sink from the Hot Water Tank. The pump forces the hotwater through the system, and the colder water at the furthest point gets forced back into the cold water line. This system uses electricity.
The pump type system cost 200 dollars, but doesnt need any return lines installed. It also cost money to run the pump. If you have any first hand knowledge of either of these systems, I would appreciate any advice. Which type system would you recommend? Is it worth the money? Thanks for any advice.
no...you cant insulate the whole loop if you are going the manual route. if the loop is the same temperature, there is no movement in the loop. By having the last ten feet with no insulation, it cools more thus causing the water to circulate rather than stay stationary. The following I pulled off the Ask the Builder Web Site...
When water is heated, it simply gets lighter. It wants to float to the top of cooler water. Cool water wants to fall. If you have a loop that projects upwards, the cool water wants to fall down the loop while the hot water goes up. Gravity fuels the motion.
It works in this fashion in your house. You already have half of the loop in place. This is your hot water piping distribution system which begins at your hot water heater and ends at the farthest fixture which requires hot water. If you were to install copper piping leading back from the farthest point and from other high points in the existing system, you would have a loop. This return loop connects into the bottom of the hot water heater where the current drain valve is located. It is that simple.
The flow of water through the loop is very slow. However, that doesn't matter. The only thing that is important is that hot water is near each fixture. Without a loop there is no movement, so any movement is better than none!
Non-Gravity Systems
Those of you who live in a house on a slab or where a majority of the hot water lines drop below the heater need to use a recirculating water pump. These are simple devices that connect in line in the loop. They are often located near the water heater, however, they can be anywhere in the loop. The pumps circulate water at low pressure and low speeds. Once again, there is no need to have lots of water moving through the loop. It is just important that the water is hot near the fixtures.
If you install one of these pumps, remember that you need to install unions on either side of the pump. Unions are special fittings that allow you to break into the piping system and reconnect without soldering. Water meters are always installed using unions. Look at yours and you will see what I mean.
Insulation
Once you decide to install a recirculating loop, you need to be concerned with energy loss. The loop will work fantastically without insulation. In fact, it works best without it! But, this can also cause your water heater to cycle on and off more often. Remember, you are bleeding heat from the heater when the loop contains hot water.
There are numerous ways to insulate the pipe. Many insulating materials are made exclusively for water piping. They fit snugly over different sizes of pipe. Some insulation, like the foam types, must be installed as you install the pipe, not after the loop is constructed. When you select your insulation material, ask how and when it should be installed.
Piping installation methods must also be altered. Some people attach water piping to the sides of floor joists. You can't do this with an insulated loop system. The pipe must stand away from floor joists so that the insulation is not crushed. Special inexpensive pipe hangers allow you to do this easily.
All of the hot water lines that lead from the heater must be insulated. They need to be insulated up to where the return loop lines connect and slightly beyond. The return loop also needs to be partially insulated. If you insulate the entire system too well, it may not work! Remember, the water has to cool at some point for the loop to start its gentle movement. I suggest that you leave the final
15 feet of return loop uninsulated.
Beginning the Loop
Houses that do not have a recirculating loop system have hot water pipes that branch off a main line and stretch to each fixture. The ideal loop system would have you start the return loop as close as possible (within 2 feet) to each fixture. The closer the return loop starting point the closer hot water will be to the fixture.
Your existing home can benefit without getting this close to a fixture. As long as you can cut the distance in half or more, you will see a much more rapid hot water access time.
The return loop begins with a simple tee fitting as close to a fixture as you can get. The tee simply creates a right or left turn leading the way back to the water heater.
On your way back to the water heater you simply create other connections as other return loops join the pipe on the way back to the water heater.
Air Locks - BIG PROBLEMS!!
As you construct your loop system, you must be concerned with air traps. What are these? Well, you know the drain traps under your sinks? Imagine if you did this upside down with a water line in a loop system? You would capture air in this trap since air is lighter than water.
Air can get into a plumbing system in any number of ways: a water main break, a repair process in your own home, dissolved air within water, etc. If you create a trap, the air will collect in the trap and BLOCK movement of water within the return loop. Air is not a problem in the regular water piping system. The rapid movement of water through the pipes when you turn a faucet on pushes the air out of the way. Remember, water moves sloooowly through a gravity loop.
Check Valve
Just before the loop enters the bottom of the hot water heater you might need to install a simple check valve. These are one way valves. This valve will prohibit in-rushing cold water from the bottom of the hot water heater from flowing backwards through the loop when you open a hot water faucet somewhere within the system.
Check valves are not always necessary. Some systems need them because of friction loss and other obstructions that make it easier for the hot water to flow backwards through the loop rather than the correct direction - from the top of the heater!
These valves can be installed after the loop is completed. Install it in the vertical loop pipe just before it enters the hot water heater. You might want to try installing the loop first without one and see what happens. If you begin to get cold water at a faucet when you should get hot, you know you need a check valve.
Final Connection
As the loop returns to the water heater it connects at the low point of the heater. This is always the location of the heater drain valve. This valve is simply screwed into the heater. Attach a wrench to the valve and turn counterclockwise. It will come out.
Install an insulated nipple in place of the valve. This will minimize corrosion possibilities. Then as soon as possible install a tee fitting with female threads at the tee. If you use the right one, the drain valve will screw right back into the tee. The other end of the fitting allows you to connect the loop to the heater.
Shut Off Valves
While on the subject of valves, let's talk about the shut off valves on top of hot water heaters. I have seen some aggressive homeowners install a shut off valve on both the hot and cold water line. They thought this would help in the event they need to switch out the heater. Well it does help. It also creates a potential BOMB.
If some idiot turns off both valves (happens everyday somewhere), and the pressure relief valve malfunctions or was never installed, and the heater thermostat malfunctions, the heater will explode. It has happened more than once.
Only install a valve on the COLD water line, never on the hot line.
With a pump system you could install a timer on the pump to turn it off when you are not likely to need hot water. I have toyed with the idea of putting a pump system in my house and putting a momentary push button switch at the bathroom vanity hooked to a timer/relay which would turn the pump on long enough to get HW to the faucet. Larry
I doubt that 16,000 galons is correct. And I doubt that there will be a resonable payback of your investment. I think the only reson to consider these systems is for your conveinence so you don't have to wait for the hot water. So do the install if you don't want to wait for hot water but I doubt it will save you any money.
I bought one on EBay that is a Laing autocirc 2. It works pretty good. Paid a lot less than $200 for it. Water at the farthest tap from the water heater is always hot when I need it to be. Before I would wait about a minute for the hot water to show up. There is a timer that you set to run the small pump that can be set in half hour increments for the entire day so that it is not running when you don't need the hot water. The valve that is under the sink only opens up when the water temp goes below the set point, thus allowing the water to circulate back to the water heater and push warm water to the valve. When the them reaches the set point, it closes. The only thing that I do not like about it is that the cold water is now warm and you run into the same problem if you want cold. This is not really a big problem as I usually keep a jug of water in the fridge to drink and any other use of water, warm is not a problem. I had a problem with the pump making a little banging noise, called Laing, and they sent me a new impeller that was redesigned in a few days.
I like it, not so much for the money savings, but for the not having to wait part!
I read "with a pump system you could install a timer on the pump to turn it off when you are not likely to need hot water" and that is exactly the timer the Laing Autocirc has.
This leg of the discussion is about "I have toyed with the idea of putting a pump system in my house and putting a momentary push button switch at the bathroom vanity hooked to a timer/relay which would turn the pump on long enough to get HW to the faucet."
No sir, I responded to the sentence JUST BEFORE what you are quoting... "With a pump system you could install a TIMER on the pump to turn it off when you are not likely to need hot water. I have toyed with the idea of putting a pump system in my house and putting a momentary push button switch at the bathroom vanity hooked to a timer/ relay which would turn the pump on long enough to get HW to the faucet".
Do the math. For your size of house I would suspect that the longest run is less than 50' so each draw through will be less than 1 gallon. To waste 16,000 galons a year you would need to do over 40 draw throughs per day! You likely aren't doing anywhere near this amount.
Seems like a complicated answer/solution to a minor problem?
For the added convenience of hot water within a few seconds of turning on the tap?
Add the financial and ecological costs of manufacturing, buying, installing and maintaining another pump; and it's running costs; is it worth while? Also, while probably highly reliable it's something else to go wrong?
In our house the longest run from the electric hot water tank is about
40 feet of half inch copper pipe. That's about 120 cubic inches of hot water in the pipe that will cool down from around 140-150 F to house temperature; releasing it's heat within the house envelope. Same as we leave warm shower/bath water in the tub to release its heat into the house!
Since at least 9 of the 12 months here require some electric heating the so-called 'lost heat' is not only very minor but it offsets electric heating! Considering the amount of water (if actually wasted?); it is much less than one flush of even a low water usage toilet?
I think any reasonable analysis quickly concludes that energy isn't the main issue. It's the convenience of having hot water quickly when you want it. And anyone who's had a large house with a long run for the hot water knows it can take awhile to get hot water. I see nothing wrong with installing one of the pump systems with a timer and temp control. You could also use a motion sensor to get the water going as soon as someone enters the area, which I think would likely be an optimum solution.
My previous house took over 90 seconds to get full temp hot mater to the master bath. Yes, it was a stupid plumbing plan. Even worse was that the master shower and master vanity were independent runs.
My new house has a timer based recirculator for morning showers. It's fantastic.
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