i had to install a recircultating system just before we moved in when we dicovered that it was taking 5 minutes to get hot water at the kitchen sink. i don't care what region of the world you live in - hot water is still needed to wash dishes and take showers and it sucks having to wait 5 minutes to get the hot water to flow - i highly recommend it.

the way i did my system saved me a lot of money but i don't actually get instant hot water - i still have to wait about 10 seconds. here is waht I did.

the tankless hot water generators are on one side of the house directlly under the master suite - so there is no delay for those faucets. however, the kitchen sink, island sink, utlility room sink, and main feed to the second floor all exist 88 feet away on the other side of the house (big delay on these). the plumbers ran a main line across the 88 feet span (1 inch for about 44 feet and then 3/4 inch for the rest to keep the water pressure up) and then tapped off of that main feed at the other end of the house to supply the various sinks with 1/2 inch lines. just before the point where they started tapping off the main feed, i inserted a tee (3/4 x 3/4 x 1/2). from that tee, i ran a 1/2 inch line all the way back to the hot water supply (88 feet) to make a racetrack like loop. i also inserted a tee at the supply end just after the tankless water generators (1 x 1 x 1/2 inch). i took the two ends of the loop and tied them into a 4 gallon hot water tank one side had a small water recirc pump that has a thermostat. I insulated the entire recirc loop.

the small hot water tank is what is used to keep the water in the racetrack hot without activating the tankless hot water generators (i did not want the tankless units short cycling to keep the water in the loop hot). if you have a hot water tank - you won't need the small tank like i have..

the plumber that did my house charges 3000 dollars for a similar system. i did mine for about 600 dollars (the small water tank was 140 and the pump was 180, the rest of the cost were plumbing parts).

i would recommend doing this but i would not spend a lot of money on it either. there might be a way they could plumb your house so that you could add it in later yourself. the key is to add in the recirc loop now and make sure that they have the loop insulated.

there are also systems that you can buy that use your existing plumbing to create a hot water recicultaing loop (do a google on hot water recirculting pumps chilipepper). that might also be an option for you - but again have those hot water pipes insulated now.

good luck

First of all, the plumbing codes require that when we install a circulating loop all hot water pipes MUST BE insulated. If you live in Central Florida I would recommend that you take it to the next step and insist that ALL pipes, both hot & cold, be insulated.

On the one hand pipe insulation is cheap and easy to install while on the other hand not only will insulating the hot water pipes reduce heat loss and thereby save you money, insulating the cold water lines will eliminate condensate moisture from forming on the pipe walls and dripping inside you walls.

i didn't give a crap about code - i just wanted hot water at my sink in less than 5 minutes. and i wasn't going to pay a plumber 3 grand to put it in.

it would have been impracticle to insulate all the hot water pipes after the fact - but insulating the main feed and the return was easy to do and did not cost that much.

if you put in a recirc system after the fact (like chillipepper) you probably can't get to all those water lines since many of them are burried in the wall - so you do the best you can do. it might not be as energy efficient as a totally insulated system - but so what. pay the few extra pennies a day to keep hot water circulating in the line.

In Flseadogs original post he is discussing new construction. To that end I made the comment that when installing a re-circ system we are required to insulate all hot water lines and return lines. Obviously this would not be practical for reworking an existing system, but when considering new construction at about $.10 a foot for material and the speed and ease of installation, one would be silly not to install the insulation.

flseadog,

Based on what you've written, it sounds like a hot water recirculating system would be more of a luxury than a money saver for you. So if the cost doesn't justify the convenience of not having to wait for your hot water, then don't spend the money.

Actually, I pretty much find it hard to believe that a hot water recirculating system can save enough money to completely offset all the costs in any single resident dwelling.

After all, in addition to the costs of the extra pipe and insulation (which I'll admit is relatively inexpensive materials) there is the relative significant cost of the motor, the cost of installing the system (unless you do it your self) additional maintenence, and the on going energy expense (because even with insulation, the water is still going to cool faster in the pipes than it will in the tank, so there is the extra energy cost of not only running the motor but also of reheating that water).

So given that in most places, water is pretty darn cheap (and with energy costs seeming to be rising faster than water costs), you have to first convince me that once installed, the added energy costs even offset the water savings. Then if you clear that hurdle, you have to show me how many years it will be before the savings offset the cost of the system. After all, I could easily see a system costing $1,000 to install. If my water bill is only $40/month, it would take over two years for the system to pay for itself if it could replace my water usage. So realistically, it seems like it would take something like 25 years before the system could pay for itself. By that time, you have to start including the extra maintenance (after all, in 25 years, you are likely to have to replace the moter, another $$$ expense, adding anothter 5 years before the system pays for itself).

Now I'll admit that I don't have any hard numbers in front of me, but gut instinct and using a little common sence and some logical ruff estimates of the various costs... I just don't buy the notion that this is a money saver.

So once again, throw out money savings... does the system's cost justify the luxury. If not, forget it.

it's not as much a question of saving money but rather the waste of time standing in front of a sink and waiting for 5 minutes for the hot water to flow. and for some who live in drought areas (like Georgia) that can also be quite expensive and a complete waste of a limited amount of drinking water.

the problem is that for long houses there is a lot of cold water in the hot water feeder pipes that has to be pushed out for the hot water to flow. in my house, the 88 feet of 1 inch and 3/4 inch feeder pipe meant there was 5 to 7 gallons of water in the line. with a 1.5 gpm flow rate on the kitchen faucet you can do the math - it's many minutes to get hot water. this was unacceptable to the DW, and I too found it a pain, so it got fixed.

my point is that you don't have to spend a lot of money to have the "luxury". The chillipepper system is a few hundred dollars and can be installed after the fact. and you don't need to insulate all the pipes which will cost more than the 10 cents per foot for the product once you add in the labor to have all the pipes wrapped and strapped.

it's a good idea to at least have the hot water main lines and long feeder runs insulated and you can do that yourself before the insulation goes in. if you want to spend the extra to have all pipes insulated, go for it.

Thanks for the comments. I'm still undecided so I think I'll ask the plumber for the estimate and see how bad the sticker shock is.

let us know what the plumber is going to charge and what it will include. thanks

Anyone know if the Chilipepper Recirc pump is strong enough to start a Noritz tankless WH when the run will be approx 70' of 3/4" copper line? Our plumber has suggested this pump when we convert to a tankless water heater. Chilipepper cost is approx $216 w/ one remote control.

I've talked with Noritz customer service and they recommend the Metlund pump. Metlund says bec its over 60' I need their biggest pump (list approx $690),

Does anyone have experience with these pumps? We will be going from a 32 yr old elec 50 gal WH to a 7.5 gal Noritz tankless. TIA

napa

I have 2 Rinnai tankless hotwater generators in series and I had to install a recirc pump since my generators are directly under the master suite (nice) but 88 feet away from the kitchen (long wait).

The way I hooked mine up was to actually bypass the tankless hot water generators becuase I did not want the generators to cycle just to maintain hot water in the recirc loop. Instead, i bought a small 4 gallon electric tank and use the small tank to maintain hotwater in the line. If you go this route, then you can use a very small pump (i used the smt-303 laing pump that consumes 30 watts of power - see http://www.hvacquick.com for info).

The recirc loop is connected to the main hotwater supply line just after the output of the hotwater generators - and then at the distant end just before all the branch lines going to various sinks. The supply side of the loop starts as 1 inch and then goes to 3/4 inch CPVC. The return loop i installed is 1/2 inch CPVC. I insulated the entire loop.

The return side of the loop dumps into the 4 gallon tank and then on to the pump which pushes the hot water into the supply side of the loop. I also have a few shut off valves, a bleeder pipe& valve to remove air (very important), and an air vent (also very important).

Laing now makes a new pump that has an integrated check value in it and that made the plumbing easier. I did not see that listed on the hvacquick site - call them and ask about the new pump. otherwise, you have to install a seperate check value - not a big deal, but the value must be matched to work with the pump (the output pressure of the pump is low).

I used the white paper on the hvacquick.com web site (i think Laing also has some info on their web site) but modified it a bit for the tankless connection.

This all started out when I wanted to supply my humidifiers with warm water and I realized that the tankless hot water generators would be kicking on and off whenever the hvac turned on - not waht I wanted. At the same time I then discovered the hot water delay issue. So my recirc system was designed to serve two puposes. I tapped off the recirc loop to supply 2 humidifers and it also keeps hot water in the line for the sinks. It works quite well.

Whenever we turn on a sink at the distant end, we have a short delay (about 15 seconds) for the hot water in the recirc loop to push though the branch lines. The hot water generators kick in to backfill the hot water we use with a new supply of hot water.

Whent he humidifiers kick in - the flow rate is so low that the hot water generators don't kick on (what I wanted) and the line is backfilled with a small amount of cold water. The small hot water tank then heats the water in the loop to the preset temp.

sniffdog,
Thanks for responding. I did read your original post on this thread and thought you had a good set up.
After talking wtih a plumbing supply company today, I'm thinking that perhaps a small (2.5 or 4 gal) electric mini-tank or tankless unit at the far-away sink may be a possible solution to the long run. We have a well and septic system and need to conserve water.

napa

that is another way to solve the problem. if you only one have one or 2 sinks at the distant end then the undersink on-demand generators are a great option.

I purchased my small tank at http://www.itankless.com/. They sell both tank and tankless point of use hot water heaters.

The one thing to watch is the voltage and amperage requirements for the point of use units - they can be quite high (240 volts and 20 amps or more). I selected the Steibel Eltron 4 gallon tank since it only required a 120Volt circuit and 10 amps - and that made it very easy for me to plug into an exisitng outlet in the basement. Make sure the electrician runs the proper lines to the sinks where these units will be conencted - and they should be on there own dedicated circuit.

The issue with the tank units is that they take up more space - even the 4 gallon tank is relatively large compared to the typical under sink space, and of course the supply of hot water is limited to the 4 gallons. With the tankless - the hot water supply is not limited.

If you plan on using the point of use system at the kitchen sink and will be connecting the dishwasher up as well, you have to think through how to supply hot water to both. The dishwasher will drain the little tank quickly an will drive a small tankless generator unit for long periods which might not be cost effective. There are ways to hook the point of use systems up to avoid that - the plumber should know how.

In my opinion sniffdog is correct in his installation when main heater is tankless, use small electric heater to maintain water temp in main hot water line and connect at farthest point.Most tankless manfacturers lower warranty period when circulating lines are tied back to the tankless heater.Using small heater maintains normal warrany period.

Hot water recirc loops should be required in every new construction application. Simply for water conservation. Billions, maybe trillions of gallons go down the drain every year in houses that do not have recirculated hot water.