I have essentially the same layout, WH, and LP as you.

If you can easily and cost effectively run a dedicated return line and use a common recric pump then that is the best solution all things considered.

If you can't then search the forum for Autocirc. I faced the same question and opted for the recirc pump retrofit using the cold line as return.

There are three choices in design for retrofit pump...

1. push button when hot is desired then wait and requires AC at the farthest faucet

2. Watts and Grundfos Comfort series run the pump all the time or on a timer. Requires AC at the WH for the pump and a passive thermal valve at the farthest faucet

3. Autocirc thermally activates the pump when hot water temp at the installation point (farthest faucet from WH) drops and offers timer also. An all in one solution (pump and valve installed at the farthest faucet) that requires AC the farthest faucet.

The Autocirc is the only offering that thermally controls the pump so you can leave it switched on all the time but the pump only runs when the water temp drops.

Have had an Autocirc since 2003 set to always on and never noticed any increase in electric bill but a slight drop in LP usage and a significant drop in water use. All in all I've been very happy.

1. pay $597 (SRP, look around street price is lower) for a new one and it will screw right in where my old one was.

2. pay $180 (street price) for the Watts solution (seems to be made for Watts by Grundfos) and have to install two components at different locations

3. pay $220 (street price) for the Gundfos Comfort series and have to install two components at different locations and expect that they make a better product for themselves than the one they OEM for Watts

Autocirc and Grundfos offer two year warranties from date of pump manufacture or one year from date of pump sale (kinda cheesy) while Watts offers a one year warranty.

This post was edited by justalurker on Mon, Oct 13, 14 at 17:14

The HSX heat tape looks simple enough to install and use about same energy as a recirc pump if both were on timers.
A 20 or 30 gallon heater in crawlspace wouldn't cost much more than a pou heater. If you can do the install,here's some engineered options for a larger heater. Retrofit with 1 2kw or 2 1kw 120volt elements utilizing existing 20A 120V circuit ( have you checked wire size because it might be 10ga). Recover isn't very good with only 2kw heat but recovery isn't important if supply comes from main heater. A couple of extra ball valves would make it simple to switch supply coming from hot or cold. If LP ever gets more expensive than electric, a 240V circuit could be pulled, origional elements reinstalled and ball valves set for cold supply taking load off main LP heater. If I were going this route with 20 or 30 gal,I would (A) install a pilot lamp connected to a potential relay so those in line for showers could see exact time of recovery and adjust morning routines for best advantage. (B) Add Insulatation and timer on tank. Again pilot lamp would alow setting timer for maxium advantage.
If it's on your time and dime,we'll talk you into one more Rube Goldberg set-up.

Justa and Klem:

Thanks for the replies and ideas. It sounds like I should go back to the recirc pump idea, at least in the short term. My DIY skills are at least average, maybe a bit above that. I'm not scared to handle wiring/terminating with 120V, or doing some sweat joints if necessary. That said, I don't have a lot of free time, so the simpler solution the better, to some degree.

Justa - I will have to go back to my recirc research, but I thought I had found a few more options than you listed. Is there some reason a dedicated return line is better than the "crossover" types that use the cold line for return? The only downside I've read about is a few seconds of lukewarm water on the cold side when used, but that doesn't concern me much. installation is certainly easier with the crossover, but I could fairly easily run a dedicated return is there was enough upside to it.

Klem - your thoughts are in line (pun intended) with what I had been mulling over with adding another tank. Interesting thought to put lower-wattage elements in to keep it 120! However, it sounds like you see this installed with input from the existing hot water pipe? Is that "legal", i.e, it won't cause problems for the electric heater? I thought I had read somewhere that incoming water had to be more or less cold. Also - not seeing how that would be better than an inline mini-tank, really, other than the option to go to full 240V down the road. FYI, with the cost of our propane around here, I think it's already about even to heat with electric vs. propane. I figured if I could avoid heating that lengthy hot water line in the crawlspace, I'd be ahead a bit in $$ - but maybe not.

And I'm not giving up on the heat trace idea - I have a call in to one of the companies to discuss. Initial cost and ease of installation seem pretty reasonable, but not sure yet what operating costs would be. I would also think it would last longer than a recirc - I like no moving parts, though I suppose the cable itself could fail due to the repeated hot/cold cycles.

A dedicated return line is what the (stubborn) plumbers like and eliminates the (unsubstantiated by fact) concerns of hot water in the cold line. A plumber quoted me over a thousand dollars to retro install a dedicated return line and that did not include sheet rock repair, painting, and inconvenience to us during the job. If I were a plumber I'd tell everyone who asked that the only way to do recirc right is with a dedicated return line so I could put my kids through college or make a few mortgage payments. I have a buddy who works at the state lab and I've had him check my cold water at the farthest faucet, where the Autocirc was, numerous times and he's given the water the official OK for safety (potability). If I were buying a new home I'd have a dedicated return line plumbed and eliminate the need for a temp valve at the farthest faucet just to eliminate that one part, BUT it would be better to design the pluming layout and centrally locate the WH so there was no (stupid) long run to a farthest faucet on the other end of the house.

As I posted in earlier threads... tepid water in the cold side is never worse(?) than a few seconds wait and not nearly as long a wait as the minute(s) it took to get hot water at the farthest hot faucet. We got used to waiting a few seconds when turning on the cold faucet in days and never gave it a second thought.

So here I am tens years later with no ill effects from hot water dribbling into the cold water line at the farthest faucet and absolutely trouble free service from the Autocirc. I spent a couple hundred dollars for the Autocirc and I've saved that cost many times over just in water bills, not to mention that in the SW saving water is a priority, and I'm going to buy another retrofit recirc... just not an Autocirc.

Since both our houses have a similar layout and water heater size and are LP I am particularly qualified to recommend the retrofit recirc pump without hesitation based on my first hand experience and not theory or conjecture. Unless you get a Monday or Friday recirc pump you should enjoy similar performance and service life that I have.

I'm always amused that (some) people will recommend or embrace a far more complicated and costly solution when the simple and easy solution to their problem is right at their fingertips. I'm off to the store to but a Watts or Grundfos.

Let us know what you decide.

You are using propane - don't install a circ pump on a timer - they are expensive to operate in heat loss. Instead, if you want a circ pump do an on-demand and use a push button or a motion detector.

You want to install an insulated dedicated return line if you do a circ pump. Do it in PEX and you can do it cheaply. Don't run it back through the cold water line if you can help it.

Alternative: Install the mini-tank on the hot water side. It will supply enough hot water until the main unit takes over.

Also, consider a heat pump (hybrid) water heater instead of your propane heater... will save you hundreds of dollars a year.

""You are using propane - don't install a circ pump on a timer - they are expensive to operate in heat loss"

Has not been my experience over a 10 year span.

Hi all. After batting around several options for far too long, I finally bit the bullet and ordered the Grundfos recirc unit. Of course, immediately after doing so, I found this tidbit on the RedyTemp website, that has me more concerned than any of the other "cons" I found about the crossover recirc systems:

"COMFORT VALVE HOT WATER CIRCULATOR PROBLEMS
According to nearly 100 trade professionals attending the 2006 Southern California PHCC trade show, homeowners with Watts and Grundfos thermostatic valve hot water recirculating pumps experience excessively high monthly gas bills and waiting for cold water. A closer examination and understanding of thermostatic valve functions identified the costly inefficiencies and loss of cold water inherent with these systems. Comfort valve hot water circulators utilize a pump installed at the water heater connected to the hot water supply pipe. By design, these pumps must run continuously (continuous energy consumption) to prevent the "normally-open" thermostatic valve from opening. It should be noted that heater mounted pumps often have narrower connection fittings than the water heater's actual pipe reducing flow capacity and load fulfillment capabilities.
Thermostatic valves or sensor valves install under sinks connecting the homes hot and cold water lines together. Material within these valves expand and contract (open / close) depending on the temperature of the water contacting the valve. These "normally open" thermostatic valves close when 95F degree water contacts the valve, preventing hot water from entering the cold water lines. This being true also means anytime less than 95F degree water contacts the valve the valve will be open. Any use of cold water, i.e. toilet flushing, watering lawn, etc. drops the water pressure in the cold water lines but, not the hot water lines. The higher pressure in the hot water line force's water to siphon through open thermostatic valves and into the cold water line even though you intended to only use cold water. Until 95F degree water from the water heater reaches and closes the valve the homeowner is left waiting for cold water. It's important to remember that any amount of water siphoned into the cold water line is instantly replaced at the water heater with very cold city water. Thus, repeatedly placing demand on your water heater when using cold water."

Justalurker (or anyone, of course), in your long experience with the Autocirc, did you experience anything like this (hot water demand when using cold water)? I'm hoping this is seriously overstated, and/or depends on ambient line pressure, etc., that won't be a problem in our location! Otherwise, this seems like a serious design deficiency in these "comfort" systems.

Thanks again for the opinions.

I have friends using the Watts/Grundfos design recirc and they've had no problems, but I don't like the idea of the pump running all the time.

That concern is why I decided 10 years ago on the Autocirc all-in-one design because the pump only runs when the water temp drops and then shuts itself off. Another plus(?) for the Autocirc, IMO, is that the temp valve is in the brass pump housing and not plastic like the Watts or Grundfos... downside is IF or WHEN the temp valve fails you can't just buy that part so you have to replace the entire unit.

If you search the forum you'll find I've said that I never saw a change in my electric bill, saw my LP bill drop a touch if anything, but my water bill went down dramatically not having to wait for hot water at the kitchen sink.

After 10 years with an Autocirc the temp valve failed. After much reflection... I bought another one. It's hard to argue with competence although my experience has been that some people will.

I have some issues with the assumptions on this website, but the argument still deserves some consideration: The conclusion is that the cost in fuel lost far outweighs the savings on water.

Here is a link that might be useful: Will recirculating pump save me money?

Jake,

You keep harping on "the cost in fuel lost far outweighs the savings on water", but that has NOT been my experience during the last 10 years with an Autocirc and I have charted my costs in detail. The link you provided makes ASSUMPTIONS that may or may not be accurate.

Either I live in an alternate universe where your laws of physics and cost analysis don't apply or the(?) conclusion and you are wrong. You think, you read, you link... BUT I lived it.

Everyone should make their own decision but rather than obtuse studies and anecdotal information I submit my own actual hands on, living with the Autocirc, 10 years of experience and costs savings. I'm looking forward to the next 10 years with my new Autocirc of saving money, not waiting for hot water, and not wasting water while I continue to read that I'm not.

Since the installation of an Autocirc is non-invasive, EZ for a DIYer (if you have an AC outlet under the sink), and completely reversible in minutes those interested might give one a try and see for themselves. Then they would know which universe they live in.

Lurker,

Thank you for posting your experiences. It does help provide information. However, one person's reported experiences does not make a definitive answer and there may be other answers that are not the same as yours.

What you have presented is anecdotal information. It's not a controlled experiment, there are multiple factors that are not being controlled for.

In addition, self reported information is often biased (not saying yours is or isn't). Particularly people who have spent a lot of money on a product will insist that they are getting more out of it (This is something we have seen with magnetic water "conditioners", in particular).

I have repeatedly stated that circulating pumps are particularly wasteful when they run continuously and pipes aren't insulated.
They are least wasteful when pipes are insulated and are used "on demand". I'm not the only one to state that - there are others who have. Here is a link from another energy saver who had the opposite experience with a pump. He claims it cost him $3,200 over 8 years in propane.

Note: He also recommends the "On Demand" systems.

Again, I appreciate your posting your experience, we all do- but you build credibility on here by supporting your own claims - not by attacking me.

Here is a link that might be useful: Energy wasted in circulation systems

There is nothing else to do other than report my direct experience which I have and repeat...

Since the installation of an Autocirc is non-invasive, EZ for a DIYer (if you have an AC outlet under the sink), and completely reversible in minutes those interested might give one a try and see for themselves.