Installation was easy in our new home. However, the water would not get more than luke warm. Thanks to those in the Amazon Community that tried to help me, thinking I had a bad sensor. But that was not the case. After days of phones calls between WATTS and Rheem (maker of our water heater), I found out from WATTS that this pump is not compatible with all makes/models of Hot Water Tanks. They new specifcally of my model and that the pump would not work. However, they do not mention that in the on-line specification - and they acknowdged this lack of information themselves when I asked. So, my recommendation is to check with WATTS to be sure your are good to go, first. You can actually start by looking at your User's Manual for your Hot Water Tank and look for the "Heat Traps" in the Nipple connecters on top.

This issue is the "Heat Trap" in the "Nipple" of the inlet and outlet of the Hot Water Tank. This Heat Trap is to keep the heat in the tank for efficiency. However, with this WATTS pump you are actually circulating the heat out, so defeats the purpose of the Heat Trap. Problem is, to remove the Nipple with Heat Trap from the Hot Water Tank and replace with a normal Nipple is next to impossible. Could not get the Nipples off with a large pipe wrench (even looked on YouTube - risky for damaging Tank). So, I plucked out the little "flaps" that are part of the Heat Trap (see picture) and the pump works better, but still not as advertised. I know removing the flaps likely voids the warranty on my Hot Water Tank, but I wanted the Hot Water! Disappointed.

I can only score a 3 for this pump becuase, 1) WATTS does not state anything about incompatiblity in the specification, and 2) it is not delivering the hot water as advertised in my case, even after taking out the flaps in the Heat Trap. I like the product, easy to install, was really excited about it, but disappointed. I have a couple more days to decide if I will return it. It is better to have pretty warm water rather than very cold water out of faucets for a long time, so maybe keep the pump. We'll see...

Overall the pump works well, but the supplied temp sensor valve was defective - see below.

Overview:
Our house is slab on grade with the pipes going underground so we'd have to run the hot water for up to 5 minutes to get all the cold water out. The pump makes a huge difference.

I highly recommend using the pump with a Wemo smart plug, rather than relying on the built-in timer (thank you to another reviewer for this suggestion). This allows anyone in your household to control it from their smartphone, tablet or Alexa - you can turn it on/off and set up as many programs as you want. I set up an "auto-off" program that automatically turns the pump off after 10 minutes, along with programs that turn it on at various times of the day. I can tell Siri to "turn on the hot water pump" anytime; it will run for 10 minutes and turn off by itself.

Issues:
IKEA sinks - If you're installing the valve under an IKEA bathroom sink, there's one minor challenge. IKEA sinks have the P-trap against the wall in order to allow for drawers underneath the sink. This means you won't be able to attach the valve to the wall if you use the supplied water hoses, because the hoses aren't long enough to get the valve below the trap. There are a couple options. One is that you can just zip-tie the valve to the drain pipe, which is what we did. Another alternative is to go to your local hardware store and buy longer water hoses.

Defective valve - the supplied temp sensor valve was defective - it continues to allow a small stream of water through even after it's hot, so we end up with a lot of warm water in the cold water line. I contacted customer service via their 800 number. They're friendly and easy to work with, and I sent in my purchase documentation. But now it's been 3 weeks and I haven't heard anything back, so I'm holding back two stars. I'll update this review once I get the new valve and have it installed.

Pros:
- Easy for my plumber to install
- The pump installs on your hot water heater, so you don't have to make space for it under your sink
- Clear installation instructions
- Works great with a Wemo smart plug

Cons:
- Defective hot water valve

This is an outstanding product. Very easy to install. All you need to install is pipe wrench to remove the cold water feed pipe fitting. The easiest way to make the connection is purchase a SharkBite 22441LF 3/4-Inch FNPT SharkBite available from Amazon. Took about an hour to install. Hopefully you will have an electrical outlet near the hot water tank. The pump will operate on a timer, always on or off. Hot water available at every faucet without waiting for gallons of cold water exists the pipe. Glad I purchased this item.

Awesome product. Installed the pump on top of the water heater in just minutes. After you turn off the water, don't forget to drain down the water heater a bit before you disconnect the hot water outlet pipe as the hot water wants to expand out of the unit once the water pressure is off.
The plastic sensor unit that goes under the sink was also very simple and easy to install. I actually rotated the existing hot and cold water valves (mine are attached with compression fittings) about 90 degrees to make the hose attachments easier. If you do this make sure to check for leaks from the valve which can be fixed by simply tightening the compression nut. One word of caution however, be very careful NOT to cross thread the metal hose fittings onto the plastic sensor. I cross threaded one of the metal nuts and it was a bear cat to get it screwed together properly to avoid a leak. I installed three sensor units, one in our kitchen and the other two in our two bathrooms.
Now the kudos: First, we turn our pump on before we need hot water and let it run for a few minutes, these results are based on that action. Our guest bathroom took almost 90 seconds to get hot water to the bathtub, now it's about 15 seconds. Our master bathroom took 45 seconds to get hot water at the vanity sink, now it's instantaneous!!! Our kitchen faucet took 35 seconds to get hot water, now it takes 3 seconds!! We're very impressed with this product and are really excited to save a ton of water in the coming years.
If you are good with your hands you can easily install this product and the three sensors in under an hour. If not, you should hire a plumber which will be expensive, but in the end worth it in water savings and the cost of heating your water.

Great product, at a $50 less than the two big box stores, plus no tax. This pump is extremely easy to install, but it isn't necessary to go to the extremes of shutting off the gas and draining the hot water heater, which may create a leak problem in old heaters. Turn off the cold water valve at the top of the heater and turn on the hot water faucet in the house. I drained a bucket of water, from the water outlet, located at the bottom of the water heater and then loosed the 3/4" hot water outlet nut slightly, on top of the water heater, to allow the air to drain the water back out of the pipes, so you don't have it all over you and the heater, like I did on the first one I installed. Then install the pump, as directed, turn the water back on, then go in the house and turn off the hot water faucet. Determine where you want to install the sensor, turn off both faucets and install the sensor. If both faucets won't turn completely off, find another location nearby and try that one, as a last resort simply turn off the water to the house, but be sure to leave a cold water faucet on so that when you turn the water back on all the air will purge from the pipes. This recirculating pump will definitely give you quick hot water, like you haven't had in the past, but you will now get lukewarm water out of the cold water faucets, when the pump is on, not cold water like before. I consider this a small trade off for the comfort and convenience of a nice hot shower, without standing around wasting water, while you wait for the water to warm up.