Do any of you have a hot water recirculating system that is activated when you walk in the room? If so, what sensor do you have on the wall that activates the system?
Provide some details on what you are trying to accomplish. Is it getting hot water to a second story master bathroom - trying to eliminate running a shower for 5 minutes in the AM to get hot water? Or is this a widespread problem for all rooms on the second floor. Is it a kitchen sink problem?
What type of hot water system do you have - tank or tankless. Where is the hot water system - basement?
if this happens to be a master suite/second floor problem, I need to know how your sinks are condfgured, where you have switches and outlets and where you want the motion sensor.
I can find the info you need.
Our home is 2800 square feet, 1 story. Regular hot water heater is at one end of house--garage, master bathroom is at opposite end. We are trying to get hot water into the master bath when we walk in using a motion sensor, but now are thinking about just a switch in case we don't want the hot water on.
is there a basement - or just slab? do you have any idea how they plumbed over to the master suite? do you know the diameter of the pipe they used? did they run one large feeder (probably either 1 inch or 3/4 inch pipe) and then branch off of that with 1/2 inch pipe to feed the sinks and shower? how far away is the hot water tank from the master bath? this info would help in pump selection.
I have pretty much the same problem. My house is 100 feet wide with master on main level. we put hot water tankless in basement under master suite side but kitchen and 3 other sinks are on the opposite side. having the basement made adding an additional reactrack recirc loop, small electric hot water tank, and pump not to difficult.
if you are on a slab, then you will need to use existing pipes to circulate the water. During my research I found a nice little pump system that might work for you - but it depends on your plumbing.
my thought is to put the pump under a vanity sink in the master suite - primarily so that it will be easy to provide a power switch or motion sensor switch to control the pump. the concept is that you provide a bridge between your hot and cold water supply tubes (they make a special fitting for this) feeding that sink. The pump sits in this bridge. When the pump is off, the hot water supply flows to hot output of faucet, cold supply flows to cold output of faucet. But when pump is on (faucets are off), the hot supply flows over to the cold water supply.
Initially when you turn the pump on in the AM, you are essentially taking cold water (curreently in the hot water line) and moving that into the cold water supply for the sink. This process is drawing hot water up to that sink - no water is running out, just being moved around inside the pipes. this pump system has a built in thermostat you can adjust so the pump will automatically turn off when the hot water you darw up reaches the temp you want. The tstat is critical because it also keeps the hot water you draw up from constantly flowing into the cold water supply because then you would be heating your cold water supply and wasting money.
As long as the hot water supply feeding the sink is being supplied via a main feeder AND your shower is also tied into that same feeder - then when you turn on the shower (after running the sink pump for 5 minutes or so) the delay for hot water out of the shower should be very short. you can test this right now by manually turning on that bathroom sink (do this in early AM when hot water is cold) and running it until hot water comes out of that sink. then go over to shower and turn on hot water - hot water should flow within a short period of time. if that test works - then this pump system I speak of will work for you.
power for the pump would come from a nearby light switch close to the vanity - it could also come from an existing outlet on the wall above the vanity. i can design the pump circuit so you can use either a flip switch or use a motion sensor. do you see any issue with doing that? you would need (or have electrician add) a gang box somewhere near the light switch or outlet above the vanity, run a piece of 14-2 cable from that box to another gang box inside the vanity, and then put an outlet into that lower gang box. the switch or motion sensor goes into the new box above the vanity, the pump plugs into the outlet below the vanity, power is provided when you flip the switch or motion is detected. do you see any issues with adding the wire or these gang boxes?
this type of pump system will not cost much to run and actually saves water. most people with this problem just run their shower for 5 minutes, dumping good water down the drain waiting for hot water to flow. This system just moves water around in the pipes, no water wasted. The delta cost is literally the cost to run the pump for 5-7 minutes per day (or eveythime you use the shower).
If this can work for you, the cost to install is not too bad. I think the pump system ran around 175 dollars and then you need to pay an electrician to add the switched outlet - maybe another 200 or so. If DH is handy, then cost is less.
Where in the country do you live? Here in cent. Fl, using a heat recovery unit on your cent. A/C lowers your electric bill by at least $50 a month for a one-time cost of