The shower and hot water heater are far apart. So every time we want to use the shower at least 3 gallons of water go down. To save water I put a hot water circulation pump in with an eye towards it being energy efficient. The normal way they are used is they get installed on the hot water heater, a timer runs the pump potentially several hours a day. Well I don't like that. I want to keep hours off the pump so it lasts longer and I don't want to keep circulating hot water when it's not going to get used. So I installed the circulation pump near the bath room in an adjacent laundry room. Ran it on a timer and temperature switch. The timer runs the pump until the temp switch shuts it off, then the timer times out before the water in the line cools off. First problem, when the hot water is on it sucks cold water back through the pump and cools off the water. Not good. Fixed that by adding a flapper check valve. Second problem, when I open up the garden hose spigot it sucks hot water through the hot water line through the pump and check valve. Thats not very energy efficient. I ordered a big 120v 3/4'' solenoid valve. That should eliminate the unwanted hot and cold water mixing problem. Should save well over a thousand gallons of water per year and send semi warmed water back to the hot water heater instead of running it open loop and putting 3 gallons of cool ground water in the hot water heater.
Know a couple of people with propane hot water heaters and a long run who put electric hot water demand heaters in bathroom or kitchen. Used 220 volt ac systems and they heat up after less than a gallon, once the hot water reaches the demand heater, they pull no more juice, and an added benefit they heat the cooler water if you pull the propane heater down to less then the set heat. Don't seem to have added much to the cost of electricity and they were fairly cheap to install. Already had 220 lines for range in kitchen, not used, and for the dryer in the bathroom, which was used. Since the ground water temp here is in the 40's, the water in the pipes, at basement temp or higher, make the tank less heaters work out quite well.
Saving water in Clovis, NM probably is a big deal. Here, it runs out of the mountain on it's own, into a pair of 1500gal storage tanks located above the house. I draw it off the bottom of the tanks to use, or the excess runs off the top of the tanks down a separate line that feeds into my fish pond, which runs into another fish pond, which runs into a local creek and rivers down to the Gulf of Mexico. Use it or lose it.
I had this same problem , had to push water from one end of the house to the other . For my application , I had a closet behind my shower wall , I bought a 110 volt 12 gallon WH and wired it in and even put a switch on it so I can cut it on and off . almost instantly hot water flows to my shower . I put the switch on it because I can turn it off if I'm going out of town and be heating water that isn't going to get used . If it's dead cold water , It only takes 15-20 minutes to heat it up .
I conserve propane by switching the water heater to start and only the pilot runs . When I know I am going to be needing hot water I switch the heater to run and give it a half hour and it'a ready to go. Eventually I will have my solar water heater plumbed in and avoid the wasted gas altogether . Solar water heating is probably one of the simplest things one can build for them self, I didn't say cheap, I said simple . The savings is down the line much like solar except faster realized. If you have a big family with showers happening and laundry solar along with regular water heaters make a difference too. Preheating the water before the water heater can save 75% of the energy cost or more. I have a friend in the mountains the uses solar to supplement his heating during the winter and virtually it cost nothing to heat his home during the winter. One must use a heat exchanger in typical freezing environments and use anti freeze in the solar system but the temperatures are exchanged in the system, actual water never is exposed to the elements .
I have 4 solar Collectors for sale , Going to use Solar PV over collectors . Them are in Canuk land and I won't be moving them south , New owners can and get all the toys for a Sdeal . Sloth
I too have a long run from water heater to master bath. Haven’t done it yet but my plan is to run a water line that T’s into the hot water at the sink with a small pump and check valve and run it back to the water heater and T it into the heater’s cold water inlet. To control the pump have a motion sensor in the bath and temp sensor in hot water line at sink. When you walk into the bath, the motion will turn on power for the pump and if the water temp is below the threshold the pump runs circulating hot water until it gets warm. Not looking so much to save water (its cheap here) which would still be good but goal is to not have to wait so long for warm water. AT
Also any time I use the cold water it pulls water through the circulation pump and check valve. I need a solenoid and you may too. The 120v full flow 3/4 inch solenoid valve should be here Tuesday. I think it will save around 1,800 gallons per year. That is about 20 days worth of water.
It worked. Adding a solenoid shutdown unwanted flow through the circulation system. Using the garden hose spigot on the furthest end of the house from the water main does not pull hot water through the circulation system any more. It will if the circulation system is active. But the system is active maybe 5 to 10 minutes a day and once the circulation pump gets warm my temperature switch will shut down the flow with the solenoid valve .
