Prompted by a recent Sense Saves story, we’re conducting a small study to see how much energy hot water recirculating pumps are really wasting in peoples’ homes. If you have such a system, we’d love you to help us out by taking a survey. After you complete the survey, we may reach out directly (provided you give permission for us to look at your data) to do a deeper case study. This could involve turning off your recirculating system for a period of time, but in exchange we’d crunch the numbers on our end and give you some specific, actionable information on how to run your system more efficiently. In the end, we’ll be sure to share all of our findings publicly (private data redacted, of course).
I’m a little confused by the numbers in that original story.
My electric hot water tank is, as you’d expect (even in Dec/Jan with all-electric heat), the biggest watt hog on my panel and is averaging 34% of total consumption. The quoted numbers seem quite low for a whole-house electric water tank.
I don’t have a recirculating pump so can’t get involved in the survey but I assume what this is about is investigating the water (energy loss) aspect of recirculating and not the modest electrical usage of the recirculating pump itself?
In the example that prompted this survey isn’t it possible that the recirculation system is badly configured?
I thought no you may be correct for poor design.
I designed and installed my own. I think it is wash for costs as we use a lot less water now. The small amount of electricity is offset by the reduction in water.
They can use mine for the survey
It would, though you’re likely pretty energy efficient as is. It’d give us some good data to compare against though. if you have the time, definitely fill out the survey.
@RyanAtSense
I did fill out the survey several days ago. My Hot Water Heater average kWh was about 6kWh per day - or $0.76, First day after turning off the circulator was 2.5kWh or $0.30. Cut the usage by half so at this point I think I’m going to be waiting for the hot water to get to me! If the team wants to study this I can turn the pump back on if needed.
Just a thought but have you looked at intelligently controlling your circulator? Running it when nobody is home or late at night when everyone is in bed is a waste. If you added a smart home controller that could:
manage occupancy in your home
turn the pump off when nobody was there
turn the pump off at your normal bedtime
turn the pump back on at the time your alarm clock is scheduled for
I believe you could cut the cost significantly and not lose the convenience of instant hot water.
Just a thought.
I did all that a few months ago - you should have seen the numbers before! I had circulation from 5am to 8:30pm with a thermostatically controlled pump. We use very little hot water from late April until September as the city water is quite warm (Blame Arizona!) and cold showers aren’t cold!
i responded to the survey. i do have a smart recirc pump that learns your usage pattern for the week and then pumps ±1 hour when there is a demand for hot water for the following weeks.
the pump was discovered a while ago on one of my sense setups so i do have good amount of data. hope it will be useful to the team.
i have a large house and without a recirc pump i can get literally 3-5 minutes of cold water for the furthest shower thus my recirc pump water savings are significant. my average consumption is 3kwh per month at .24 cents per kwh
The red is when power to my pump is on. The pump only circulates is the temperature in the pipes drops by more than 10 degrees.
I ran a test with circulation off for a week and on for a week. It cost me about .1 KWH for the convenience. We are using 800 gallons less water a month now so it’s pretty much a wash. 72 KWH equals about $7.00 and 1000 gallons of water is $6.75.
It’s all in the design, components and usage setup.
Another shout-out to consider an on-demand hot water “recirculation” pump such as the chilipepper. I have used one for a few years now. Use is simple - press a button which starts the pump, then wait for the pump to stop - hot water is now available without additional waiting or wasting water. No need to have water circulating for an extended period (which basically turns your hot water heater into a forced hot water furnace). Simple to install, energy efficient, effective. I do not work for the company; just a happy user.
Thank you all who responded to this survey. We’re going to start digging through it very soon. You’ll hear from us directly if your data will be useful in this study.
