Hot Water Hero: On D’mand Pumps

Larry Aker

One Sky Homes projects never look the same, but we do tend to install a few products in every project.  One of these is the ACT D’mand re-circulating water pump, designed and built right here in California by the inimitable, Larry Aker.

Larry has been designing and building a very smart little device that primes the water pipes in your home to deliver hot water directly to your shower or sink as soon as you turn on the faucet.  It works by pressing a small button, just before you get in the shower or wash your hands at the sink.  This opens up a return loop to the cold water pipes and flushes the first draft of cold water back, sitting in your hot water pipes that typically we waste down the drain, back into the tank, so that only the hot water reaches us. 

We’ve now monitored the amount of energy this nifty gadget uses in our Sunnyvale remodel project, where our clients love not having to wait for hot water in their master bathroom - especially early in the morning.  From the daily and monthly graphs below, we measured average monthly energy consumption at just below 0.5kWh.  For non-energy geeks, this translates to an annual amount of <= 6kWh x $0.15 = $0.90 ...less than a buck a year!

We think Larry should receive some sort of hero award for his contribution to water and energy savings in California!  We’ll be sure to install one of these nifty devices in your project to make sure we can keep repeating Allen’s favorite Passive House mantra: “Hot showers and cold beers.” (Now with water and energy savings included!)

Daily Measure of On D'mand_SunnyvaleMonthly D'Mand











Images: L – daily measured energy use for the D’mand recirculating pump. R- Monthly measured energy use for the pump.  Above – Larry Aker of ACT and Bronwyn Barry of One Sky Homes.