For my use case, shutting off/turning on a water flow of to my heading system I can buy two different type of valves, mototed ball valves and solenoid valves. Most of the time the valve (either option) is not doing anything but is changed (open -> closed / closed -> open) maybe 4 times a day.

My question is about the (idle) energy consumption while there is not action happening. Does a solenoid not work by constantly iducing a magnetic field, hence consuming energy? Would a servo motored ball valve be better then, or is either case using energy in idle state (at least either for open or for closed?)

To give an example of a solenoid I have been looking at is this: https://www.amazon.co.uk/BACOENG-DC12V-Stainless-Electric-Solenoid/dp/B01054IED0

Suitable Media: Water Oil Air Valve Type:Direct Acting, Wet Armature
Operation Mode:Normally Closed
Plunger Tip:NBR
Working Pressure:0-1.0Mpa
Fluid Temperature: 23-176 F
Operating Viscosity: Under 20CST
Installation: Fluid direction should be as the arrow shows

  • \$\begingroup\$ If you use a latching solenoid valve, then it'll only consume power during the time that it's being opened or closed. \$\endgroup\$
    – EM Fields
    Commented Nov 19, 2016 at 10:34
  • \$\begingroup\$ Provide links to parts else otherwise remove the speculative aspects of the question. \$\endgroup\$
    – Andy aka
    Commented Nov 19, 2016 at 10:43
  • \$\begingroup\$ a quick google would have answered your question pneumadyne.com/solenoid-valves/… \$\endgroup\$ Commented Nov 19, 2016 at 10:57

1 Answer 1


If the device is a latching type that uses two coils or a single coil that is driven in a bipolar manner it could, in theory, use a solenoid and not consume energy when not being switched.

Generally solenoid valves do consume power continuously in one state, but you may be looking at some special type, we have no way of knowing.

There is another consideration- if the power fails, a normal solenoid valve will revert to a default state (say closed), whereas a motor-driven valve will retain the previous state. That can be a problem requiring system-level consideration such as backup batteries (and the related maintenance and charging system) just to ensure the valves can be returned to a safe state when the power fails.

Edit: the device you linked to is "normally closed", meaning it will draw power to keep it open. The data on this Chinese valve does not specify the coil power so you should contact the supplier and ask. It will typically be some watts. The "manufacturer" website throws a "may harm your computer" warning, so I am not looking further.

  • \$\begingroup\$ Since energy consumption is the interest, can you maybe qualify how much the power consumed in the one point is? Not necessarily linked to a special part, but relative to the power consumed while switching? Or is it that the power consumed during holding and switching is the same? thank you! \$\endgroup\$ Commented Nov 19, 2016 at 11:20
  • \$\begingroup\$ See edit. This kind of device draws X watts when open and nothing when close, there is no significant extra power drawn when switching. \$\endgroup\$ Commented Nov 19, 2016 at 11:36
  • \$\begingroup\$ found and linked the device from amazon, yet I agree that the information provided is insufficient. In general folks tends to give more often too little information. I (firefox user) also get the harm warning message, yet I see how much info I will reach not having javascript activated, thanks for your efforts and the information. Maybe for sake of completeness, the valves you mention (latching type) require extra special circuit to operate or can also go simple operate on voltage change? \$\endgroup\$ Commented Nov 19, 2016 at 11:52
  • \$\begingroup\$ Speculative. The datasheet will have the answers. Ask if you have a datasheet and have trouble interpreting it. \$\endgroup\$ Commented Nov 19, 2016 at 12:28
  • \$\begingroup\$ Up vote for pointing out a motorised and latching valve will not return to position on power failure. If this is ok then a latching or motorised valve is best for power consumption. Also to note, amount of power valve draws may not be the biggest consumer. \$\endgroup\$
    – KalleMP
    Commented Nov 19, 2016 at 22:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.