My electric bills have been extremely high for the past year or so. We recently finished an entire basement, put in a heated pool, installed a year-round heated spa, bought (and sold) an electric car, and switched from a gas water tank to an electric on-demand water heater. There are many possibilities as to what's causing the increase, but far too much noise from everything happening at once to logic it out. There is also a possibility that I'm wasting power somewhere unnecessary, since by all my calculations we still shouldn't be using this much.

I have seen "home energy monitor" devices that hook up to the fuse panel. However, these are very expensive ($300-$500), and even more so once you factor in the cost of an electrician for installation ($100+). I've also seen varying reports of success with them.

Is there a way using more common or inexpensive tools to accomplish something similar? Some way to track usage by device or room at the fuse panel? Tracking individual outlets is not a solution as I expect the largest energy consumers are not plugged into standard outlets.

  • 3
    curious, if you have gas available, why did you choose electric for all those things?
    – agentp
    Apr 16, 2018 at 20:43
  • Nicholas, is this electric tankless water heater supplying hot water to the whole house? If so, I am amazed. Where is your house located? What is the temperature of the incoming cold water? What is the electric power rating of this water heater? Apr 16, 2018 at 22:49
  • 1
    I think you're looking at the cost of the home energy monitor upside-down. You are assuming if you buy one, then all your costs will remain exactly the same except you'll also be out the $400-600 for the monitor, so the final accounting will have you worse-off by a predictable amount of money: $400-600. That assumption is false. Apr 17, 2018 at 0:33
  • Talk to your electric company - they might provide that as part of their service in order to control peak demands. The gas company might also have such a service because they would like to be able to replace some things with gas. That heated pool and spa is a huge power consumer. You have invested in a lot of electric appliances - generally they come with an average annual usage indication. Given the amount you have invested and the fact you are alarmed at your utility bill $500 is not much compared what you have and will spend .
    – Ken
    Apr 17, 2018 at 7:22
  • @Harper Again wish I could give you PLUS 10 for such a sensible response. If the bill is that high that the complaint has risen to find a solution - the investment of $500 to find a solution is negligible. even if the op finds out the pool is sucking the juice the op can decide on Solar or some other more economical means.
    – Ken
    Apr 17, 2018 at 7:25

3 Answers 3


The low cost "plug-in" energy monitors are actually quite good, but are limited to devices that plug-in. As soon as you want to monitor devices that are hard-wired like your pool, spa, water heater and electric car charger, you are going to have to have something installed by a licensed electrician if you are uncomfortable with working on your household power system.

The clamp-on device shown will not show you "Power"(watts), it will only be able to show you Current, which is a COMPONENT of Power (W = V x A x Power Factor). For the devices that are only resistant heat, like your water heater and pool heater and spa heater, Power factor is 1, so you can safely estimate Power by assuming the Voltage and measuring the Current. But for the pump motors and the car charger, there will be Power Factor involved and you need specialized metering to read it correctly, otherwise you are just guessing.

A very INDIRECT way of determining consumption of any given device is to use your utility metering in the following way.

  1. learn how to read your utility meter. Most utilities will provide you with instructions, often on a web page.
  2. Turn EVERYTHING off in your entire house, EXCEPT the load you want to measure
  3. Record the Watt-Hours at the start, and again in exactly 1 hour. For the pool and spa, make sure you are doing this under the worst case scenarios; the pump is running, for example during the filter time frame, AND the heater is called for because the pool/spa cooled down. The same for the Spa. You can "force" this by turning them off for a few hours before hand (but check to see when your filter runs, often they are scheduled for off-peak hours). That energy (Watt-Hours) will give you a general idea of how much power you are using per hour of run time.
  4. In the case of your car charger, do the same; plug it in and turn it on when you know that the car needs charging.

Unfortunately, you will not necessarily know exactly how many HOURS per day these things actually run. That's where a sub-metering system comes in handy. It will record the actual Watt-Hours they use in a given time frame. that takes more sophistication, hence the added cost. There are by the way some companies in some areas that own this equipment and will perform an energy audit for you for a fee, likely less than the cost of buying the equipment. In some places, like mine in California, the utility will do that for you if you ask. might be worth checking into.


Yes: there are 'plug in' type of metere like this:outlet electric metre buy some and use it per appliance. Anyway first suspect are heating swvice like boiler, pool heater and spa. For pool heater and boiler I hope you went for a heat-pump device, so consumption is less than 1/3 of a standard resistive unit. A way if you have appliances hardwired are amperometric pliers:pinza amperometrica that have just to go around hot cables to measure power going trough.


An episode of the TV show "Ask This Old House" described a system for monitoring the energy usage of individual devices by installing a single detector on the house power line and using a lot of computer smarts.

It works by identifying the "noise" that each device imposes on the AC power waveform as it uses energy. It relies on an on-line library of characteristic noise waveforms, plus an ability to "learn" about new devices..

The developers formerly worked in computer voice recognition, voice-to-text conversion, and the like...

No info on cost or level of development...

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