Energy Monitoring

Have you ever wondered which devices in your home are consuming the most electrical energy? Would you like to measure you power usage so you can verify that your utility bill is accurate? Is so, you might be interested in using or installing one of the many power monitoring devices now on the market.

These devices range from plug-in modules that are truly Do-It-Yourself, to more sophisticated devices that install inside your main electrical panel – definitely not DIY (the electrical panel is the metal box that contains switches called circuit-breakers. In most homes the panel is installed in the garage or a utility room.)

The Electrical Power an appliance consumes is measured in Watts. You’ll often see this abbreviated simply as “W”, for example a 200 Watts or 200W Refrigerator. When you receive an electric bill from your utility, how much you are charged will depend on how much Energy you have consumed over the last billing period. Energy is measured and billed by utilities in a unit called Kilowatt-Hours (abbreviated KWh): the energy an appliance uses depends on its power consumption, and how long it is drawing power.

On average in Florida, utilities charge around 12 cents per KWh (see a sample FPL bill here). Using our Refrigerator as an example, as it cycles off during the day, it might run for 6 hours a day, consuming 200W whenever it is on, so using about 1200 Watt-Hours of energy which is 1.2 KWh (costing around 14cents/day). Every electrical device in your home consumes power at different rates, and is on for different amounts of time. So tracking how your electricity is being consumed can be tricky without some help.

Technology has come to the rescue nowadays,and there are now several power monitoring devices available. In this post I’ll briefly describe a sampling of these devices, and the pros-and-cons of each. I’ll cover:

1. Plug in power monitoring devices
2. First generation, Full-Home (or business), panel mounted
3. State-of-the-art, Full-Home panel mounted device

Plug-In Power Monitoring

These devices plug into a receptacle and then the device you want to measure plugs into the device. Power flows from the receptacle through the device and out into your appliance. This means the device can directly measure the power consumed.

These devices have brand names such as “Kill A Watt”, and KMC. Remote access is sometimes provided using WiFi. In the case of the KMC devices you can even switch the outlet on and off remotely over WiFi.

Why the Plug-In Type is Good:

• Very affordable, at least to monitor a handful of devices
• Just plug in: you do not require a licensed Electrician to install

Problems with the Plug-In Type:

• Although each monitor is affordable, you need one monitor for every single appliance you want to monitor – the cost can add up quickly
• Because they plug into a standard wall receptacle you do not have visibility into lighting, nor do you have visibility into heavy duty 240V loads such as pool pumps
• It is next to impossible to use these devices to verify your utility bill since you only have a fraction of the data you need

1st Generation Panel-Mounted Energy Monitors

These Monitors install inside your Electrical Panel. All Electrical power in your home comes into and flows through the main panel (for some businesses and other special cases there may be more than one panel, but we’ll ignore that for now). Because you are installing the energy monitor in the panel, it can see the energy consumed by ALL electrical devices plugged into your electrical service. This means you are able to monitor devices such as lights, electric ranges and pool pumps that do not plug into standard receptacles.

These devices have brand names such as Eyedro EHEM1 and Neurio Home Energy Monitor. They are installed in your main Electric panel: the cover of the panel is removed, the device is placed inside and wired into an existing or new Breaker, and devices called Current Transformers are clamped around the main power feed.

WiFI connects the monitor to the internet where you can view it on a website.

Why the 1st Generation Panel Mounted Type is Good:

• Total visibility of all electrical power consumed in real-time
• Stores average data of power consumed over time that you can graph and download
• Can directly compare the data from these devices with that billed by your electric utility
• Some models work with Solar Power as well to monitor how well that is working
• Cost is initially higher but a single device can monitor everything you use

Problems with the 1st Generation Panel Mounted Type:

• Higher cost to acquire and will need a licensed electrician to install safely
• Provides good real time data, but you cannot – without some major detective work – figure out which devices are consuming power.

State-of-The Art Panel-Mounted Energy Monitor

This category is led by a product made by Sense.com. They make a product – simply called “Sense” – that installs in the exact same way as 1st Generation panel installed devices, in other words it installs inside your main electrical panel. It provides all the same data that the previous generation of devices generate. It sends data into the Cloud where you can access it from any browser from anywhere you have internet access.

Where Sense is different is that is able to infer – guess if you like – which devices are consuming power at any instant. Sense can tell you which devices are consuming power – previous generation devices can’t. Sense samples the electrical data at a very high rate. Algorithms match patterns in the sampled data to the way specific types of devices consume. Every type of electrical devices – TV’s, Refrigerators, Garage Doors etc. – draw power in specific ways that create a “signature”. Devices are identified by Sense using these signatures. For the curious, there is more information on the technology from the manufacturer here.

In practice, the device is not perfect, particularly when you first install it in your home. It learns device signatures with help from people who tell the Sense system which device came on when it cannot identify a signature. The good news is that, once Sense learns this signature, not only will it remember it for you, it can share this with other Sense users. In this way the Sense system is always learning.

You build a view of which devices are consuming energy on an individual basis. There are also some interesting side-effect: if Sense can detect when a garage door opener is activated, and you can see that on a web browser in your office, you can remotely monitor what is going on back at home!

Why the State-of-the-Art Panel Mounted Type is Good:

• Provides information on Which devices are consuming power when
• Total visibility of all electrical power consumed in real-time
• Stores average data of power consumed over time that you can graph and download
• Can directly compare the data from these devices with that billed by your electric utility
• Some models work with Solar Power as well to monitor how well that is working
• Cost is initially higher but a single device can monitor everything you use

Problems with the State-of-the-Art Panel Mounted Type:

• Higher cost to acquire and will need a licensed electrician to install safely

Conclusion

The desire to carefully monitor energy consumption is only going to increase. Energy costs will keep rising and we will all demand more efficient electrical devices. Devices such as the ones described in this article help provide visibility into energy usage for home or business owners. For devices that require a licensed electrician to install, United Electric will be happy to help, just contact us.