Life with a Sense home energy monitor: More devices, real savings

Sense home energy monitor screenshot
© Sense

I knew that real-time data on our energy use would be interesting. But I wasn't sure how much it would actually save us.

We have all LED and/or CFL lights. Our appliances are all energy star. And I am a little bit of a nerd about going around turning out lights and switching off appliances. I am not saying this not to bolster my tree hugging credentials—our energy bills are actually quite high thanks to an old leaky house and two plug-in cars. Rather, I'm trying to explain why, even though I was excited about installing a Sense home energy monitor, I wasn't sure how much we would actually save.

After all, the same people who get interested about real-time data on their energy use are probably the same people who annoy the heck out of their kids by nagging them to turn out the lights...

It turns out, however, that I was nowhere near as perfect as I imagined. I mentioned this briefly in my January update, but as the screenshot above shows, simply turning off one appliance (an old, inefficient dehumidifier we had pretty much forgotten about) slashed the energy costs being recorded as "Always On" from around $1 a day to around 23 cents. The data folks at Sense—who have been very keen to receive feedback and keep on learning—were kind enough to take a look at the underlying data. Here's what they reported:

"We did have a look and your suspicions are right. The dehumidifier did it. This plot shows you the point of change and how the baseline wattage drops on Dec 17. It drops from around 500 to 100 W. Your dehumidifier was actually using ~ 360W all the time --> 0.36kWh --> 8.6kWh/day --> assuming 10cents /kWh --> 86cents / day which is pretty close to the drop you saw."

While they are yet to show up on my energy bill (we have a flat rate bill due to massive summer spikes), these savings are likely to add up fast and, if similar savings were achieved by others, they would easily pay for the cost of the monitor within a year or two. Of course, I could have simply walked around checking for appliances that had been left on—but Sense provided both the impetus to do so, and some actual data about whether it was worth the effort.

In other news, Sense has also gotten considerably better at identifying appliances and devices. The current list of devices identified—either directly by Sense, or with some renaming/detective work from me—include the dishwasher, dryer, furnace, garbage disposal, a hairdryer, a water heater, toaster, vacuum cleaner, our basement and oven lights, and even the coffee grinder too. Digging deeper into the settings, it tells me it's also detected a possible electric vehicle (which would make sense), but it's not yet ready to start displaying that data. (It might take it a while, I've taken to driving quite a lot less since I've seen how much my usage spikes when charging!)

What's interesting to me—although perhaps obvious—is that as more devices get detected, it also becomes easier to figure out what's left under "other" or "always on". The majority of our lights, our fridge, our washing machine and both cars are yet to be detected—for example—but each of these devices are used quite differently, so I can easily look for spikes in those categories to figure out roughly how much my car is using, for example.

True, Sense is certainly still learning and is far from infallible. I've still got a fair amount of mystery devices named "Heat 1" or "Device 2", etc. -- but many of these are relatively low consumption, so I'm not sweating too much about figuring out what they are. Which brings me to one more point: One of the unexpected benefits of installing Sense has been figuring out what NOT to worry about any more. Having been berated by tree hugging friends never to leave a phone charger plugged in, for example, I've done some playing around and now noticed that it's drawing less than a watt at any one time. Forgive me for my callousness, polar bears, but I really can't bring myself to prioritize this action. Unplugging my computer monitor, however, is a much more effective way to make a difference.

I'm still waiting to see exactly how much Sense can save me on my energy bills. Given that I recently installed a Nest Thermostat E upstairs, and also insulated our attic (more on that soon!), I am going to have a hard/impossible time isolating any specific savings. But Sense is still useful in that sense, allowing me to evaluate any changes we make and really dig down on whether they make sense. So far, our furnace appears to be drawing significantly less electrical power following the changes noted above. We'll have to see once the gas bills roll in how much the actual savings do turn out to be...

Disclosure: Sense provided their home energy monitor unit at no cost for this extended review. I covered installation costs myself.

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