Smappee, why we designed it the way it is?

Smappee finds your appliances;  how does it work?

Smappee will find your appliances automatically after a few days of learning.  But it does not provide you the name and the type of the appliance.  There are hundreds of thousands of different appliances and manufacturers.  We do not have this database with all the signatures of those appliances (fridges, TV sets, ..) in order to let Smappee label the appliance automatically.

However what Smappee can do, is detect the different appliances that you have in your home, as they all have a different way to use the electric current.

A fridge for instance, has an electric motor to drive the compressor.  When the motor starts, from a standstill position, it will drain more power (thus current) during a fraction of a second, until the cooling fluid is circulating.  So let’s assume that your fridge, when starting to cool, uses 45 Watts of Power.  After a typical period of 5, 10, .. minutes, your fridge will have reached the 4°C setpoint and the motor will stop cooling.  The total power measured in your home ( being the total of all your appliances at that specific point in time), will then suddenly be reduced as your fridge just stopped cooling.  You would expect a reduction of 45 W (same as the initial power when starting), but in practice you will notice a reduction of a lower power, e.g. 40 W (as once the motor is running, it drains less power).  Smappee will match those power changes with statistical methods (eg. I see a +45W, then a -40W, again +45W then a -40W, etc.)  Of course it is more difficult than this, as ten’s of other equipments turn on and off in the meantime.  Or certain device of eg. 2000 W vary easily with 40W when draining their power.  So the difficulty is to match the power changes to the right appliance.  Many other difficulties include things like dimmers ( power goes from eg. 10W to 250W for the dimmed light), LED TV’s (depending on the movie you watch, power of the LED varies a lot!), ..


Still we have reached good performance and can detect and categorise “Loads” or “Appliances” that turn on and off.

I like to compare Smappee with Shazam, the App you would use to recognise a song you hear.  We all accept that in case their would be a lot of background noise or another audio source like speaking people or the radio, that the App would tell us, it did not recognise the melody.  Well in the case of Smappee, we constantly have background noise (chargers, standby consumption of devices, pumps, light, etc.) and multiple appliances being used simultaneously, i.e.  “singing their electric melody” all at the same time in the same “pub”. So when the “Bariton” sings (your dry washer of 3500W, ..),  it becomes hard to hear that little voice of your LED light (10W).

In other words, Smappee will listen to all the singing electric devices in your home (by measuring the the total power your home drains, thousands of times per second).  And it will recognise the different “melodies” (appliances), label them “Find me 1” (first appliance or “melody” found), “Find me 2”, etc.

The different melodies or appliances will be shown to the user once Smappee has heard them a number of times, so that it knows, it is not just random noise or a combination of other melodies.  This takes times, read a few “On and Off” events need to be heard or measured reliably before being presented to the user as “Smappee found a new Appliance:  Find me 12!”

As Smappee does not have that “big database” of all types of appliances and their “power usage footprint”, it is not possible to label the appliance it found.  Smappee will thus provide you a list of found “Find me XX” appliances, that you should label, i.e. find out what it is.

Finding the appliance “Find me 12” is an interesting excercise,  at least if you really want to understand your home’s energy footprint, or understand how much power and energy the fridge or the microwave will drain.  Actually it’s also fun to do, just like an energy management game.

How well does it work?

I hope you will understand how difficult it will be for Smappee to identify the different appliances in your home, and that sometimes, when multiple appliances turn on or off at the same time, it could miss that event of: “Fridge turned On”.

The first thousands of Smappee devices installed in the field provided us so much useful feedback, that we were able to fine tune and really enhance that complex quest for appliances.

In my house, Smappee found over 70 appliances, I labeled them almost all and most of them are really detected for 99%.  I can verify the number of Nespresso’s we have consumed and I am ready to bet that Smappee’s count of “Nespresso ON/OFFs this last month” will perfectly match the number of Nespresso capsules I consumed.IMG_0002

The same for my “Garage door Open/Close” , the Light’s in the Garage,  the Spotlight in the garden, etc.

Energy consumption of these appliances?

As Smappee detects the Power (at ON and OFF event) and also registers the ON and OFF timestamps, it can accumulate the ON time (hours) and thus with the Power in Watts provide the Watt x hours consumed per Appliance.  Energy is measured in Wh or kWh (kilo Watt hours).

The DNA of a appliance

In order to provide more information on an Appliance, whether you have found it or not, the DNA will show you averaged data on how you use that specific appliance.  The DNA shows the number of times the Appliances turned ON and OFF, how long the appliance was ON in seconds (averaged over all accumulated ON-OFF cycles measured ever), the average Power (an average of the ON and OFF) used by that appliance in W, the total energy consumed per day in Wh and the associated cost ( Wh x cost per kWh).  You can edit your cost per kWh to match your energy supplier’s bill.

The list of key parameters ( Power, Consumptions, ..) is also provide on a per Week, per Month and per Year basis.  The per Year basis will be an extrapolation based on the “so far available data as collected by Smappee”.  If Smappee is in use for 5 weeks, it will use the “5 weeks” usage to estimate your annual consumption.

In order to further help the user to identify the appliance or understand when that appliance is in use, the DNA wheel shows you when that appliance is used, most of the time.  The darker the green segment, the more On and Off events have been found at that timestamp. A white segment indicates that the appliances has not been in use at that timestamp.

 The “Per Day” tab shows the wheel of the 24 hours usage (averaged over the last x days); the “Per Week” tab shows the usage for each day of the week.  The “Month” tab shows the sliding window of the last 31 days and the “Year” tab indicates the monthly usage allowing to identify seasonality ( appliance uses energy in winter month, but not in summer, etc.)


I make 4 Expresso’s per day.  The Expresso machine uses 1.140 W and requires 36 seconds to make this expresso.  It runs 2 minutes 30 seconds per day and consumes 48 Wh per day, cost at 0,25 EUR per kWh is 0,01 EUR.  Looking at the outer circle on the DNA, I make coffee’s in the morning around 7h30 (darker segment there) and around 13h after lunch.  I also make coffee’s in the morning and afternoon (correct, I work home) but never at night, nor in the evening, except once at 1 am when we had friends coming over to our place.  Desert time!


On a yearly basis, I will drink 1359 coffees, consume 17 kWh to make them and this will cost me 4,34 EUR!.  It seems I drunk less coffees in July (lighter Green in the DNA image here above).  Correct, I was off on holiday. The month of May was incomplete (so lighter green).

Why did we use that principle called “NILM” in Smappee?

Nilm stands for “Non Intrusive Load Monitoring”.

Why did we implement this complex mechanism?  Could we not just simply measure each appliance in our house?

No !  You would never buy and install 70 (typical number of appliances) energy meters in your home.  The cost would be so high !  And it would not be practical either; would you really put a meter in the power socket behind your built-in fridge, and micro-wave.. ? And how would you measure your “Garage door motor” that is directly wired to your fuse panel?  How much time would you invest in installing and reading those meters?

So our conclusion was that if we wanted to provide you, our customer,  a “workable” and “affordable” solution,  then that solution had to:

  • to measure as much as possible appliances with just one sensor!  (versus  50+ unpractical “power plug meters” everywhere..),
  • measure the total of your home (in order to verify your bill),
  • easy to install (one sensor and not +50)
  • affordable (thus one sensor, no additional display required, .. )
  • provide real-time feedback of your total consumption down to the level of your appliances (achieve 12% savings, see further)
  • user friendly software (App based, smart phone, table)
  • Smappee doesn’t come with yet another display, but makes use of your smart phone or tablet (cost reduction)
  • Real-time info, view your home’s appliances from anywhere
  • Be able to measure your solar energy production!
  • measure the Power and Energy as accurate, if not better, than the utility meter (means the Voltage needs to be measured as well, variations of 10% during the day are normal)
  • The solution should be so fun and bring more “added value” than just measuring energy, as that alone, is boring!  (We added remote control from anywhere, detect if appliances are on or off: someone home? A burglar or the kids well home. Forgott to turn off my iron? ..
  • Be future proof ( Smart Grids and demand response, electric vehicles ..), be part of the new IoT (Internet of Things) community of interoperable devices (IFFT, Apple Homekit, etc.)


    1. Bonjour Christian,
      Oui ça marche avec des panneaux solaires, mais Smappee devra les mesurés! Voir le “help center” sur et les sections “installation”. Vous y trouverez une explication détaillée, en anglais pour le moment. Traductions suivent une fois au point en anglais. Sorry et merci,
      Stefan G.



  1. Bonjour,
    On peux t’on acheté le systèmes ?
    Je suis soit a Bruxelles soit Namur.
    Bien à vous
    Thibaud L



      1. bonjour Stephan,
        il y a t il déjà une nouvelle version? si non quand est ce que elle sera dispo et quels sont les changement par rapport à la génération précédente?
        PS: combien de usagers effectifs avez vous déjà?


  2. bonjour Stephan,
    il y a t il déjà une nouvelle version? si non quand est ce que elle sera dispo et quels sont les changement par rapport à la génération précédente?
    PS: combien de usagers effectifs avez vous déjà?



  3. I am very impressed with the product. In about a week it detected all the “big energy consumers” at home with little effort. Regardless whether the product will pay itself back, simply having the insight into what is going on at home is amazing. And with the set of comfort plugs I bought I have a lot more control of the energy use. (e.g. laptops are usually charging day and night, about 10 minutes of charging every hour for no good reason !)

    Behavioural change will only happen for good reason, and with Smappee you find plenty of reason for changing things around the house !

    Now, since I started using Smappee I also gathered a list of 18 small or useful changes/improvements. Things that confused me, or things that would have helped, or things that would make it easier for my family to adapt. E.g. UI changes, or allowing 24h format, or another reporting view of the house, etc.

    Who could I send this list to ? I understand I won’t have a direct influence on the development of your product, but this kind of feedback may be useful to prioritize effort and/or get a view on how customers use your product.

    Liked by 1 person


    1. Hey Wieers, sorry for this late reply. I only update my blog a few times a year, (bad, I know!).. But I really liked your comment and input. I am in charge of product management, and your input went to the right person.. Some are known, and you know, it is a matter of priorities. There are so many things, ideas we want to add to make the product so much better. But we’re a limited team, with a lot of complexity. The hardware, the Apps on iOS, Android, and now also HTML / Web. With lots of countries from Australia, Brazil, North America, EU, UK, .. to the rest of the world. Support for languages, habits, etc. I promise we will make it better, suggestions welcomed! Just give us a bit of time. Thanks again.



      1. Thanks for your reply, Stefan.

        Now that I also have the Gas & Water smappee, I have some more ideas/features/bugs to send your way via support. Obviously I have no influence on priorities and feasibility…


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s