Refoss Smart Home Energy Monitor with Open API, Home Assistant, No Cloud

I am extremely happy that I bought this Refoss Smart Energy Monitor EM16 to track the energy consumption in my home. I did a favor myself by watching a couple videos on youtube to make sure that this product meets all my needs and I can handle the installation comfortably and I HIGHLY RECOMMEND YOU DO THE SAME. Product is packed pretty well with all items you need (except screwdriver and some protective gear) and also comes with a user manual. User manual includes Installation guide with step-by-step instructions, Troubleshooting Guide, Technical specifications and Warranty. First, I have read the manual and all step-by-step instructions and then unboxed the rest of the items. I opened up my panel and took a picture and on a white paper I wrote down what breakers are connected to line A or to line B, that helped me to decide on connecting Lc to La as more breakers that I am planning to monitor are connected to line A. In your case, it may vary so make sure to look at the picture of your panel and plan accordingly to meet your energy monitoring needs. Refoss Smart Energy Monitor supports up to 16 channels and comes with 16 connectors excluding A1 and B1 (they go on to your service lines). I followed the instructions from the installation guide, and I felt it was pretty straight forward. Few of my breakers (A/C, Dryer and Range etc.) are 2 poles so I used both channels A and B and merged those channels (You may use one and change Circuit factor). Their app has a good feature where you can merge channels and label them (I have labeled them as A/C, Dryer etc.). Their app has a handful of settings that you can customize your setup based on your installation. To name some settings here, you can name each channel, merge channels, circuit factors (helps in case of using one circuit on multipole breakers), consumption alert etc. I don't have the Home Assistant set up so I can't say what functionality you get there. I wish they support other Smart home platforms, so it helps many users with their integrations (Smartthings etc.). About customer/technical support aspects, I had an opportunity to work with their support team as I noticed an issue, after the contact they asked me to share photos, and they suggested some changes to make sure that it is not an issue with the product. After completing the suggested changes, the issue still persisted and that helped them determine it was an issue with the monitor, and they sent a replacement and after installing the new one it worked flawless. Though their support is by email, they are pretty responsive and very helpful and knowledgeable. About the Product design aspects, it is well designed by keeping DIY installations in mind. Concept of using headphone-jack style and clamp style connectors is pretty easy to handle and helps with quick installation. After 4 weeks of monitoring, I can say that Refoss Smart Energy Monitor EM16 is pretty reliable to monitor energy consumption, and I highly recommend this product.

This is a Home Assistant specific review. If you are using the app and on a typical network, only #1 would be of interest. Overall it works great! It was easy to setup and integrate into home assistant. However there are a few things I did notice about it: 1. It has 3 sets of 6 channels and a voltage measurement for each. It does not work will if you have a single unit and want to measure an even number of circuits between 2 phases. (and by work I mean exact measurements. It will still be close) However I had 2 units so I was able to split the circuits and it worked out. For this I have to give it 4 stars as it does not easily support a typical split phase configuration. 2. It requires using their app and making an account for the initial setup and connection to wifi. The app will error out if your phone is on a different vlan than the wifi you selected but it still connects. 3. The unit requires internet access at least 1 time before working locally. 4. The home assistant integration that is officially supported automatically scans for devices and if it is on a different subnet, it will not be found. This can be solved by using the integration from HACS and entering an IP address. Overall I am happy with the device and that I do not need to flash custom firmware but still run it on an internet restricted VLAN with Home Assistant!

I love this. My only regret is that there's not one that can handle an entire panel with 42 breakers. If there was a bigger one, I would buy it instantly - great value. Especially once you realize that you have random energy usage spikes and use this to help diagnose it. I have this set up with home assistant and everything just works and flows perfectly into the energy dashboard. Getting it all set up both in the panel and on the wifi was a breeze. One note, if you connect the clip before plugging it in, make sure you don't touch the metal tip or you're in for a shock.

I’ve been using the Refoss Smart Energy Monitor for a week now, and I’m thoroughly impressed. One of the standout features is its local integration with Home Assistant, which is precisely why I chose this energy monitor. The instructions were straightforward, and the video on the Amazon listing was particularly helpful, guiding me through the entire installation process. It should be relatively easy for anyone with basic electrical knowledge and some handy skills. However, I recommend doing some pre-planning before installation to determine which circuits you want to monitor. There are five L1 circuit sensor, five L2 circuits sensor, and six circuits sensor that can be used on either L1 or L2. You’ll need to choose one or the other. Additionally, you can combine some circuits and use one clamp for them, as long as they don’t exceed the current limit of the circuit sensor. For instance, I combined two kitchen outlets into one, saving me a sensor I used for monitoring a different. For balanced 240V loads like an AC unit or an EV charger, you can use one clamp and then change the circuit factor to 2 in the Refoss app or create a helper in Home Assistant that multiplies the energy usage by 2. This is because with balanced loads, the energy drawn on both lines is the same, which is why it’s called a balanced load. This way, you can save a sensor to monitor another circuit. I highly recommend making a note of which sensors are connected to which circuits to avoid wasting time trying to remember where you connected them. Setting up the energy monitor on the app was a breeze. I simply downloaded the Refoss app, followed its instructions to connect it to Wi-Fi, and updated the software of the energy monitoring module. The Refoss app allows you to monitor live energy usage for each connected circuit and view a history of energy usage for each circuit, broken down by day, week, month, and year which is awesome for using the app on its own. Connecting to Home Assistant was equally easy. I searched for the Refoss add-on, and the energy monitor was automatically detected on my network. It brought over all the entities shown in the Refoss app and then I got to setting up everything in home assistant. Overall, I highly recommend this affordable and reliable whole-house energy monitoring system. If you use Home Assistant, this is one of the best options out there that is supported natively through the Refoss addon.

I installed an em16 pro in my home sub panel with the majority of my electric circuits. The install was fairly straight forward. I was able to get the connection to Home Assistant working with some difficulty. The integration for Refoss in the default repository is not correct for this version. After some back and forth with Refoss customer support I realized I needed to add the Refoss-Rpc integration. Once that was done on Home Assistant the Refoss device showed up immediately. The Refoss app is very basic and categorizes the panel input power as demand instead of supply from the grid. Customer supported told me this is an app bug and will be fixed in future firmware updates. Once I was connected to Home Assistant I was able to see clearly the power usage within the panel (both 120 & 240 circuits). Overall I'm very happy with the product and would purchase it again. In fact I have already bought a second unit for the main input panel on the side of the house. Looking forward to seeing dryer, hot water heater and garage usage. Customer support was very helpful and responses to my questions were overnight. This does require installation in your electrical panel. Please make sure you know what your doing and are careful. There's a ton of information on the net about how to do this. Mistakes though can be deadly...

Pros: - Build quality is on par with other competing products - Initial wifi setup is easy with no drama - Local LAN Home Assistant integration works decent Cons: - Manual makes references to "two phase" power, which is not a real thing. They should be saying "Split Phase". - Many configuration options are missing in the app, such as defining the sensor load as 120 or 240, which means after the fact you need to correct the load in watts based on your branch voltage (IE, double if it's 240) - Home Assistant integration does not allow any configuration or way to rename the sensors. - Sensor orientation is labeled BACKWARDS for Home Assistant - meaning, if you follow the manual, all sensors will report current draw as a negative number, and a positive value for backfeed (grid tie solar for example). This is the EXACT OPPOSITE logic employed with Home Assistant's energy metering. So if you follow the manual, Home Assistant will think each device is feeding back to the grid instead of drawing power. You'll either have to flip 18 current clamps to the opposite direction, or add inversion logic to each entity, which is annoying and messy. - Accuracy is a problem. There are 3 voltage sense wires, and the clamps are divided into 3 groups, A, B, and C. With single phase panels, this means you're measuring L1 + L2 and have to land the third wire on either leg. This means if you land the Group C sense wire on L2, if you use a Group C sensor on L1, you will get an incorrect voltage which is going to affect your measured load. A better way to do this is to be able to assign a sense wire - Current clamps are limited in size, and there's no option to buy larger clamps to accommodate large gauge wires for long runs.

Mostly does what it claims, if you read and understand the fine print. Overall, the install was about 2 hours, but there wasn't enough room in the bottom of the breaker panel for the box to fit. I ended up putting it near the top, but had to use a separate wifi antenna extension cable. Also, the instructions lead you to put the CT's on backwards. Other reviews mentioned getting them backwards, so I was super careful to follow the directions. All of the CT's reported negative values and needed to be flipped over. The meter has 18 CT's, but they are split over 3 phases. Since US consumer power is pretty much all 2 phase, this means you have to pick one of the 2 phases for your last set of 6 CT's. Basically, you get 6 CT's on one phase and 12 on the other, making actually using all 18 CT's really difficult. I ended up just prioritizing my 240V loads with this meter, and using zigbee smart plugs to measure 120V loads instead. There are a bunch of unused CT's still sitting in the box because I can't effectively use them to measure anything interesting. Power, voltage, and energy metrics all look reasonable (e.g. ~4600W on my hot water heater rated for 4500W), but current is often obviously wrong at low power draws. For example, it claims my heat pump is drawing ~32W at idle, but somehow also pulling 5A at 240V, which is just laughably wrong. I confirmed other people have the same issue by looking at their app screen shots. If you do the math, the numbers often don't add up. Higher loads seem better for some reason. I don't use the app (which seemed mediocre at best). I have a custom influx/grafana setup where I put all my other metrics, so I reverse engineered the Refoss Home Assistant integration off of github and wrote my own bit of software to poll the device via http (search for refoss_ha; userkey is "meross" by default). The protocol is vastly over complicated, but I did get it working. I had to hard reset the device multiple times, once by physically pulling the power because the reset button wasn't affective. I was also annoyed to find out recently that there is apparently an improved EM16P being launched "soon", which is supposed to make the software integration reasonable. Well, it's installed and technically working so I'm not going to rip it out, but that doesn't feel great.

I purchased this power monitor system specifically because it was advertised as a “No Cloud” system. My prior system stopped working when the company decided to shut down their cloud servers. I noticed that one reviewer said that this system actually did need the cloud to work, but what I found is that it needs internet access (to access a time server), but it didn’t try to contact any cloud servers as far as I could see. I found this out when I blocked it from accessing the internet at my firewall. When I did that, the system stopped working after a day or so. Once I looked at my firewall logs, I could see that it was trying to access a time server. Once I allowed it to access my DNS server, and a time (NTP) server, it started working again. Everything on the internet depends on DNS and NTP, so I’m not too concerned that these services will end anytime soon. I did notice that it was accessing a different NTP server about every hour, though. I thought this was odd, and they were all time servers I’ve never heard of. The system doesn’t use any of the popular NTP servers (NIST, ntp.org, etc). I also noticed that there was no provision to configure the NTP server in settings, so I created a “port forward” rule in my router that routes all NTP requests to an NTP server of my choice. The system has been working fine this way for a week or so now with no issues, and it’s blocked from accessing anything on the web except the time server I chose. Installation was about what you’d expect for this kind of system. You have to be comfortable working in your electrical panel to install it. If you don’t want to do that, you’ll have to get an electrician to install it. The hardware appears to be of good quality. None of it feels cheap, and pretty much everything is included that you’ll need. The software isn’t great, though. If you don’t use the app (and the cloud), you access it through it’s local web interface. There is real time data there, but you can’t really see any data older than about a half hour, making it pretty much useless. You’re supposed to be able to select day, week, month, etc., but that feature is buggy and doesn’t work. I ended up setting up a Home Assistant server. This took some time to figure out and get going, but it works much better than the native web interface. With Home Assistant, I can display power usage data on a graph, and move forward and backward in time as I please. The user interface isn’t perfect, but it’s much better than the native interface. Of course, you have to have an “always on” PC running Home Assistant somewhere on your local network for this to work. Over all I’m pleased with the system, although I think if you want a system that doesn’t depend on the cloud, it’s pretty much useless with only the native web interface. It only becomes useful when connected to a Home Assistant server, and that took a bit of tinkering to get going. You don’t have to be a total geek to do that, but it certainly helps.

I have been trying out the Refoss EM16 Smart Energy Monitor for a while now, and I must say, I'm impressed. It was easy to install—good instructions and helpful online videos meant the whole process was simple and quick. Took about an hour to have everything up and running, and all plugged in to the Refoss app successfully. I like best that this product is so versatile and thoughtful in design. You can just plan and label your circuits ahead of time, and if a clamp is showing up in the negative direction, you can simply reverse it in the app without the need to rewire. If you require additional circuits to be monitored, you can bus their wires together into a CT so long as they're on the same phase. The application is simple to operate, giving real-time monitoring of all the circuits, and detailed energy history by day, week, month, or year. Home Assistant support is where this product really shines. EM16 auto-commands and provides complete local access to all the data of each circuit, enabling advanced automation without the cloud. Solar system owners will love Zero Feed-In Automation—putting extra solar energy to use powering devices such as EV charging points or water heaters rather than returning it to the grid. The recent firmware releases saw the addition of various useful features, including channel merging, export of CSV data, improved dashboards, and inverting CT readings in software. The releases show that Refoss is refining the product according to feedback from users. Overall, the EM16 is a wonderful, budget-friendly energy monitoring system—easy to install, full of data, and ideal for smart home residents as well as anyone wishing to gain better control of and track their home energy usage. Highly recommended.

Having used this device for a few months, I finally feel comfortable writing my review. The product seems well designed, but lacks UL certification. I did get a bit of a shock when plugging in the Main sensors (A1 and B1), but after contacting support, I guess that can happen. I just need to be more careful. The app is helpful but it could be more intuitive. For example, the app doesn't let you keep a sort order of sensors and it can't send an alert if your amperage exceeds a certain level (which is my main interest). My hope was that I could use the sensor to ensure that I wasn't using my 100 AMP service above capacity and receive notifications if that was the case, but I've had to revise my expectations a bit. Overall the sensor is great and works well. I just wish it had some more features around notifications. Also, my electrical panel is pretty small, so I couldn't place the box inside the panel as the instructions indicated. However, it seems to be ok sitting outside of it. If you're looking for detailed information on what's using power in your house, this is good starting point.

I'm very happy with the EM 16. It does everything I was hoping it would. Install was easy. It took max 30 minutes once I got started. The app connected without issue. I installed all circuits as called out in the instructions but some circuits were showing negative power (as in energy flowing back to the grid) which was definitely not correct. I think that has more to do with my house but either way there are 2 ways to fix that. Either flip the clamp or set the power factor to -1 in the app which is essentially the same as physically flipping the clamp. The Home Assistant integration is great. There's almost no setup to connect it. The integration is native so when I added it to Home Assistant it connected itself to the EM16 without any additional inputs. Tips: - Install is really simple, power off to the whole house, connect the WiFi antenna, connect the power lead directly to a circuit, attached the clamps. - Do some planning before install. Consider which circuits should be monitored if you have more than 16. I wrote it out on excel first which made revisions before I started the install easy. It also made it easy to rename the circuits in the app after setup was complete - Mark the circuits you've planned on the breakers since the circuit numbers won't be visible when the panel cover is taken off. - There are 3 types of clamps, A, B, and C. A and B clamps need to be on different phases. C clamps need to adopt either the A phase or the B phase but they can't be on both. On North American panels, generally, each row of circuits (assuming the panel is oriented with the long edge vertically) is on a single phase. That means starting at the top of the panel and working down each row alternates phases. The photo with the panel cover is after the install. Apart from an antenna there’s no sign of the EM16.

After using this product for about 2 weeks, I can say that I'm very happy with it. It is easy to clip around your power cables, just make sure to have a multimeter or something to test that you are clipping at the correct one. (my installation had lots of colours mismatch). After installing, the Refoss app will automatically recognize it and install it, you will then be able to properly name your transformers and set a multiplier factor (i.e. negative if you clipped it reverted or a greater number if you ran out of transformers and want to estimate a double or triple phase). You can also give a estimated cost/kwh, set consumption alert per transformer, merge channels (i.e. 1 view for a 220v appliance were you clipped a transformer on both phases). I recommend it.

This device is easy to install , but as others have said you have to do some preplanning as to which ckts you are going to monitor as you are limited to which ct clamp can go onto which phase. There have been a number of users that complain that certain channels report negative values even though the ct's were installed properly. I have the same issue - 4 out of 16 were backwards. Not a big deal as it can be easily changed in the settings by changing the circuit factor to -1 , but this indicates very poor quality control by the manufacturer. WTF they had one job - 2 wires - its not rocket science. Another poor design feature is the size of strain relief connector for the wifi antenna - it is too small for a standard 1/2" knock out in the breaker box. You need to improvise with some sort of rubber gromet. I wish there was the ability to trend amps on each channel on a per minute basis so that I can monitor devices that cycle on and off. The only available graph trend is the total kwh value over an entire day - not much use for a motor that is only on for a few minutes. There is the possibility that when paired with Home Assistant you would be able to build your own trending graph, but I am not sure. Overall, I would recommend this monitor for basic power consumption trending and to see if some devices are using more power than you expected (ie older freezers and such). Only 4 stars because of the limited control you have over the graph/reports.