Refoss Smart Home Energy Monitor, Native Open API & Web UI (No Cloud Required), Real Time Electricity Usage Monitor, Power Consumption Meter Works with Home Assistant & MQTT, Solar Net Metering, ETL | Smart Home Energy Monitor

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 couldn’t be happier with the Refoss EM-16! I love having a smart home and I enjoy adding tech that makes our lives easier, is simple to use, and just makes sense. I shopped around for an energy monitoring system for a while and decided the Refoss EM16 was the way to go. This was the right choice! The installation was far simpler than I expected. The included headphone-jack style connectors made wiring a breeze — no tiny screws or fiddly clamps to deal with. I had read reviews that talked about the extra wire since these can’t be trimmed, but as you can see in the before and after photos of the breaker panel, the slack is easily manageable. Refoss labels all the clamps to make attaching clamps and connecting to the unit a breeze. I took my time to be cautious, and I was still able to hook everything up and have it running in two hours, without any special tools. The EM16’s connection to my WiFi is strong and it hasn’t dropped at all. Refoss gives you all you need to connect your power wires including the wire nuts and extra wire. I was extremely happy and slightly surprised to see how well the instructions are written and easy to follow; no missing words or “lost in translation” instances at all. To make your install fast and easy, plan out in advance what circuits you want to monitor. You can also use a single clamp across two wires (in the case of dual breaker circuits like A/C or hot water heater), allowing you to use more clamps to monitor more circuits. The app itself is outstanding. It guided me step-by-step through setup and immediately started giving me clear, real-time data. The interface is clean and intuitive, making it easy to see my usage at a glance and drill into details when I want to. You can set alerts and automations easily through the app. You can also plug in your price per kWh for power and the app will tell you what your current cost are (see pics). This even helped me to find I had two circuit breakers mislabeled and one isn’t even connected to anything! Our home is only 7 years old and that wasn’t found by two previous home inspections! Since I love home automation, integration with Home Assistant is important to me and the process with Refoss was seamless. Once connected, it showed up right away and has been rock-solid ever since. I can automate notifications, track energy trends, and even display the data on my dashboards with minimal extra effort. I even have automations to turn lights different colors when the clothes washer or dryer is done so we don’t forget to dry and fold them. Overall, the Refoss EM-16 is a fantastic product if you want reliable energy monitoring with minimal setup hassle and full smart-home integration. I only wish I had bought and installed this sooner! Highly recommended!

Have this product managing power usage in out house along with the Homeassistant management software. It took about 2 hours to plan out and install. While I was comfortable doing the work myself as an electrical engineer. I wouldn't recommend it for most DIY folks unless they are able to completely disconnect their main outside the house before the breaker box. Wifi connection worked great. VLAN automatically setup with no issues. Size was good for my breaker box, not sure if it would be as easy for an older or smaller box. Two issues I had, the install is a total mess of wires... it wasn't that easy to clean up. Wish there was a way to integrate current monitors into the breakers themselves. Second issue is the current readings were ALL backwards, despite following the directions to a T. Fortunately you can toggle this by adjusting your multiple from positive to negative in the app. Unfortunately thats annoying to do because of some android bugs making it hard to type "-" in their app? Look is ok if you don't mind the rats nest of orange wires in your breakerbox. Cost seems appropriate given the components included. Just wish they included another 5-10 breakouts to cover a full box, or at least the capacity to add them from an expansion kit. Kit should be durable and last for years with no major moving parts. Curious to see how well the plastic clips hold out over the years if I have to move it ever...

When I received this product, I was initially impressed by how solid it felt in my hand. It is heavy and feels extremely well-made. The provided instruction manual was intuitive and written in perfect English (based on experience, this is a HUGE plus). After cutting the main breaker that feeds my electrical panel, I was able to remove the panel cover and install the device in under an hour. I initially had a little trouble routing the wi-fi antenna, but finally decided to let it hang from the bottom of my box. In an installation with a surface-mounted panel, this would be much easier. My only issue with the installation was cosmetic. The wires running from the clamps to the device's brain use molded plugs and cannot be adjusted for length. It would be a neater installation if these cable lengths could be customized, but I consider this nitpicking, and it did not change my initial rating of the product. Since I had already installed the Refoss garage door controller at the house, I already had the application on my iPhone. Adding the power monitor was as easy as hitting the "+" in the app to add it to the dashboard. After a little configuration of my circuits, so that 240-volt breakers appeared as a single device, the installation was complete. The app was now showing me the power consumption of my monitored circuits in real-time. While the device works exactly as designed, and the installation went flawlessly, the app could provide me with clearer information. The real miss in the application is the inability to rename (or even add footnotes) to the circuits. If they could add this ability, it would make a huge difference. You should also be able to arrange the circuits in a custom order so that my mains could appear at the top of the app rather than being listed in alphabetical order. All in all, this is a great little device that will provide me with excellent insight into my power consumption at home, enabling me to make informed decisions about sizing a solar system in the future. It will also show me where I can reduce power usage when I need to look at installing an emergency generator.

I installed the REFOSS EM18 Energy Monitor a few days ago, and I’m very impressed with its capabilities and performance. What I Like: • Complete Monitoring Kit: The unit comes with a full array of current transformers (CTs) that allow you to track both total household electricity usage and individual circuits, such as a hot water heater or air conditioning system. • Real-Time Data on Your Phone: The REFOSS iOS app makes it easy to connect the unit to your Wi-Fi and view live energy usage at any time. • Clear and Detailed Installation Manual: The included written guide is thorough and well-translated, which is refreshing compared to some imported products. It explains most installation steps clearly, making the process much smoother. • Customizable Settings: The app offers numerous configuration options to adjust the data display so it matches your system accurately. Things to Be Aware Of: • You must be comfortable working inside a U.S. electrical panel and with circuit wiring. • Power to your entire home must be shut off during installation. • If you’re not experienced with electrical wiring inside a breaker panel, hire a qualified electrician — safety first. Areas for Improvement: • The manual could do a better job explaining how to fine-tune certain settings for optimal data display. • In panels with limited space and many breakers, the wiring can become cluttered. I plan to revisit my installation soon to improve cable routing for a more professional look. I will also attach some installation photos so other users can see what a real-world setup looks like. Overall, the REFOSS EM18 delivers excellent performance, flexible monitoring options, and a well-designed app — making it a great choice for anyone serious about tracking their energy usage.

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 grew up wiring houses for my father’s electrical contracting company, and I first saw early versions of energy monitors over a decade ago at an expo in Chicago. Back then, they were bulky, cost thousands, and often required an electrician just to interpret the data. Fast forward to today, and I’m amazed that Refoss has made this kind of professional-grade monitoring simple, affordable, and user-friendly. Installation was straightforward: hot wires to a breaker, neutral to the bus bar, antenna placed neatly — and that was it. Within minutes, I had real-time energy data on my phone through the Refoss app. You can connect the product directly to your wifi extremely easily and quickly. The dashboard is clean, intuitive, and gives you an instant breakdown of where your electricity dollars are going. The accuracy is outstanding. I’ve compared readings against other monitoring devices, and Refoss delivers precise, circuit-level data without the guesswork. Instead of bulky smart plugs or rough math, you get a clear, exact picture of your home’s consumption in real time. What really impressed me is how well it integrates with Home Assistant. That opens up endless automation possibilities: shutting off high-consumption devices during peak hours, getting alerts if a circuit suddenly spikes, or tracking trends over time. It’s flexible enough for advanced users, but simple enough for anyone to get value right away. Most importantly, it pays for itself quickly. By spotting just one hidden load — like an old lamp drawing $40 a month — the savings alone can cover the cost of the unit in under five months. After that, the insights are pure savings. Bottom line: this feels like professional equipment that’s finally available to homeowners at a reasonable price. If you want to understand your power usage and cut your bills, this is the tool you need. Knowledge is power — and this monitor gives you both.

I installed two Refoss EM16 energy monitors across two standard residential 200A GE split-phase panels. I have a 400A entey. The physical installation process is straightforward, and the included CT count is generous. The hardware itself appears capable, and the live branch circuit monitoring works well once the channels are labeled and organized. However, the app/setup experience has a serious issue with the 200A main CTs. The CTs were installed according to the manual’s K-to-L direction convention: on the mains, K is on the utility/meter side and L is on the panel/load side; on branch circuits, K is on the breaker side and L is toward the load. The voltage references were also matched to the correct panel legs. Despite that, both main CTs initially reported normal utility consumption as negative power/generation. This caused the monthly energy history to accumulate under the generation/export side instead of consumption. The only workaround I found was to change the channel factor for the main CTs from 1.00 to -1.00. Even that was unnecessarily difficult because the app keyboard showed no usable way to enter a negative sign. I had to copy “-1.00” from another app and paste it into the field. After doing that, the mains started reporting positive consumption correctly and the generation counter stopped increasing. (Android app on S26 Ultra) That tells me the hardware installation was not the issue. The problem appears to be an app/configuration design problem or a missing setup option for utility import versus generation/export behavior on the 200A CTs. This matters because historical weekly/monthly graphs may now show both false generation and real consumption, especially for users who discover the issue after several weeks or months. It also raises questions about how the app handles totalizers, merged channels, and room/home totals when both main CTs and branch CTs are being tracked. Pros: - Good hardware concept - Lots of included CTs - Branch circuit readings appear useful - Channel merge feature is helpful - Live readings update clearly once configured Cons: - Main CTs reported utility consumption as generation despite being installed according to the manual - No clear app setting for utility import vs generation/export - Negative channel factor is apparently supported, but the app input does not properly allow entering a negative value with the default numeric input keyboard - Historical data before correction appears polluted - Setup documentation does not adequately warn users about this issue (utility -vs- generation) Bottom line: The Refoss EM16 can be useful, but the app and setup logic need work. If your main CTs show negative watts or generation during normal utility consumption, check the channel factor. Setting the main CT channels to -1.00 may be required. Branch circuits should usually remain at 1.00. I would not recommend this product to a casual homeowner unless they are comfortable verifying phase mapping, CT direction, channel factors, and app totals. For technically capable users, it can work, but it should not require this much detective work. After correcting the main CT factors to -1.00, live consumption readings became correct, but the app did not repair historical data. The weekly/monthly graph continued showing the previous false utility usage as “generation,” which makes the reporting unreliable unless the device is reset or the bad period is ignored. I am glad I dug deeper only 1 week after installation, not 3 months. Who I am: Yes, I used AI to clean this review up. I used AI to assist with a deep dive into my installation to ensure correctness and user manual compliance BEFORE I drew attention away from the products positive aspects. I am not an "installer". I am not a "novice". I work with and design 1PH and 3PH power applications in my profession I do not fear electrical current, I respect it. That mentality will save your life.

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.

Overall a good product after monitoring for a few hours. The app could be more user friendly and organized a bit better. Like some others have said some sensors are wired backwards and will give you a negative value even if installed correctly but is easily overcome with the circuit factor. About half of mine were wired incorrectly. I wish the pig tails were a bit longer to give more options on where to mount the receiver but overall installation was very easy. So far so good, the product is giving me lots of information about energy consumption like it was designed to do. Would recommend

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.

I self installed this on my 200amp panel and it works very well. Installation was straightforward as long as you’re comfortable doing work inside the panel (make sure the power is off!). It’s been really useful to see where unexpected power draws are coming from, such as a heater in one of my adult children’s rooms that I did not know about! Recommended for all who enjoy having details of what’s happening in their house.

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.