The Refoss EM16 Smart Home Energy Monitor is a circuit-level electricity monitor designed to show where power is being used across your home rather than giving you only one total utility-meter reading.
The kit uses two large current-transformer clamps for the main electrical supply and sixteen smaller clamps for individual branch circuits. That lets you monitor both overall household consumption and selected loads such as HVAC equipment, kitchen circuits, water heaters, EV charging, pumps, or other high-use appliances.
The EM16 is also officially supported by Home Assistant, making it especially interesting for users who want household energy data inside a wider smart-home dashboard.
Check current Refoss EM16 pricing and availability on Amazon.
Refoss EM16 at a glance
| Feature | Refoss EM16 |
|---|---|
| Product type | Whole-home and circuit-level energy monitor |
| Model | EM16 |
| Main CT sensors | 2 × up to 200A |
| Branch CT sensors | 16 × up to 60A |
| Total monitored channels | Up to 18 CT measurements |
| Connectivity | 2.4 GHz Wi-Fi |
| Smart-home integration | Official Home Assistant support |
| Home Assistant requirement | EM16 firmware v3.1.7 or later |
| Measurements | Voltage, current, power, energy and related circuit data |
| Solar monitoring | Supported in the EM16 product configuration |
| Installation | CT clamps installed around electrical conductors |
What the Refoss EM16 is designed to do
The EM16 is designed to answer a question that a normal monthly electricity bill cannot: which parts of the house are actually using the power?
The two main sensors monitor overall household electricity flow, while the sixteen smaller sensors can be assigned to individual circuits.
That makes it possible to compare whole-home consumption with specific loads and identify which circuits are responsible for the largest share of electricity use.
Two main sensors and sixteen branch sensors
The EM16 kit is built around two different current-transformer sizes.
The two larger CT clamps are intended for the main electrical conductors and are rated for up to 200A each. Sixteen smaller CT clamps can monitor branch circuits at up to 60A each.
This configuration gives the EM16 considerably more circuit visibility than simpler monitors that track only total household consumption.
You do not necessarily need to monitor every circuit equally. The most useful approach is usually to assign branch sensors to the equipment whose consumption you most want to understand.
What can you monitor?
Depending on your electrical panel and circuit layout, useful candidates can include:
- air conditioning and heat pumps;
- water heaters;
- refrigerators and freezers;
- kitchen appliance circuits;
- EV chargers;
- pool or well pumps;
- laundry equipment;
- home-office circuits;
- solar production; and
- other high-consumption loads.
The value is not simply seeing a number. It is being able to compare individual loads and understand what is driving your overall electricity consumption.
Home Assistant integration
Home Assistant officially supports the Refoss Smart Energy Monitor EM16 from firmware version 3.1.7 onward.
The Refoss integration requires the EM16 and Home Assistant server to be on the same local network.
Once the integration is added, Home Assistant uses local-network discovery to find compatible Refoss devices.
For users already running Home Assistant, this is one of the EM16’s strongest advantages because circuit data can become part of a wider smart-home monitoring and automation system.
Why circuit-level monitoring matters
A whole-home electricity total tells you whether consumption is high or low, but it does not explain why.
Circuit-level monitoring can make patterns much easier to interpret.
For example, you may discover that:
- an HVAC circuit is using more energy than expected;
- a water heater is running for unusually long periods;
- an appliance consumes significant standby power;
- EV charging is dominating overnight electricity use; or
- a supposedly minor household circuit is contributing more than expected.
That information is more actionable than a single total household figure.
Real-time electricity monitoring
The EM16 is intended to provide ongoing visibility into electricity use rather than waiting for the utility bill at the end of the month.
The repaired QSL product source describes monitoring for voltage, current, active power, reactive power, energy and power factor.
This means the system is designed to provide more than simple accumulated kilowatt-hour totals.
Solar energy monitoring
The EM16 source material also identifies solar monitoring as part of the product’s intended use.
In a suitable installation, energy-monitoring clamps can be used to distinguish household consumption from electricity generated by a solar system.
This can help a homeowner understand how much self-generated energy is being produced and how closely household demand matches that production.
I would distinguish this carefully from the newer Refoss EM16P, which Refoss now markets with a substantially expanded local/Open API platform and newer solar automation features.
Refoss EM16 vs EM16P
The model distinction matters.
The EM16 reviewed here is the older Refoss Smart Energy Monitor.
Refoss now sells the newer EM16P, which is the model currently promoted around its newer local-first Open Platform features.
That means buyers should not assume that every EM16P feature is available on the original EM16.
If a retailer listing mentions MQTT, JSON-RPC, WebSockets, a built-in local Web UI or newer zero-feed-in automation, check the exact model and firmware before assuming those functions apply to the original EM16.
Installation
The EM16 uses clamp-on current transformers placed around electrical conductors.
The clamps themselves are non-invasive measuring devices, but installing them requires access inside an electrical panel.
That is not the same thing as plugging in a normal smart-home accessory.
If you are not qualified and comfortable working around a live electrical service panel, installation should be handled by a qualified electrician.
Planning your sixteen monitored circuits
Before installing the branch sensors, it is worth deciding which circuits will provide the most useful information.
A sensible priority is usually:
- major HVAC loads;
- water heating;
- large kitchen appliances;
- EV charging;
- pumps or other large motors;
- solar generation;
- laundry equipment; and
- other circuits where you suspect unusually high consumption.
This makes the available sensors more useful than simply attaching them to circuits in panel order.
Wi-Fi considerations
The repaired EM16 source identifies 2.4 GHz Wi-Fi connectivity and an external antenna.
That is useful because electrical panels can be difficult environments for wireless signals, particularly where the enclosure is metal or the panel is installed in a garage, basement, utility room, or exterior location.
Wi-Fi strength at the actual panel location matters more than signal strength elsewhere in the house.
What buyers commonly like
The existing product-source material shows several recurring positive themes:
- Detailed energy visibility: users can see more than overall household consumption.
- Many circuit sensors: sixteen branch CTs provide useful coverage.
- Home Assistant: integration is a strong reason to choose Refoss.
- Clamp installation: sensors do not require cutting the monitored conductors.
- Wi-Fi connectivity: the external antenna helps with panel placement.
What to consider before buying
- Electrical-panel installation: this is more involved than installing a plug-in smart device.
- Sensor cable management: sixteen branch sensors create a considerable amount of wiring inside or around the panel.
- Wi-Fi location matters: electrical panels can weaken wireless performance.
- Model confusion: EM16 and the newer EM16P are not the same product.
- Firmware matters: official Home Assistant support specifies EM16 firmware v3.1.7 or newer.
- Not an energy controller: the EM16 primarily measures electricity use; monitoring a circuit does not itself turn that circuit on or off.
Refoss EM16 vs a smart electrical panel
The EM16 and products such as the EcoFlow Smart Home Panel 3 address related energy questions but perform different jobs.
The Refoss EM16 is primarily an energy-monitoring system. It measures what the household and individual circuits are consuming.
A smart electrical panel can go further by actively controlling, prioritizing, or transferring loads as part of a backup-power system.
If you want a full smart electrical panel with broad circuit control, see our SPAN Smart Panel Review. If you want to keep your existing load center and add intelligent control to selected circuits, see our ABB ReliaHome Smart Panel Review. If you are considering whole-home backup within EcoFlow’s ecosystem, see the EcoFlow Smart Home Panel 3 review.
Who should buy the Refoss EM16?
The EM16 makes the most sense for homeowners who want detailed circuit-level energy visibility without replacing the electrical panel itself.
It is particularly attractive to Home Assistant users because the EM16 is officially supported by the platform.
It can also be useful for households with high electricity consumption, solar systems, EV charging, HVAC loads, or several large appliances where knowing exactly where electricity is going can help guide future efficiency decisions.
View the Refoss EM16 Smart Home Energy Monitor on Amazon.
Who should skip it?
Skip it if you only want a simple whole-home consumption total and do not need individual circuit data.
You should also consider a newer model if features such as the newer Refoss Open Platform, local Web UI, MQTT or more advanced solar-control functionality are central to your purchase decision.
Final verdict
The Refoss EM16 is most compelling as a high-channel-count household energy monitor with official Home Assistant support.
Its combination of two main CTs and sixteen branch sensors allows much more detailed energy analysis than a basic whole-home meter.
The main cautions are installation complexity, sensor-cable management and the need to distinguish the original EM16 from the newer EM16P.
For homeowners who want to understand exactly which circuits are driving their electricity use, the EM16 offers a useful level of visibility without requiring replacement of the entire electrical panel.
Frequently asked questions
What is the Refoss EM16?
The EM16 is a smart home energy monitor designed to measure whole-home electricity consumption and individual branch circuits using clamp-on current transformers.
How many circuits can the Refoss EM16 monitor?
The reviewed kit includes two main current-transformer sensors and sixteen smaller branch-circuit sensors.
Does the Refoss EM16 work with Home Assistant?
Yes. Home Assistant officially supports the Refoss Smart Energy Monitor EM16 from firmware version 3.1.7 onward.
Does Home Assistant control the EM16 through the cloud?
The official Home Assistant integration requires the EM16 and Home Assistant to be connected to the same local network and discovers compatible Refoss devices on that LAN.
Does the Refoss EM16 use Wi-Fi?
Yes. The EM16 product source identifies 2.4 GHz Wi-Fi connectivity.
Can the EM16 monitor solar generation?
The EM16 product source identifies solar monitoring as one of its supported use cases. Exact wiring depends on the electrical and solar configuration.
Is the Refoss EM16 the same as the EM16P?
No. The EM16P is a newer Refoss model with additional Open Platform and local-control features. Buyers should not assume EM16P specifications apply to the original EM16.
Does the EM16 control individual circuits?
The EM16 is primarily an electricity-monitoring product. It measures circuit behavior rather than functioning as a replacement smart electrical panel that switches or prioritizes household circuits.
Can I install the Refoss EM16 myself?
The CT sensors clamp around electrical conductors, but installation requires access inside an electrical panel. If you are not qualified to work safely in that environment, use a qualified electrician.