Since 2020 or so, most UK homes have picked up a smart meter, and with it an in-home display showing a single number that updates every few seconds: how much power the house is using right now. It is genuinely useful for about a fortnight — long enough to notice that the kettle spikes the reading and the fridge doesn’t — and then it goes quiet in a drawer, because a single whole-house total stops being actionable once the novelty wears off. It can’t tell you which appliance is behind a high bill, whether the immersion heater got left on overnight, or how much of the solar panels’ output the house is actually consuming rather than exporting for a few pence a unit.
That gap is what the products below are for. Some clip onto the meter tails and give a smarter whole-house picture with history and alerts; some clip onto individual circuit breakers in the consumer unit and show a genuine appliance-by-appliance breakdown; the cheapest just sit in a socket and tell you what one thing is costing to run. None of them fix anything by themselves — they’re diagnostic, not corrective. If what you actually want to know is why a house is expensive to heat rather than which plug is the culprit, that’s a different job, and an EPC assessment or retrofit assessment answers it properly rather than a gadget guessing at it.
Where a monitor does earn its keep: chasing down phantom loads, working out whether a home battery or extra solar panels would actually pay back, or settling an argument about which appliance is responsible for the bill going up. Here are the six I’d look at, and what each one can and can’t tell you.
The one I’d buy
Emporia Vue Gen 3 (16-Circuit Sensor Kit)
This is the only monitor here that answers the actual question — which circuit is using the power — rather than an aggregate guess. Sixteen clamp-on sensors fit around individual breakers in the consumer unit, each reporting its own real-time and historical use to the app, alongside the main incoming supply. It is the closest a homeowner gets to an itemised electricity bill.
Typically £190–£250
Check price on AmazonHow I judge a home energy monitor
Where it actually measures from. A sensor on the main tails sees the whole house as one number; a sensor on a single breaker sees that circuit only; a plug-in unit sees whatever is plugged into it. That placement sets the ceiling on what question the monitor can ever answer, whatever the app’s dashboard looks like.
A real breakdown, not a confident guess. Some whole-house monitors offer “appliance detection” from a single aggregate reading — software pattern-matching against a library of typical appliance signatures. It's a party trick more than a measurement. A meter that reports what a specific circuit is doing, because it's physically clamped to that circuit, is telling you something real.
Installation reality. A plug-in monitor is a five-minute job for anyone. A whole-house or circuit-level monitor means the consumer unit cover off with the supply live while sensors go round the tails or breakers — straightforward for a competent electrician, and not something to improvise if that's not you.
What happens after the free years run out. Several of these bundle cloud dashboard access into the purchase price for a fixed period, then expect a subscription. Worth knowing before assuming the app works forever on the number printed on the box.
Solar and export awareness. If there are panels on the roof, or might be, a monitor that only counts import is answering half the question. The better whole-house units measure both directions.
The comparison
| Model | Measures | Circuit-level | Typical price | Best for | |
|---|---|---|---|---|---|
| Emporia Vue Gen 3 (16-Circuit) | Consumer unit branches + main | Yes, up to 16 | ~£190–£250 | Genuine appliance-by-appliance breakdown | View |
| Owl Intuition-lc | Whole house (meter tails) | No | ~£130–£160 | Established whole-house monitoring, 3-phase capable | View |
| Shelly EM Gen3 | Up to 2 circuits/CTs | Partial (2 channels) | ~£50–£65 | Solar export tracking and home automation | View |
| Efergy Elite Classic 4.0 | Whole house (meter tails) | No | ~£80–£100 | No wifi, no app dependency | View |
| TP-Link Tapo P110 | One plugged-in appliance | N/A — per socket | ~£9–£15 | Cheapest way to test a single appliance | View |
| Brennenstuhl PM 231 E | One plugged-in appliance | N/A — per socket | ~£15–£22 | No app at all, just a screen | View |
The picks in detail
Emporia Vue Gen 3 (16-Circuit Sensor Kit)
Best overall — the only genuine circuit-by-circuit breakdown here, and my top pick above
Emporia's Vue installs inside the consumer unit: a main sensor pair on the incoming tails, then up to sixteen 50A clamps around individual breakers, each reporting its own real-time use to the app at one-second resolution alongside a running estimate of cost. That is a fundamentally different proposition to a whole-house monitor guessing at appliances from a single aggregate signal — it knows the immersion heater is on because it’s clamped to the immersion heater's own breaker. It supports single-phase, split-phase and three-phase supplies, and handles solar/net metering if the sensors are placed accordingly.
The catch is installation: this lives inside a live consumer unit with the cover off, which is a job for a competent electrician rather than a confident amateur, and panels with only busbar access (no room to clip a sensor round an individual breaker's cable) need Emporia's flexible sensors instead of the standard rigid ones. It is also the most expensive monitor here by some margin. For anyone who has actually asked "which of my appliances is doing this" and wants a real answer rather than a plausible one, it is worth both the cost and the install.
For
- Genuine per-circuit readings, not pattern-matched guesses
- Up to sixteen circuits plus the main incoming supply
- Handles single, split-phase and three-phase installations
- 1-second data resolution, claimed ±1% accuracy
Against
- Fitting it means opening a live consumer unit — an electrician's job for most people
- The most expensive option on this list
- Busbar-only panels need extra flexible sensors, sold separately
Typically £190–£250
Check price on AmazonOwl Intuition-lc
Best established whole-house monitor — a name that's been doing this for over a decade
Owl clips a CT sensor round the meter tails rather than individual breakers, giving one live whole-house figure updated roughly every 12 seconds, with a cloud dashboard and phone app on top for historical graphs, peak-usage tracking and configurable tariff rates so it can estimate spend rather than just watts. The “lc” version specifically supports three-phase properties, reporting each phase separately — relevant to larger homes and some rural supplies. Two sensor sizes cover cables up to 200A.
What it doesn't do is tell you which appliance is responsible for a spike; it's a smarter, more permanent version of the free smart meter display rather than a diagnostic tool for individual circuits. The cloud dashboard is included for the first two years, after which Owl asks for a small ongoing subscription to keep using it — worth factoring into the real cost before buying.
For
- A well-established brand with a long track record in this category
- Handles three-phase supplies, reporting each phase individually
- Historical graphs and configurable tariff-based cost estimates
Against
- Whole-house only — no circuit or appliance breakdown
- Cloud dashboard access becomes a subscription after two years
Typically £130–£160
Check price on AmazonShelly EM Gen3
Best for solar and home automation — a proper two-way meter that plugs into a smart home setup
Shelly's approach is different again: a compact single-phase meter, wired into a standard back box rather than clamped externally, reading two independent channels — typically the incoming supply on one and solar generation or a specific circuit on the other. It measures import and export separately, which is exactly what's needed to see how much of a solar array's output is actually being used in the house versus sold back to the grid for a fraction of the price. It logs ten days of minute-by-minute data on the device itself, works over wifi with no separate hub, and includes a relay output that can switch a contactor — useful for automating an immersion heater to soak up excess solar rather than exporting it.
It needs a neutral wire at the installation point and is aimed at anyone already comfortable with home automation (Alexa, Google Home, or Home Assistant) rather than a plug-and-play whole-house dashboard. For a household with solar panels asking "is this actually worth having a battery," it answers the underlying question better than anything else on this list.
For
- Measures import and export separately — genuinely useful with solar
- Ten days of on-device data logging, no cloud dependency required
- Relay output for automating loads around solar generation
- No hub needed; integrates with Alexa, Google Home and Home Assistant
Against
- Only two channels — not a full circuit-by-circuit breakdown
- Wired installation, not a clip-and-go job
- Aimed at a technically confident household, not a plug-in dashboard
Typically £50–£65
Check price on AmazonEfergy Elite Classic 4.0
Best without an app or subscription — a standalone display, nothing more
Where Owl and Emporia lean on an app and a cloud account, the Elite Classic is a wireless CT clamp reporting straight to its own handheld display — no wifi, no login, no ongoing dependency on a manufacturer's server staying online. It shows real-time consumption and running cost against a user-set tariff, and that's the whole feature list. For anyone who wants the number on the fridge rather than in an app, that simplicity is the entire appeal, and it's genuinely one of the easier whole-house monitors to fit yourself, since the sensor is a clip-on clamp rather than something wired in.
The trade-off is exactly what you'd expect: no history beyond what the display itself can show, no phone access away from the house, and no circuit-level detail. It's a whole-house number, permanently, with nothing added on top.
For
- No wifi, no app, no subscription risk
- Simple clip-on CT sensor, straightforward to fit
- Portable display can sit anywhere in the house
Against
- No remote access or long-term data logging
- Whole-house only, no appliance or circuit detail
Typically £80–£100
Check price on AmazonTP-Link Tapo P110
Best plug-in smart socket — cheapest way to answer "is it this one?"
Before spending £200 on a whole-board monitor, the Tapo P110 answers the single most common question for a fraction of the price: is this specific appliance the one costing money. Plug it inline, connect it to the Tapo app over wifi, and it logs that one socket's consumption by the hour, day and month, alongside the usual smart-plug scheduling and remote on/off. It works with Alexa and Google Assistant, and needs no hub.
It only ever sees the one socket it's plugged into, so it's no substitute for whole-house visibility — but for chasing down a specific suspect (a chest freezer, an old tumble dryer, an aquarium heater), it's the cheapest and least committal way to get a real answer before spending more.
For
- Genuinely cheap, no ongoing cost
- Five-minute setup, no electrician required
- Works with Alexa and Google Assistant
Against
- One socket only — no whole-house picture
- 13A/2990W maximum load, indoor use only
Typically £9–£15
Check price on AmazonBrennenstuhl PM 231 E
Best bare-bones budget — no app, no wifi, just a screen and a plug
The Brennenstuhl is the pre-smart-home version of the same idea as the Tapo: plug an appliance into it, read voltage, current, power and running cost straight off its own LCD screen. There's no app, no wifi, no account — just a number, which is exactly what some people want and is one less thing to set up or eventually stop supporting. It has two adjustable tariff rates for day and night electricity, and battery backup so it doesn't lose its running total in a power cut.
It's a genuinely useful tool for a one-off check — is the old freezer in the garage worth keeping, what does an electric heater actually cost per evening — without any ongoing commitment. It won't log history over time or notify a phone of anything; it just reads whatever is plugged into it, for as long as it stays plugged in.
For
- No app or account needed — reads straight off the screen
- Battery backup keeps the running total through a power cut
- Day/night tariff rates built in
Against
- No history, no remote access, no automation
- One socket only, same limit as any plug-in meter
Typically £15–£22
Check price on AmazonWhat actually matters — and what doesn’t
The free display already does more than people credit. If the question is just "how much power is the house using right now," the in-home display supplied with the smart meter, or the supplier's own app, already answers it at no extra cost. Buy hardware only to answer a question that display genuinely can't: which circuit, which appliance, or how much solar is being self-consumed.
CT clamp readings are for spotting patterns, not settling a bill dispute. Clamp-based monitors are accurate enough to compare one day against another, or confirm that something switched off when it should have. They are not calibrated, certified metering equipment, and shouldn't be treated as more precise than that.
Opening a live consumer unit is not a five-minute job. The clamps themselves don't touch a live conductor, but reaching the tails or individual breakers to fit them means the board is open with the supply live. Fine for a competent electrician as part of the same visit; not something to improvise for anyone who wouldn't otherwise take the CU cover off.
Check what happens after the free cloud years end. Owl's dashboard, and several similar products, bundle a couple of years of cloud access into the purchase price and then move to a subscription. That's a legitimate business model, but it changes the real lifetime cost of the cheaper-looking option.
A colour touchscreen is decoration, not measurement. The number that matters is what's actually being measured and from where — a nicer display on a whole-house-only reading is still only a whole-house reading.
None of this replaces proper diagnosis of a genuinely expensive house. A monitor will confirm a heating system runs for eleven hours a day; it won't tell you whether that's because the house is losing heat faster than it should, which is a fabric and ventilation question, not a metering one. That's what an EPC or retrofit assessment is for.
Questions I get asked
Will an energy monitor actually save me money? Only indirectly, and only if something changes because of what it shows. Visibility alone nudges most households towards modestly lower use, but the real savings come from acting on a specific finding — an immersion heater left on, a fridge freezer that's failing and drawing more than it should, an appliance nobody remembers is still plugged in. The monitor finds the problem; fixing it is a separate step.
Do I need a smart meter to use one of these? No. Every product here except the free supplier in-home display works independently of the meter type, because the CT clamps and plug-in meters measure the electricity directly rather than reading data from the meter itself. A smart meter is only relevant if you're relying on its own free display or a companion app that reads its data.
Can I fit a whole-house monitor myself? A plug-in monitor, yes, in minutes. A clamp-based whole-house or circuit-level monitor means opening the consumer unit with the supply live to reach the tails or breakers — straightforward for an electrician to add to an existing visit, and typically only a modest addition to the call-out, but not something to improvise without that confidence.
What's the real difference between a plug-in monitor and a clamp monitor? A plug-in monitor only ever sees whatever is plugged into that one socket — useful for testing a specific suspect appliance. A clamp monitor sees everything passing through the cable it's clipped to, which is either the whole house (clamped on the meter tails) or one circuit (clamped on an individual breaker), depending on where it's fitted.
A monitor is a diagnostic tool, not a fix — if what it turns up points at the house itself rather than one appliance, an EPC assessment is the next step, or a full PAS 2035 retrofit assessment if the aim is to actually bring the bills down. If solar is part of the plan, what solar panels cost is worth reading alongside whatever a monitor like the Shelly EM turns up about current usage patterns, and what an EPC costs if it's been a while since the last one. Get in touch for a second opinion, and there are more field-kit guides if you're building out the rest of the list.
Small print. This guide is general information, not an assessment of your own property or electrical installation; any work inside a consumer unit should be carried out by a competent, registered electrician. Prices are indicative, move constantly and are checked at the time of writing; the linked page always shows the current price. As an Amazon Associate I earn from qualifying purchases.