Smart apartment: fewer trips, lower bills, fewer disputes with guests
A short-term rental works well when you don’t have to go there for every changeover, when the heating and air conditioning aren’t working for an empty apartment, and when you find out in time when something is wrong – a window left open, water leaking, more people inside than booked, or someone smoking. The goal isn’t to watch your guests, but to run the property responsibly and profitably. MindzenSmart handles all of this in one system: access, heating and cooling, occupancy, air quality and outdoor cameras – in a single app for one apartment, and in a shared operator overview for several.
Sound familiar?
- Every arrival means a key handover, and everyone who has ever stayed there knows the key box code.
- In the building next door, someone ripped off the key box, got into the empty apartment, partied all night – and by morning the TV had gone too.
- The air conditioning runs all day in the empty apartment because the guest forgot to switch it off in the morning – or the heating is on next to an open window.
- It was booked for two, but according to the neighbour there were eight of them – and you only found out after the complaint.
- Guests smoked in the “non-smoking” apartment; the cleaner reported it, but the evidence had evaporated.
- Water leaked under the washing machine for days; only the next guest noticed.
- Three apartments, five apps – and nobody knows which cleaner’s code is still valid.
Solutions
Access: a smart lock or smart handle instead of a key box
The problem Everyone who has ever stayed there knows the key box code – and the bigger problem is that the key box itself announces: here is a short-term rental that is usually empty. It happens that the box next to the intercom is ripped off in a few seconds with a crowbar or bolt cutters; the key inside – your own key – is used to open the apartment, a party is thrown, furniture is broken, and at the end anything worth taking is carried off. In that case the insurer examines whether the key was obtained by breaking in and whether it was kept properly; meanwhile the neighbours come looking for you, even though you’re not there. With a physical key, you also never see when it’s copied – and the cleaner and the guest get in with the same key.
How do we solve it? No more key outside the property: we fit a retrofittable smart lock or smart handle on the front door that gives each booking its own code – valid from the hour of arrival, expiring at check-out and revocable remotely at any time. There’s no key box on the façade, so there’s no target and no sign announcing that the apartment is empty. The cleaner and maintenance staff each use a separate code of their own, so the log shows who entered and when – and also if someone tried to get in between two bookings. Where the lock supports it, you get an alert after several wrong codes, and the smart lock works together with the front door’s opening sensor: if the door opens without a valid code – for example because it has been forced – you’re notified immediately, rather than the cleaner discovering it the next day. The lock opens even without internet, because the code lives locally, on the lock; the documented mechanical back-up opening stays in your hands, not in the stairwell. Where the booking system supports it, the guest code is created automatically and sent to the guest in a message.
What you get Self check-in even after midnight, without travelling there or handing over keys; no box on the wall that can be ripped off and that advertises both the apartment’s key and the fact that it’s empty; access that can be blocked instantly; and a log that shows who was in the apartment between two bookings – which also serves as evidence in case of damage or a dispute.
Heating and cooling that follow your bookings
The problem Guests don’t pay the utility bills, so they don’t save: they heat to 24 degrees with the window open, or the air conditioning runs for three days in an empty apartment.
How do we solve it? We fit smart control to the radiator valves, the boiler or the air conditioning, working to four rules: economy temperature on empty days and comfort temperature before arrival; it turns down when nobody is in the apartment; it stops when a window or balcony door is open; and if the air conditioning or heating runs continuously for longer than allowed, it resets to the default. Meanwhile, the guest can still adjust the temperature – within a reasonable range that you have allowed them. You can see everything from anywhere and override the settings.
What you get A measurably lower energy bill without guests arriving to a cold apartment – and no more weekends of heating with the window wide open.
Occupancy information: is anyone in, and roughly how many
The problem You don’t know whether the guest has really checked out or is still inside; whether two people are really sleeping in the apartment booked for two; or whether anyone was in the apartment between two bookings.
How do we solve it? Without cameras, from three sources of data: door openings, signals from radar (mmWave) presence sensors and the carbon dioxide level in the air. A radar presence sensor reacts not only to movement but also to a person being in the room: it detects even the tiny movements of breathing, so it also picks up a guest who is sleeping, reading or watching TV – whereas a conventional infrared motion detector assumes the room is empty after a few minutes. The CO₂ level rises with the number of people inside – depending on ventilation and the volume of air in the apartment – so in a “booked for two, eight people inside” situation it can flag a pattern suggesting unusually high occupancy – although it does not establish the exact number of people. We don’t store the data unnecessarily, and we record no images or sound.
Not a camera and not a sound recording: these are sensors that measure a state – whether anyone is inside, what the air is like – rather than watching the guest. The platforms prohibit indoor cameras and surveillance devices; they allow noise monitors in common areas, without sound recording and disclosed in the listing. We recommend disclosing the presence and air sensors in your listing too – we’ll help you write the text.
What you get You know when cleaning can start; you get an alert if occupancy suggests significantly more guests than booked; and the entry log gives you something to go on if a check-out is disputed or an unauthorised entry is suspected.
Outdoor cameras – with area monitoring
The problem You can’t see who comes and goes at the entrance, or who is using the courtyard or the pool – and you don’t know whether guests are climbing onto the roof, the neighbour’s terrace or a closed-off area.
How do we solve it? We install cameras exclusively outdoors – entrance, courtyard, parking, pool; never indoors, at the outdoor shower or at the sauna, because both the platforms’ rules and data protection law prohibit it. The camera recognises people and vehicles, notifies you immediately when someone enters a designated restricted area – roof, fence, closed-off terrace – and gives you usable images at night. The footage stays locally on your own recorder or, if that’s more convenient for you, goes straight to the cloud.
What you get You see who arrived and when; you know immediately if someone goes where they shouldn’t; and if there’s damage, there’s footage.
Detecting smoking and vaping – from air quality
The problem A non-smoking rule can’t be enforced if only the cleaner’s nose flags it afterwards – by then the evidence has gone, but the smell stays for the next guest.
How do we solve it? We place air quality sensors in the bedroom and the living room that recognise smoking and e-cigarettes from sudden rises in fine particles and volatile organic compounds; heated tobacco products produce hardly any particles, so detecting them is less reliable. A smoke detector only goes off with dense smoke and typically doesn’t pick these up. The system logs the event with a timestamp, and the guest can receive an automatic, polite message. The same sensor also tells you when the air in the apartment is stale – a sign it’s worth airing it before arrival.
What you get An immediate alert and a documented event that your house rules and deposit terms can refer to – instead of a dispute after the fact.
Noise monitoring without sound recording
The problem You find out about the house party from the neighbour’s complaint – the next day, when the whole apartment building already knows.
How do we solve it? A noise monitor that measures only the volume and records no sound: if the level stays above the set threshold for a few minutes after 10 pm, the guest receives an automatic message first, then you do. Combined with the occupancy estimate, a pattern suggesting an unusually large number of people can trigger an alert the same evening – rather than only coming to light in the morning.
What you get Peaceful neighbours, keeping your apartment building’s approval, and a rule that guests take seriously because they know something will flag it.
Water damage and technical faults – before the next guest finds them
The problem Nobody goes into an empty apartment for days: a dripping washing machine, heating that has failed or an internet outage goes unnoticed until the next arrival.
How do we solve it? Water sensors at the critical points – washing machine, kitchen sink, water heater, bathroom – with an optional motorised shut-off valve that shuts off the water automatically if there’s a leak. Temperature, power and internet monitoring: if the apartment cools down, the power goes off or the router drops out, you’re notified – and know whom to send.
What you get The damage typically stops at a small amount of water, not at the ceiling of the neighbour below; and guests don’t arrive to a cold apartment or one without internet.
Country guesthouse with solar panels: hot water from the roof
The problem Most rural accommodation is a family house or guesthouse, increasingly with solar panels – and its biggest energy consumer is hot water. The water heater, however, heats whenever its thermostat decides: at dawn, after the guests have showered, using grid electricity, while at midday the solar output is fed into the grid. The same goes for air conditioners: guests switch them on in the evening, when there’s no longer any generation.
How do we solve it? We link hot water production to the solar system: the water heater – or heat pump water heater – heats when, and as much as, the roof produces a surplus. We align all of this with your bookings: a full tank by the evening of arrival day, economy temperature on empty days, with periodic heating above 60 °C to protect against legionella – and a mixing valve against scalding. If the house has several showers, we raise the tank to a higher temperature during the day so there’s enough in the evening too. The air conditioning pre-cools the rooms using the afternoon generation before arrival, and electric heating or the sauna also get time windows that follow generation; where there’s a battery as well, consumption after dinner also runs on your own power. All of this is controlled by the same local hub that manages the lock, the heating and occupancy. The water heater’s heating element can typically be connected without replacing it, while a heat pump water heater needs an SG-Ready or manufacturer control input – we check this during the site survey. The solar system and the battery are built or extended by our solar partner; metering and control are our job.
What you get Hot water and cooling mostly from your own generation – lower utility bills without compromising guest comfort. A nice figure on the screen shows how much the roof saved you this week.
EV charger at the guesthouse: guests charge, and you can bill for it
The problem Guests arriving by electric car check before booking whether they can charge at the accommodation – especially in the countryside, where the nearest public charger is twenty kilometres away. But anyone who has already put in a charger has usually faced the other side of it: a guest can put 60–80 kWh into their car overnight – and it shows up on your electricity bill. A car charging from a socket also loads the house’s supply for hours, unchecked – just when the water heater and the hob are working too.
How do we solve it? We install a wallbox sized to the house’s supply, with dynamic load management: the charger only draws as much power as the house is leaving free at the time, so the main fuse doesn’t trip because of charging, and you typically don’t need to apply for a capacity upgrade. Charging can be tied to the guest – by card, by a code assigned to the room number or started from the guest’s phone – and the system measures in kWh how much they charged. From there, there are two routes, and we can set up both. Prepaid amount: when booking or on arrival, the guest buys a set kWh allowance, for example 20 kilowatt-hours for one night; the charger stops automatically when the allowance runs out, with no calculating or arguing afterwards. Billing afterwards: charging runs freely, the system totals consumption per guest, and you can bill it together with the accommodation fee at check-out – with a MID-certified meter in the charger so the kWh figure is indisputable. It’s worth discussing the tax and legal side of reselling charging with your accountant. Guests can also charge for free up to a set allowance and pay above it – attractive in your listing, without leaving your electricity bill wide open.
What you get A line in your listing – “EV charging on site” – that makes electric car drivers choose you specifically; and a billing set-up in which charging isn’t your cost but an item on the invoice.
Several apartments on one interface
The problem With two apartments you can still keep it all in your head; with five you can’t: which cleaner’s code is still valid, in which apartment a window was left open, where a battery is running low.
How do we solve it? Every apartment gets the same set-up, with consistent naming and roles: you’re the administrator, and cleaners only see their own apartments and the functions they need to get in. Each apartment runs a local hub that works even without internet. The statuses feed into an operator overview that we tailor to your apartments at handover: a card for each apartment – occupied or empty, temperature, door, alarm – and a to-do list that collects battery replacements, open windows and fault alerts.
What you get One interface instead of five apps – and a system that expands in exactly the same way when you add a sixth apartment.
Why MindzenSmart?
- Security technology and smart home in one pair of hands. In Hungary, the professional, lawful installation of outdoor cameras and access control as a service is restricted to registered security companies, while heating and occupancy automation requires smart home expertise – we have both: one site survey, one point of responsibility. MindzenSmart (Mindzen Direct Kft.) is a security systems company registered with the Hungarian police.
- Local operation, not a subscription. The lock, the heating and the sensors do their job even without internet, the data doesn’t depend on a manufacturer’s cloud, and there’s no monthly fee just for the system to work.
- Proportionate data handling. We don’t install cameras or microphones in guest areas; what the system measures can be explained in one sentence in your guest information.
Frequently asked questions
Under Airbnb’s rules, can I put a camera in the apartment?
Not indoors – neither in guest areas (bedroom, living room, bathroom) nor in shared indoor spaces; both the platform and data protection rules prohibit it. Outdoors – entrance, courtyard, parking – you can place a camera under the platform’s rules if you disclose it in the listing and on site; in an apartment building, cameras in common areas also need the consent of the owners’ community. We only install in such places: we hand the system over with privacy masking and the necessary data protection documentation; we set the retention period on the recorder, and only designated persons can access the footage, with every access logged.
Why is a smart lock better than a key box?
A key box code rarely changes – anyone who knew it once still knows it later. A smart lock gives every guest their own expiring code that can be revoked instantly; the lock keeps a log and handles the cleaner’s access separately, and if a key is lost, there’s no need to change the lock.
Is the guest code created automatically for each booking?
For common booking systems and channel managers, yes: the guest receives their code in a message. Where there is no verified integration, we set up a reliable operator process that takes just a few clicks.
How does the system know how many people are in the apartment?
From door openings, radar presence sensors and the CO₂ level in the air – the latter rises with the number of people inside, depending on ventilation. The system doesn’t measure the headcount, nor does it prove a breach of contract on its own, but it can flag a pattern that suggests unusually high occupancy – without cameras or microphones.
Don’t Airbnb or Booking.com prohibit presence sensors?
The platforms prohibit indoor cameras and hidden surveillance devices. Airbnb explicitly allows noise monitors in common areas, without sound recording and when disclosed – but not in bedrooms or bathrooms. The rules say nothing specific about presence and air quality sensors; these measure a state rather than recording images or sound. We recommend disclosing them too in your listing and guest information – we’ll help you word it.
What’s the difference between a radar presence sensor and a motion detector?
A motion detector only reacts when someone moves: with a guest who is asleep or watching TV on the sofa, it assumes the room is empty after a few minutes, and the heating would follow suit. A radar (mmWave) presence sensor also detects the tiny movements of breathing, so it detects a person in the room even when they’re completely still, even asleep – which makes the occupancy information, and the heating and air conditioning control built on it, more accurate.
Does it really detect smoking, including heated tobacco products?
Cigarettes and e-cigarettes, typically yes: the air quality sensor watches for sudden changes in fine particles and volatile compounds. Heated tobacco products produce hardly any particles, so detecting them is unreliable. A conventional smoke detector only goes off with dense smoke and typically doesn’t react to these.
What happens if the internet is down when the guest arrives?
The code lives on the lock, not in the cloud, so the lock opens even without internet. Issuing codes remotely and sending notifications, however, do need a network; that’s why the system alerts you if the internet drops out, and the mechanical back-up opening remains in place at every apartment.
Can solar panels really provide the hot water at a country guesthouse?
In most cases, yes: the water heater or heat pump water heater heats from daytime generation, aligned with your bookings, so guests have hot water in the evening without grid electricity – on cloudy days the system switches back to the grid automatically. The existing water heater can usually be kept; the solar system and battery are built by our solar partner, and we add the control.
How do I bill guests for EV charging?
In two ways, depending on which suits your accommodation better. With a prepaid allowance, the guest buys a set amount of kWh and the charger stops when it runs out – no disputes afterwards. With billing afterwards, the system measures charging per guest, and at check-out you can bill the amount used together with the accommodation fee; if required, we install a charger with a MID-certified meter so the kWh figure is indisputable. The two can also be combined: free up to an allowance, paid above it.
Will everything be in one app if I have several apartments?
For one apartment, yes: the lock, heating, occupancy and sensors can be managed in a single app belonging to the local hub. For several apartments, though, the right answer isn’t one app but an operator overview: each apartment runs on a local hub – which works even without internet – and the statuses feed into a view we put together, with a card for each apartment and a to-do list, by role for the cleaner and for you. We create the overview at handover and keep it up to date under the maintenance contract. Charging billing and camera footage management stay on their own certified and logged interfaces respectively.
Does booking-based heating reduce utility bills?
Yes, because it doesn’t heat on empty days or next to an open window, and it turns down air conditioning that has been running for a long time. The exact saving depends on the apartment, the occupancy rate and the type of heating – we give you a realistic estimate during the site survey.
