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Taking orders nowFinish the renovation: every room, the heating plant and the meters in one system
Insulation, new windows, a new substation, ventilation and solar panels make an apartment building efficient on paper. How much it saves in use depends on control. Bisly Wireless ties every radiator, the heating plant, the ventilation and the meters into one system, so the association can see and set the whole building and every owner pays for the heat they use. About 30 minutes per apartment, nothing drilled, and a return in under 3 years.
Energy efficiency first, with the smart home features that come with it.
A renovated panel apartment building.
Renovation sets the potential. Control decides how much of it the building keeps.
TalTech compared 2 identical four-storey apartment buildings in Tallinn after the same renovation: new windows, insulated facades and attic, a two-pipe heating system with room-level regulation, heat cost allocators and new radiators. One building cut its heat use by 52%, the other by 22%. In the second building the allocators showed apartments using up to 3 times as much heat as their neighbours, with no pattern behind it. The author's conclusion: there is more to save once the owners control their heating.
Panel housing estates like this one hold most of the region's apartments.
less heat after the same renovation in 2 identical Tallinn apartment buildings
average indoor temperature after renovation in 35 Estonian apartment buildings, so part of the saving goes into warmer rooms
measured heating energy against the design figure in an Estonian apartment building renovated to nearly zero-energy standard
Eligible for the grant, and still left out of the project
Building automation is an eligible cost in renovation grants. In Estonia the reconstruction grant covers automation works up to the apartment distribution boards. It is still rarely installed, for three reasons.
Cabled systems cost too much
Panel buildings were never built for control cables. A wired system means chasing walls in every apartment and stairwell, redecorating afterwards and sometimes moving residents out. In our comparison for a 60-apartment building, wired systems from the established vendors came to €120,000-160,000, with paybacks past 10 years.
Ordinary wireless does not get through
Reinforced-concrete panels absorb 63-70% of a 2.4 GHz signal, in a band already crowded by Wi-Fi, and off-the-shelf networks jam when hundreds of devices report at once. In our own test, a long-range network lost its signal one floor above the gateway.
Thermostats on their own save little
A smart radiator thermostat that works alone saves about 3%. It cannot ask the heating plant for less heat, so the substation runs as before and warm apartments leak heat to cold ones.
Thermostats save energy only when they work as one system
Bisly ties every radiator, the heating substation, the ventilation units, the solar panels and the meters into one system. The heating plant gets the real demand from every room, so it supplies only what the building needs.
Bisly Wireless: zones in the apartments, a wireless backbone, and the plant room as the only wired island.
Partial control saves single digits. The whole building saves 20% or more.
Room-by-room control does most of the work. Building management on top of it adds the rest.
A smart radiator thermostat on its own, with nothing above it.
Room-level control across whole district-heated apartment buildings, measured over 6 heating seasons.
The same buildings once the heating system was hydronically balanced as well.
Weather-forecast control of the heating saved 5-23% in 22 Polish prefabricated apartment buildings, and 13.4% on average in residential buildings in a separate long-term study.
Heating that follows residents' presence (geofencing) and learns how each apartment heats up saves up to 10% more than fixed, linear schedules. Certified learning thermostats must show at least 8% heating savings in field data.
Results vary by building.
What goes into each apartment, and into the building
In each apartment
- A wireless actuator on every radiator, measuring temperature and humidity
- A zone gateway, set up in about 15 minutes with the Installer App
- More sensors over Matter where wanted: CO₂, presence and Matter wall thermostats
- Window contacts that pause the radiator while the window is open
- Wireless heat and water meters
In the building
- A base station in the stairwell; every apartment strengthens the wireless mesh
- The substation, ventilation, heat pump and solar inverter connected through the integration module
- Remote-readable meters for billing
- The Bisly BMS for the association and the property manager
- Updates over the air
About 30 minutes per apartment. Nothing drilled, nothing broken.
Survey and digital twin
We model the building from its drawings: apartments, rooms, radiators, risers and plant. You get the scope and a fixed price within 5 working days.
Plant room and stairwell
The base station and the integration module go into the plant room and the stairwell, the only places with any wiring. The substation and ventilation keep running while they are connected.
Apartments
The installer swaps each radiator head for the wireless actuator and sets up the zone gateway with the Installer App: about 30 minutes per apartment, no drilling, no cables and no redecorating. Residents stay at home.
Live
Every device reports in before the installer leaves the apartment. The association gets the BMS, residents get the app, and the heating curve starts learning.
The association sets the rules. Every owner can adjust, and pays for what they use.
The apartment association decides the heating curves and the logic per room type: how warm bedrooms, living rooms and bathrooms are kept, the night set-back, and what happens when a window opens. Each owner can override within those limits.
A renovated apartment building.
Lower peaks make every kWh cheaper
A district-heating network is sized for the coldest days, and the peaks are covered by the most expensive boilers. When a building's heating runs under one control, it can shift its draw by an hour without residents noticing, which lowers the peak and with it the total cost per kWh.
Peak shaving
A cloud-based building control cut peak heat demand by 14-15% on average in 27 apartment buildings in Tampere, with 99.4% of indoor readings within half a degree of the setpoint. Heavy concrete buildings store heat well, and panel buildings are heavy.
Where power is billed as well as energy
Where district heating meters both energy and power, the saving counts twice. In Poland the ordered-capacity charge is 20-30% of the heating bill; in Finland capacity components are 10-50% of the annual cost. A lower, steadier peak lets the building order less capacity.
Baltic networks
Household heat in Tallinn, Riga and Vilnius is billed per MWh today, so the peak saving lowers the utility's cost first. Two-component pricing is expected in Estonia, and Bisly can follow the utility's demand-response signals when it comes.
After the retrofit: the whole building in one BMS, and an app for every resident
For the association and the manager
Bisly building automation and the BMS: every apartment, the substation, ventilation and meters on one screen, alarms by SMS and e-mail, and reports for the general meeting.
BMS and AdamFor residents
The Bisly app shows each room and the apartment's own consumption against last month, and sets a temperature or an away mode. Not needed for the basics: every radiator is still controlled on the actuator.
Smart home where wanted
The apartment network is Matter, so lights, blinds, plugs, leak sensors and door contacts can join later in apartments that want them. The retrofit itself is about energy.
Already renovated, or renovating now
Already renovated
The radiators, substation and ventilation are new, but there is no control layer. Bisly adds it without reopening a finished surface, and the first winter's data shows what the renovation should have delivered.
Being renovated
Add Bisly to the renovation project. On a renovated 40-apartment building it came to about 1.2% of the renovation budget, and it belongs in the grant application.
Renovation programmes already ask for it
Room-level control, hydronic balancing and metering are required or funded in most renovation programmes.
| Market | What the renovation programme says |
|---|---|
| Estonia | The apartment reconstruction grant requires heating regulated per apartment, thermostatic valves with limiters for 18-23 °C and a balancing protocol before payout. |
| Latvia | The ALTUM apartment programme funds individual heat metering, and heat meters and allocators must be remote-readable by 1 January 2027. |
| Lithuania | The modernisation call planned for late October 2026 adds 5 percentage points of support for modernising the substation and the heating system. |
| Germany | BEG "Efficiency Smart Home" funds 15% (20% with a renovation roadmap) of electronic radiator thermostats, allocators, energy management and wireless installations. |
| Poland | The BGK thermomodernisation premium covers 26% of the loan (31% with renewables), and heating upgrades qualify from a 10% saving. Heat metering must be remote-readable from 1 January 2027. |
Status 6 October 2026. Programmes change; check the conditions before applying.
What it returns
return on investment
less heat with room control and a balanced heating system, in measured apartment buildings
to install per apartment, with nothing drilled
Send us the drawings of one apartment building.
You get the scope and a fixed price within 5 working days, with the items that count towards your renovation grant marked.