In one project the modules do not live apart: the heat loss calculation feeds pump sizing, underfloor heating and ventilation, and an accepted client form feeds all four. Nothing moves without asking - every time you see what comes in and what gets overwritten. This article describes the directions of flow, the module start screen, updates after changes in the source and what the import deliberately leaves out. What changed in the app in October: the October 2026 update.
Directions of flow
Data flows as a tree, always one way:
- the client form - to the heat loss calculation (building data and the room list), to pump sizing (building parameters), to underfloor heating (supply and return temperature, pipe), to ventilation (ventilation type, frost protection),
- the heat loss calculation - to pump sizing (building, rooms, heat loss), to underfloor heating (rooms with demand, temperature, type and storey), to ventilation (rooms with geometry).
Underfloor heating and ventilation write nothing back to the heat loss calculation. When a module has two sources, it offers the richer one first: for underfloor heating and ventilation the rooms from the heat loss calculation, for the pump the heat loss calculation.
Data from building documents read by the Algo assistant enters by another route - Algo proposes values straight into the module's fields, and you confirm them. That is described in Algo, the AI assistant. Algo can also read a whole building design and fill the heat loss calculation from it - rooms, building elements, windows and doors. How that works is in the heat loss calculation guide.
The module start screen
A module that has no data yet opens on a start screen with one violet "Start with Algo" button (in underfloor heating "Upload a plan") and the "I'll fill it in myself" link under it (in underfloor heating "Draw it myself"). The "Guide" link in the top-right corner, opposite the back arrow, opens the module's article in a new tab. In the heat loss calculation, pump sizing and ventilation, when the project has a ready source (a submitted client form, and in pump sizing and ventilation also a heat loss result), the screen has the same three presses with the import first: the violet "Import the heat loss calculation with Algo" (or "Import the client form with Algo"), the framed "Import without Algo" and the "I'll fill it in myself" link. Under them a grey line names the source and its three figures, e.g. "Heat loss calculation: 7 rooms · 142.5 m² heated · 8.4 kW load". The violet press enters the data, opens the wizard (on step 2 in the heat loss calculation, on step 1 in pump sizing and ventilation) and asks Algo what is still missing - in pump sizing Algo then asks only for what the calculation does not hold: the number of residents, whether the pump also heats hot water, and the client's tariff. "Import without Algo" enters the same data and opens the wizard without Algo. If you open Algo some other way (e.g. from the Algo column) on an empty heat loss calculation, pump sizing or ventilation module while the project has a ready source, Algo offers the import itself: it says the source is ready and puts the "Use the heat loss calculation" (or "Use the client form") press under its answer. If a second source is also available, an "Also available" line with that source and its figures sits below, with a "Use this instead" button. "I'll fill it in myself" skips the import.
When there is nothing to bring in, the line says why and links to where you can change that:
- "This project has no heat loss calculation yet" - the button leads to the heat loss calculation,
- "N rooms still need completing" - the heat loss calculation is unfinished; "Finish the heat loss calculation",
- "The heat loss calculation needs corrections" - it has blocking issues; "Open the heat loss calculation",
- "The client sent the form back - accept it to bring the data in" - the form awaits your acceptance,
- "The client has not sent the form back yet" - the form is with the client.
On a free account the line shows totals, and per-room loads are brought in the full version of the project.
Updates after changes in the source
When the source changes after an import (e.g. you add a room in the heat loss calculation), the module on the next entry shows the dialog "Heat loss calculation has changed" with the date of the previous import and a list of values: for fields it shows the current and the new value ("becomes"), for rooms the counts of new, changed and removed. Values you edited yourself are marked "edited" with the warning "Your value will be overwritten". You tick what to bring in ("Select all" / "Select none") and click "Bring in the ticked values". "Not now" postpones the question, and "Do not ask about this source" switches it off for this module.
You see the state of every source in the module settings under "Data sources": "up to date", "newer data available" or "declined", with the date of the last import and the "Bring in", "Bring in again" and "Restore" buttons (for a declined source). The "Clear data" button in a module also wipes the remembered imports, so after clearing, the start screen with the source lines comes back.
Pump sizing and the calculated heat loss
In pump sizing, the import ("Import the heat loss calculation with Algo" or "Import without Algo") enters the heated area and the rooms (name, area, temperature) and stores each room's load from the heat loss calculation. The sizing runs from that load, not from the insulation class. The wizard has its usual four steps and every field stays editable. The "Building" step then has no insulation class, ventilation type or room height - they are already in the calculated heat loss, and you change them in the heat loss calculation. Bringing data in only adds: rooms added by hand stay, and the radiators and underfloor heating entered in the rooms from the calculation do not disappear - only the name, area and temperature are overwritten. After changes in the heat loss calculation the same "Heat loss calculation has changed" dialog works as in the other modules. If the pump already holds your own data, bringing the calculation in from the module settings ("Data sources") first asks "Bring in the heat loss data?": the heated floor area changes to the one from the heat loss calculation, and its rooms join the list. A finished heat loss calculation the pump has not taken yet shows as a number on the module settings gear; when the calculation is missing, unfinished or has errors, its row says why.
Older projects in which the pump was linked to the heat loss calculation permanently move to this way of working by themselves on first opening. If an older project has a different load stored than the current calculation, the module shows the "The calculated heat loss has changed" dialog with the "Use the current load" and "Leave it as it is" buttons. Details in the article on heat pump sizing.
Underfloor heating and rooms from the heat loss calculation
In underfloor heating the rooms from the heat loss calculation come with demand, temperature, type and storey; the storeys from the heat loss calculation are created by themselves. Room names follow the heat loss calculation: a name changed there changes in the underfloor heating too, unless you renamed that room by hand in the underfloor heating. After changes in the heat loss calculation the panel shows "The heat loss calculation has newer data". Bringing the data in again from there, or with "Bring in again" in the underfloor heating toolbar menu, first asks "Update data from the heat loss calculation?": the room data (name, heat demand, temperature, type) is overwritten with the heat loss results - names you edited by hand too - rooms without loops can be moved to the right storey, and rooms with drawn loops stay where they are. "Overwrite with heat loss data" confirms it, and cancelling changes nothing. Manual changes in the overwritten rooms cannot be restored.
The heat loss calculation and ventilation: consistency checks
Ventilation reads rooms from the heat loss calculation and writes nothing back. In turn, the heat loss calculation checks whether the losses agree with the designed ventilation: the ventilation type must be "Mechanical with heat recovery (MVHR)", the recovery efficiency assumed in the heat loss calculation is compared with the efficiency of the chosen unit, and the supply and extract in every room with the flows from the ventilation module. The heat loss calculation shows discrepancies as remarks with the values from both modules.
What the import deliberately leaves out
The import from the client form lists the skipped items with a reason - on the start screen, in a grey line above the picture. The most common:
- a window or door with no matching room,
- hybrid ventilation - no equivalent in the heat loss calculation,
- a supply temperature given for a mixed system (the form also lists radiators, so the value may not be the underfloor circuit's) or outside 20-55 °C,
- no usable temperature difference - neither supply nor return is imported,
- a pipe diameter not on the module's list,
- a cooker hood - the answer is about one room and the form does not say which,
- an open-combustion appliance - the form asks about an external air supply, the standard asks about drawing air from the room,
- declared air flows - ventilation derives them from the standard.
Everything skipped you enter in the module by hand.