The ventilation module designs mechanical ventilation with heat recovery for a detached house or a flat and checks it against PN-83/B-03430 with amendment Az3:2000. It is in beta - the badge "Module in beta - preliminary results" is a reminder to treat the results as preliminary. The wizard has six steps: Building, Rooms, Ducts, Unit, Modes, Result. Five of them are forms; the Ducts step is a drawing on the storeys' floor plans.
Before you start: data from the heat load calculation and the form
On entry the module offers to bring in the rooms from the heat load calculation (names, areas, heights, storeys) and one setting from the client form: the ventilation type and the frost protection. Ventilation only reads from the heat load calculation - it writes nothing back. The heat load calculation in turn checks consistency with ventilation: when the project has a designed ventilation system, the heat load must use mechanical ventilation with heat recovery, the same recovery efficiency and the same room flows; the heat load module shows discrepancies as remarks. Details in data flows between modules.
Step 1: Building
Two answers: the building kind (a detached house or a flat with its own unit) and the unit's frost protection (none, pre-heater, ground heat exchanger, supply throttling). Supply throttling unbalances the system while it runs; the standard allows in a flat with a fireplace, a solid-fuel stove or a gas water heater with gravity flue only natural or balanced ventilation, so in such a flat this strategy is not permitted and the module reports it.
Step 2: Rooms
Every room of the dwelling: kind (habitable room, kitchen, bathroom, WC, auxiliary room, laundry, stairwell, attic, technical room), area and height (enter the volume with sloped ceilings), number of people, number of doors from wet rooms. The system side (supply, extract, transfer) is proposed automatically from the room kind; you can override it. For transfer rooms you give the transfer opening (the standard requires at least 80 cm² in a room and 200 cm² in a wet room). A kitchen has extra fields: the cooker (gas, coal, electric, induction - the standard gives different flows), no external window, open-plan kitchen, hood. Other switches: a room on an upper level, a fireplace or combustion appliance, an active gravity duct.
You do not enter flows - the module computes them from these data. The rules of the standard it checks without a drawing: at least one supply room and one extract room, a windowless kitchen with a gas cooker must have mechanical extract, mechanical and natural ventilation are not combined in one dwelling, a hood is not connected to the heat recovery system, a garage or a boiler room is not connected to the dwelling's system.
Step 3: Ducts
You draw the duct network on the storeys' floor plans. Preparing a storey has four steps, led by the "Storey setup" panel:
- Upload the storey's plan - PNG, JPG or WEBP. Unlike underfloor heating, a PDF is not accepted here - save the PDF page as an image first. The ventilation plan is stored separately and never overwrites the underfloor heating plan.
- Set the scale (C) - two points a known distance apart and the distance in centimetres. Without a scale only panning works; the scale is per storey.
- Give the storey height - floor to floor of the storey above; the riser lengths are computed from it. In the same place you set the storey zone: heated or unheated (an unheated loft or cellar). The zone decides which ducts need insulating; while a storey has none, the panel says how many ducts are waiting on a storey zone.
- Line the storey up with its neighbour (G) - point at the same building point on both plans, e.g. a stair corner; the plan shifts so the points coincide. There is also a mode for dragging the plan by hand, with Shift to resize it.
Then you draw: "Place a point" (P) places the unit, a terminal, an intake, a discharge, a distribution box or a plenum box, with the system side (supply, extract, intake, discharge) chosen with the arrow next to the tool; "Draw a duct" (R) connects two points with bends along the way; "Draw a riser" (E) connects two storeys - the first click on this one, then you switch storey and click the other end; "Select" (V) opens the panel of a point or a duct.
You assign a terminal to a room from the list ("Pick a room"), not by its position on the plan - without an assignment its flow is not computed. The duct panel shows the length from the drawing (you can enter your own), elbows, flow, a diameter proposal from the flow and the target velocity (which can be overridden), and insulation (automatic from the storey zone: heated or unheated, with a manual override). The panel of a box and an intake has the "Coefficient Z" field - the local loss copied from the manufacturer's datasheet, with a button to enter it into every point of that kind; without it the system's resistances are not computed (an intake and a discharge without a value count as sharp-edged, Z = 1.0).
The storey-alignment findings say plainly what to fix: "This storey's plan and the one next to it overlap by only X %" - check this storey's offset and scale; "This storey's scale differs from the one next to it by a factor of N" - the reference distance was measured on a different drawing; "This riser's ends are X m apart in plan" - check how the storeys line up, or draw a horizontal run; "This riser crosses a storey with no height set" - give every storey on the riser's path a height.
Network rules: one unit on the drawing, ducts form a tree with no loops, supply and extract meet only at the unit, the intake and the discharge must be connected (without them the resistances come out too low), every point must have a path to the unit. Drawing needs a larger screen; the other wizard steps work on a phone.
Step 4: Unit
Two routes: "EPREL register" - you pick manufacturers (several at once) and the app fetches units from the European register with declared data (maximum and reference flow, recovery efficiency, fan power, sound power, energy class) and shows which will deliver the required flow; filters narrow by efficiency, power and noise. Or "From the DTR" - you copy the data from the documentation; such data is marked as not verified in the register. The register does not publish the fan curve, so in both cases you enter it from the datasheet: at least three points of flow and pressure, because a straight line between two points overstates the available pressure.
The unit verdict: whether it delivers the required flow, whether the operating point lies below the reference flow, and the pressure - a margin or a shortfall in pascals once the system's resistances are computed.
Step 5: Modes
You describe how the system works away from the design point: the nominal, reduced and boost modes, with the flow as a percentage of the design flow or in m³/h. "Add the three basic modes" creates the set. The standard allows reducing the flow only at night and at most to 60% of the value required for each room separately; a reduction in the daytime is not permitted. For the kitchen the standard recommends the option of a periodic increase in extract. Fewer than three modes is a remark, not a block.
Step 6: Result
The building's air balance: supply and extract, marking how much the standard requires and how much was added for balance. The room list with role, flow and the criterion that decided (table, people, air change rate) - a click shows the three candidates. Remarks with error and warning codes and the "Go to step" and "Show on the drawing" buttons. The unit section with the flow and pressure verdict, the catalogue efficiency and the efficiency assumed in the heat load calculation. "Commissioning" - settings for every terminal, to be done with an anemometer after installation. "Bill of materials" - generic types and quantities: ducts with lengths and diameters, insulation, terminals, boxes, intake, discharge, elbows, tees. From here you download the report ("Download the report") and the to-scale duct plan ("Duct layout") - see the article on reports.
Free account
On a free account you see the roles, required flows, balance and duct velocities. The resistances, pressure, unit verdict and printable duct plan are unlocked by a report, which covers the whole project - see what is free and what a report unlocks.