A room’s floor area is a useful starting point, but it does not determine its heating requirement. Two bedrooms of the same size can lose different amounts of heat. A sound choice starts with a description of the building, followed by a correct reading of the radiator’s technical data.
01
Describe more than floor area
Record length, width and height, then identify external walls, windows and adjoining unheated spaces. Add what is known about insulation. A photograph helps, but cannot replace these details.
State the project location and intended use too. Climate, exposure and desired comfort belong in the assessment. One universal figure in watts per square metre cannot represent all these situations.
02
Have heat losses assessed
Heat loss is the heat that the installation must replace under the calculation conditions. Ask which assumptions the professional uses and keep them with the result. A number without assumptions is difficult to check later.
If new windows or wall insulation are planned, provide the works programme. Sizing without considering the finished project can lead to an appliance unsuited to the use actually expected.
03
Read output under the correct conditions
For a hot-water radiator, output depends on operating temperatures. Fondital tables give different values for different ΔT conditions. This symbol describes a temperature difference; it is not the room thermostat setting.
Have the calculated requirement compared with output at the water temperatures planned by the installer. Comparing figures from different columns can suggest a performance difference that mainly comes from different measurement conditions.
04
Check that the solution fits
The validated output must then be matched to a feasible position. Windows, furniture, circulation and prescribed clearances limit usable space. Request a drawing showing the appliance and its connections, not just its stated width.
Bring the heat requirement, water temperatures and plan to EDIFIS. References can then be compared on a common basis. If the position changes, have the selection confirmed before finalising the order.
Before you decide
- Record volume and exposed walls.
- Describe insulation and planned work.
- Confirm calculation conditions.
- Compare output at the same temperatures.
The essentials
Your questions, our guidance.
Do rooms with the same floor area need the same output?
No. Their insulation, openings, height and exposure may differ.
Can I use the highest catalogue output directly?
No. Use the output corresponding to the project’s operating conditions.
From idea to project
Discover at EDIFIS
Explore FonditalHeating solutionsTowel radiators and heating demandConfirm references, configurations, finishes and availability for your project.
Documentation & references
EDIFIS design advice. For specifications and installation, consult the documentation for the selected reference.
Acova · heating requirements and output ↗Fondital · Exclusivo technical table ↗
