Most boilers specified for villas in Jordan are sized from a catalogue, not from a calculation. A figure gets picked that feels safe, a margin gets added “to be sure,” and the result is a unit that is comfortably oversized, and just as comfortably expensive to run for the next twenty years.
Why oversizing is the default, and what it costs
An oversized boiler short-cycles: it fires, satisfies the thermostat quickly, shuts off, and repeats. Every cycle has losses. Over a heating season those losses add up, efficiency drops well below the figure on the data sheet, and the components wear faster. The owner pays for it in fuel and in early replacement, long after the specifier has left the project.
What a real sizing calculation needs
Sizing a boiler properly is a heat-loss problem, not a floor-area rule of thumb. At minimum we work from:
- The building envelope: wall and roof construction, glazing and insulation, with realistic U-values rather than design-table ideals.
- The design outdoor temperature for the specific location. A villa in Amman and one in the Jordan Valley are not the same problem.
- The emitter system: underfloor heating runs at low flow temperatures and changes the calculation entirely versus radiators.
- Domestic hot water demand: number of bathrooms, simultaneous draw, and whether storage or instantaneous.
The shortcut that actually works
If you do not have time for a full calculation early in the project, send us the drawings. We will run the heat loss, recommend an output band rather than a single number, and flag where the emitter choice will move it. That review is free, and it is far cheaper than a boiler that was never the right size to begin with.