1Project & Building
Pick a building type to seed defaults. You can edit everything afterwards.
2HVAC — Air Conditioning
Split AC, VRF outdoor units, chillers, AHUs, FCU motors. Use the building heat-load calculator if you don't yet know the cooling capacity. Heat-load calculator →
3Pumps & Motors
Water transfer, booster, fire (jockey + main), sewage, HVAC chilled-water and condenser pumps, cooling-tower fans. Starting type matters: Direct-on-Line motors draw 6× their rated current at start.
4Lifts & Vertical Transport
Passenger lifts, service lifts, escalators, dumb-waiters. Modern VVVF lifts are gentler on starting current than older AC two-speed.
5Lighting & General Power Outlets
Add total lighting and socket-outlet load. As a guide: offices ~12 W/m² lighting, hotels ~15 W/m², factories ~10 W/m². Sockets typically diversify to 30-50%.
6Kitchen Equipment
Hotels, hospitals, restaurants. Combi ovens, walk-in coolers, induction hobs, dishwashers, exhaust fans. Diversity is high in commercial kitchens — typically 40-60% running simultaneously at peak.
7Laundry Equipment
Industrial washers, dryers, irons, calenders, finishers. Hotels and hospitals only. Dryers are heavy continuous loads; washers have brief inrush.
8Medical Equipment
Hospital backup loads — OT lights, ICU, ventilators, MRI, CT, X-ray, dialysis, autoclaves, lab refrigeration. Critical loads must always be 100% backed up.
9Industrial / Process Machinery
Factory motors, compressors, conveyors, mixers, presses, CNC machines. Use VFD wherever possible — cuts starting current to ~1.2×.
10IT & UPS Systems
UPS systems, server rooms, data halls. UPS adds an inrush surge on start (~4× rated kVA briefly). For data centres, consider 2N redundancy.
11EV Chargers
Increasingly common for hotels and offices. AC chargers (7-22 kW) are continuous loads; DC fast chargers (50-150 kW) need careful generator sizing.
12Other Loads
Anything else — pool pumps, garden lighting, fountains, signage, water features, future expansion allowance.
Why starting current matters
A motor at start draws 4–7× its rated current. The genset must handle this surge without voltage drop greater than 15%, or the motor stalls.
Why tropical derating
Sri Lankan ambient is 35°C; gensets are rated at 25°C ISO. Derate ~5% for cooling efficiency loss in tropical conditions.
Why diversity factor
Not every load runs simultaneously. Hotels run ~70% of HVAC at peak; factories run ~80% of motors. Apply realistic diversity per category.
Beyond this calculator
Final sizing should account for harmonics, future expansion, parallel operation needs, and the actual single-line diagram. Talk to our power engineers.