How do I work out the right generator size for my project?
Add up everything you plan to plug in, allow for the fact that not everything runs at full power at the same time, and add a small buffer for safety. The calculator above does all of that for you — pick your project type, list your loads (or pick them from our library), and you get a recommendation sized for our UAE rental fleet in under a minute.
What is the difference between kW and kVA?
kW is the actual work your equipment does. kVA is the size of generator you need to deliver that work — it has to be a bit bigger because motors, drives, and electronics also draw power that doesn't turn into useful work. As a rule of thumb, kVA = kW ÷ 0.8 for a typical mix of equipment. Generators are sold and rented in kVA because that's what their alternator can deliver.
What does the headroom setting do?
It's a cushion above your real load. Pick None (0%) to size to exact demand, Lean (10%) if your equipment list is complete, Standard (20%) for most jobs, or Heavy (30%) when the load list may still grow or change. Too little headroom and the generator can trip; too much and you're paying for capacity you never use.
What is the usage factor and why does it matter?
It's the share of your equipment that actually runs at the same time. A catering kitchen peaks at meal prep, lighting peaks after sunset, office gear is idle during the show — they don't all hit maximum together. Pick Wide (0.70) when loads rarely peak together, Standard (0.80) for typical mixed use, Mixed (0.85) when most loads run together, Tight (0.95) for almost-always-on sites, or Full (1.00) when everything runs at once. Choosing a project type sets a sensible default for you.
How does the Dual power option work?
In the Setup section, switch Dual power to On when you want to split your loads across two gensets — for example a Primary machine for the show floor and a Secondary machine for catering, or a Primary + Backup pair for redundancy. A Label set picker appears (Primary + Backup is the default, plus Primary + Secondary, Primary + Nighttime, or your own custom pair). Each load row then shows a Pri / Sec toggle so you tag which genset it belongs to, and the calculator returns a sizing for each machine so you can plan and quote both at once.
Should I use Simple list or By zone / area?
Simple list is the fastest path — one flat list of equipment for a single project area. Pick By zone / area when you want to organise loads by location (Stage, VIP, Catering, IT) so each area is grouped separately, with its own diversity factor. Once you're in By zone mode you can also switch the Sizing approach in Setup from Site-wide to Per-zone, which sizes a separate genset for each zone — useful when the areas need to run independently.
How do the Zone "Diversity" and Sub-zone "Usage" factors work together?
They stack. Sub-zone Usage models the fraction of that area's equipment running together, and Zone Diversity then applies on top across the whole zone. The combined effect lowers the peak demand used for sizing, reflecting that not everything hits maximum at once. For example, a sub-zone at 80% Usage inside a zone at 75% Diversity contributes 0.8 × 0.75 = 60% of its nameplate to peak sizing, before headroom and site adjustments.
How do I deal with UAE summer heat?
Generators lose a small amount of capacity in the heat — the calculator applies roughly a 2% derate at 41–45°C, 5% at 46–50°C, and more above that. It already defaults to Normal — an outdoor UAE site at 41–45°C, sea level. If your project is in hotter conditions or poor ventilation, indoors, on the coast, or up at altitude (Hatta, Jebel Hafeet), pick the matching Site conditions tile (Normal, Very hot, High altitude, Indoor, Coastal) and the calculator adjusts automatically.
Why does the calculator recommend a bigger generator than the total load I entered?
The recommendation already includes your headroom, the usage factor, the heat / altitude adjustment for your site, and any motor start-up surge from tagged motor loads. We aim for the generator to run within a healthy 30–85% loading range, ideally around 50–75% — running a diesel genset too lightly for long stretches causes wet-stacking, and running it too heavily leaves no headroom for surges. So the suggested unit is sized for the full project, not just the steady-state minimum.
What loads cause start-up surges?
Big motors that switch on at full voltage — chillers, refrigeration compressors, large pumps, hoists, tower cranes. They can briefly draw six times their normal current. If you tag a load as a motor with direct-on-line starting, the calculator factors that surge into the size so the lights don't dim when the compressor kicks in. Soft-starters and VFD-driven motors don't have this problem.
What do "Independent" and "Linked" mean for motor loads, and how do start method and order affect sizing?
Tag any motor-driven load as a motor so PowerMatch sizes for its inrush. Independent means each motor has its own starter, so only one starts at a time and the genset is sized for a single start. Linked means the motors share one starter and fire together, so the genset is sized for all of them starting at once. The start method sets the inrush: Direct On Line draws about 6 times full-load current, Star-Delta and Soft Starter about 2.5 times, and a VFD about 1 time, which is easiest on the genset. Order only matters when "Stagger motor starts" is enabled in Engineering overrides; otherwise the largest motor is treated as the governing start.
When does the calculator suggest two or more generators in parallel?
When your load is bigger than the largest single unit in our fleet, or when you want a safety net (drop one machine and the others keep going). The calculator will suggest 2–5 matching units of the same model. For very large loads it routes you to our engineering team for a custom design.
What does the recommendation screen show?
A headline required genset power figure plus a recommended unit from our fleet. For most jobs that's a single Prime generator running the whole load; for larger loads it becomes a Synchronised set of matched units running in parallel. You also get a running-load summary, any warnings or notes, and an optional Add backup generator toggle for full N+1 standby with automatic transfer. From there you can email yourself the PDF report, request a quote, or share it with a colleague.
What size generator do I need for a wedding or event tent in Dubai?
Air conditioning decides it. Tent AC dwarfs the lighting, sound, and catering loads, so the answer follows your tonnage. Pick the Tents project type, add your AC from the load library along with lighting and catering, and the calculator sizes it for UAE summer conditions. Most mid-size wedding and event tents land in the 100–500 kVA range once the air conditioning is counted — but run your own numbers above rather than guessing from a range.
How many kVA do I need for an exhibition stand?
A typical stand — lighting, screens, a fridge, a coffee machine — often fits in 10–30 kVA, and the venue or organiser usually specifies the supply they'll provide. If you're powering the stand independently or running heavier kit, pick the Events project type, add your equipment from the library, and the calculator gives you the exact figure with the right headroom.
How much does a 100 kVA generator rental cost in the UAE?
Rates depend on rental duration, season, and what the package includes — cabling, distribution boards, automatic transfer switches, standby support. Rather than quote a misleading flat number: size your project with the calculator above, then use Request a quote on the result screen and you'll get current pricing for the exact unit and accessories your project needs.
Can I size a three-phase generator with this calculator?
Yes. Every load row has a phase selector (3φ / 1φ), and the engine models how single-phase loads land across the R/Y/B legs of a three-phase genset — sizing against the worst-loaded leg, the way an engineer would. Voltage standards cover the UAE/GCC norms: 380/220 V, 400/230 V (default), and 415/240 V at 50 Hz.
Is this calculator a substitute for an electrical engineer?
No. It gives you a solid first estimate for budgeting and planning. Critical infrastructure, parallel installations, very motor-heavy industrial loads, and any project where downtime is costly should be reviewed by our engineering team. They can validate the recommendation against your specific site before equipment is dispatched.