SIARELCO, Siargao's electric cooperative, averages 2 to 4 power outages per week during normal conditions. During typhoon season, blackouts can last days or weeks. After Super Typhoon Odette in 2021, parts of the island had no grid power for over three months. If you're building a rental villa, a properly sized generator isn't optional.
How to Calculate Your Generator Size
Generator sizing is about matching your peak electrical load. You don't need to power everything at once, but you need enough capacity for all the equipment that runs simultaneously during normal use.
Typical Load Values
| Appliance | Running Watts | Starting Watts | Notes |
|---|---|---|---|
| Split-type aircon (1.0 HP) | 750W | 2,250W | 3x surge on startup |
| Split-type aircon (1.5 HP) | 1,100W | 3,300W | Most common bedroom size |
| Split-type aircon (2.0 HP) | 1,500W | 4,500W | Living room / large bedroom |
| Refrigerator (inverter type) | 150W | 450W | Inverter models draw less |
| Pool pump (1.0 HP) | 750W | 2,250W | Runs 6-8 hrs/day |
| Pool pump (1.5 HP) | 1,100W | 3,300W | Larger pools |
| Water pump (0.5 HP) | 375W | 1,125W | Deep well or pressure pump |
| Electric water heater (instant) | 3,500W | 3,500W | No surge, but huge draw |
| LED lighting (whole villa) | 200-500W | Same | Depends on villa size |
| WiFi router + modem | 30W | Same | Always on |
| Washing machine | 500W | 1,500W | 3x surge |
| Microwave | 1,200W | 1,200W | No surge |
| Electric kettle | 1,500W | 1,500W | No surge |
The critical number is starting watts (surge). Air conditioners draw three times their running wattage for the first 2 to 3 seconds when the compressor kicks in. Your generator needs to handle this surge without tripping.
Generator Sizing by Villa Type
Here's a practical sizing guide based on common Siargao villa configurations:
| Villa Type | Key Loads | Running Load | Peak/Surge | Recommended Generator |
|---|---|---|---|---|
| 1BR cottage (no pool) | 1 aircon, fridge, lights, pump | 1.5 kW | 3.5 kW | 3.5-5 kVA |
| 2BR villa (no pool) | 2 aircons, fridge, lights, pump | 2.8 kW | 6.5 kW | 6.5-8 kVA |
| 2BR villa with pool | 2 aircons, fridge, pool pump, lights | 3.5 kW | 8.0 kW | 8-10 kVA |
| 3BR villa with pool | 3 aircons, fridge, pool pump, lights, heater | 5.5 kW | 12 kW | 12-15 kVA |
| 4BR resort villa | 4+ aircons, pool, full kitchen, laundry | 8.0 kW | 18 kW | 20-25 kVA |
Sizing rule of thumb: Take your total running load and multiply by 2 to 2.5x to account for surge. Then round up to the next available generator size. Oversizing by 20% is fine. Undersizing causes the generator to overload and shut down, which is exactly what happens at 2 AM when your Airbnb guest turns on the third aircon.
Diesel vs Gasoline vs Dual-Fuel
On Siargao, diesel is the clear winner for generators above 5 kVA. Here's why:
| Factor | Diesel | Gasoline | Dual-Fuel (Gas/LPG) |
|---|---|---|---|
| Fuel availability | Excellent (multiple stations) | Good | LPG harder to source on Siargao |
| Fuel cost per kWh | ₱15-20 | ₱22-28 | ₱18-24 |
| Engine lifespan | 15,000-30,000 hours | 3,000-5,000 hours | 5,000-8,000 hours |
| Maintenance cost | Higher upfront, lower per hour | Lower upfront, higher per hour | Moderate |
| Noise level | Louder (needs enclosure) | Moderate | Moderate |
| Available sizes | 3 kVA to 500+ kVA | 1 kVA to 15 kVA | 3 kVA to 25 kVA |
| Fire risk | Lower (diesel is less volatile) | Higher | Moderate |
Diesel generators cost more upfront (roughly 30 to 50% more than gasoline for the same kVA) but last 3 to 6 times longer and burn 20 to 30% less fuel per kWh. For a rental villa that might run the generator 4 to 8 hours daily during outages, diesel pays for itself within 12 to 18 months.
For a small 1BR cottage that only needs backup a few hours per week, a gasoline generator (₱25,000 to ₱45,000 for 3-5 kVA) is perfectly fine.
Automatic Transfer Switch (ATS): Non-Negotiable for Rentals
An ATS automatically switches between grid power and generator power when SIARELCO goes out. Without an ATS, someone has to manually start the generator and flip the transfer switch. At 2 AM during a thunderstorm. While your Airbnb guests are in the dark.
| ATS Type | Cost (installed) | Switching Time | Best For |
|---|---|---|---|
| Manual transfer switch | ₱5,000-8,000 | Manual (minutes) | Owner-occupied only |
| Basic ATS | ₱15,000-20,000 | 10-15 seconds | Budget rentals |
| Quality ATS with delay timer | ₱20,000-30,000 | 5-10 seconds | All rental villas |
| ATS + auto-start generator | ₱25,000-35,000 | 8-15 seconds | Best for Airbnb |
The ATS with auto-start is the standard for Airbnb villas on Siargao. It detects the outage, waits 5 seconds (to avoid starting for brief flickers), starts the generator automatically, and switches the load over. When grid power returns, it switches back and shuts down the generator after a cooldown period.
Generator Costs on Siargao
Prices on Siargao run 10 to 20% higher than Manila or Cebu because of shipping. Here are current market ranges:
| Generator Size | Diesel (New) | Gasoline (New) | Used/Imported |
|---|---|---|---|
| 3-5 kVA | ₱60,000-90,000 | ₱25,000-45,000 | ₱15,000-35,000 |
| 6-8 kVA | ₱100,000-150,000 | ₱45,000-70,000 | ₱40,000-80,000 |
| 10-12 kVA | ₱150,000-220,000 | Not common | ₱70,000-120,000 |
| 15-20 kVA | ₱220,000-350,000 | N/A | ₱100,000-180,000 |
| 25+ kVA | ₱350,000-500,000 | N/A | ₱150,000-300,000 |
Add installation costs:
| Installation Item | Cost |
|---|---|
| ATS (quality, installed) | ₱20,000-30,000 |
| Generator pad (concrete) | ₱5,000-8,000 |
| Sound enclosure | ₱15,000-25,000 |
| Fuel line + tank setup | ₱5,000-10,000 |
| Electrical connection to panel | ₱8,000-15,000 |
| Total installation | ₱53,000-88,000 |
Daniel Kipper, who built his 84 sqm cottage in Malinao, saved significantly by importing a used generator from his Tamba-Tikki project on Tambaliza island. If you have access to a reliable used unit, this is a legitimate way to cut costs. Just make sure to budget for a full service (oil change, filters, belt inspection) before putting it into regular use.
Monthly Running Costs
How much diesel a generator burns depends on the load. Running at 50 to 75% capacity is optimal for diesel engines.
| Generator Size | Fuel at 50% Load | Fuel at 75% Load | Monthly Cost (4 hrs/day avg) |
|---|---|---|---|
| 5 kVA | 0.8 L/hr | 1.2 L/hr | ₱2,400-3,600 |
| 8 kVA | 1.3 L/hr | 1.8 L/hr | ₱3,900-5,400 |
| 10 kVA | 1.6 L/hr | 2.2 L/hr | ₱4,800-6,600 |
| 15 kVA | 2.2 L/hr | 3.0 L/hr | ₱6,600-9,000 |
| 20 kVA | 3.0 L/hr | 4.0 L/hr | ₱9,000-12,000 |
Based on diesel price of ₱75/liter (Siargao, March 2026)
During normal conditions with 2 to 4 outages per week averaging 2 to 3 hours each, expect 8 to 12 hours of generator runtime per week. During typhoon season, this can jump to 4 to 8 hours per day for weeks at a time.
Generator + Solar: The Best Combo for Siargao
A generator alone handles outages. But combined with a solar and battery system, you get a setup that covers every scenario:
| Scenario | Solar + Battery | Generator | Combined |
|---|---|---|---|
| Short outage (1-3 hrs) | Handles it silently | Overkill for short outages | Battery handles it, no fuel used |
| Long outage (4-12 hrs) | Battery depletes | Handles it, burns fuel | Battery first, generator kicks in when battery low |
| Multi-day blackout (typhoon) | Panels recharge during day | Burns through fuel fast | Solar recharges battery by day, generator only at night |
| Normal days (grid available) | Offsets your electric bill | Sits idle | Solar saves ₱3,000-8,000/month on SIARELCO bills |
The hybrid approach is the gold standard for Siargao rental villas. A 6kW solar system (₱550,000) with a 5-8 kVA diesel generator (₱100,000-150,000) covers a 2BR villa for every scenario. The solar system pays for itself through SIARELCO savings in 5 to 7 years while the generator provides emergency backup.
For a full breakdown of solar system sizing and costs, see our solar power costs guide and off-grid infrastructure overview.
Maintenance Schedule
Tropical humidity, salt air, and extended idle periods are hard on generators. Follow this schedule:
| Interval | Task | Cost |
|---|---|---|
| Weekly | Run for 15-30 min under load (load banking) | Fuel only |
| Monthly | Check oil level, battery, coolant | Free |
| Every 250 hours | Oil + filter change | ₱1,500-3,000 |
| Every 500 hours | Air filter, fuel filter, belt inspection | ₱2,500-5,000 |
| Annually | Full service (all filters, coolant flush, valve check) | ₱5,000-10,000 |
Load banking is the most important maintenance item that people skip. Diesel generators that idle or run at very low load build up carbon deposits ("wet stacking") that damage the engine over time. Once a week, run your generator at 50% or higher load for 20 to 30 minutes. Turn on the aircons, pool pump, and water heater to create the load.
Frequently Asked Questions
What size generator do I need for an Airbnb villa on Siargao?
For a standard 2BR villa with pool, an 8 to 10 kVA diesel generator handles all typical loads including 2 aircons and the pool pump running simultaneously. If you have a water heater or more than 2 aircons, step up to 12-15 kVA. See the sizing table above for your specific configuration.
How often does SIARELCO lose power on Siargao?
Expect 2 to 4 outages per week under normal conditions, typically lasting 1 to 4 hours each. During typhoon season (June to November), outages are longer and more frequent. After major typhoons, blackouts can last weeks to months. SIARELCO has been investing in grid improvements, but reliability is still well below Manila or Cebu standards.
Should I buy a new or used generator for Siargao?
New gives you warranty and known condition. Used saves 40 to 60% but requires inspection. If buying used, check the hour meter (under 3,000 hours for diesel is good), look for oil leaks, and do a load test before purchasing. Shipping a used generator from another island (like Daniel did from Tambaliza) is viable if you have a trusted source.
Can I skip the generator if I have solar panels?
Only if you have a large battery bank (two 17.5 kWh batteries or equivalent) and are okay with limited power during extended cloudy periods. For an Airbnb property, we recommend a generator backup even with solar. Guests expect 24/7 power, and multi-day rain during typhoon season can drain batteries faster than panels can recharge them.
How loud is a generator? Will it bother guests or neighbors?
A typical 8-10 kVA diesel generator produces 72 to 80 dB at 1 meter, roughly as loud as a vacuum cleaner. A concrete block enclosure with acoustic foam lining reduces this by 15 to 20 dB. Place the generator at least 5 meters from bedroom windows and face the exhaust away from the house. Your neighbors are used to generator noise on Siargao.
Use our cost calculator to estimate your complete infrastructure costs including generator, solar, and water systems. For the full picture, check our complete cost guide.
