Sizing an array for one appliance is the clearest way to understand solar, because it reduces the question to one load, one number of hours, and Philippine sunlight. Here is that calculation for a turbo broiler.
A turbo broiler drawing 1,400 W for 1 hours a day uses about 1.40 kWh. At 4.8 peak sun hours that needs roughly 1 panels of 550 W, an array of about 0.55 kW, costing ₱24,750 to ₱41,250 installed.
Calculate it for your own turbo broiler
Change any box. The result updates as you type.
Planning estimate. The rate box is prefilled with a regional average; the figure on your own bill is the one that matters. Power is draw while running, not while switched on.
The arithmetic, step by step
- Daily energy. 1,400 W for 1 hours is 1.40 kWh.
- Panel output. A 550 W panel at 4.8 peak sun hours makes 2.64 kWh on paper.
- Apply the derate. Tropical heat, dust, wiring and inverter conversion take about 20 percent, leaving 2.11 kWh per panel.
- Divide and round up. 1.40 divided by 2.11 gives 1 panels.
Peak sun hours is not daylight hours. It is how many hours of full-strength sun the day is equivalent to, which is why a twelve-hour Philippine day counts as roughly five. Heat matters more here than in temperate countries, because panels lose output as cell temperature rises and Philippine roofs get hot.
Panels needed by panel size
| Panel rating | Output per day | Panels | Array |
|---|---|---|---|
| 400 W | 1.54 kWh | 1 | 0.40 kW |
| 450 W | 1.73 kWh | 1 | 0.45 kW |
| 550 W | 2.11 kWh | 1 | 0.55 kW |
| 610 W | 2.34 kWh | 1 | 0.61 kW |
Bigger panels mean fewer of them, not less roof. Output per square metre has barely changed; the modules simply got physically larger. Most Philippine installers now fit 550 W or 610 W modules as standard.
How run time changes the array
| Hours/day | Energy | Panels | Grid cost/month |
|---|---|---|---|
| 2 h | 2.80 kWh | 2 | ₱1,242 |
| 4 h | 5.60 kWh | 3 | ₱2,484 |
| 6 h | 8.40 kWh | 4 | ₱3,725 |
| 8 h | 11.20 kWh | 6 | ₱4,967 |
| 10 h | 14.00 kWh | 7 | ₱6,209 |
| 12 h | 16.80 kWh | 8 | ₱7,451 |
Read the row matching how long you actually run it. Sizing to an optimistic figure is the most common way people end up with an array that never quite covers what they hoped it would.
Running it after dark
A turbo broiler is a heating element and a fan. It cooks faster than a conventional oven and uses less energy per meal for that reason, but the draw while running is high.If this load runs at night, panels alone will not carry it. Storing 1.40 kWh means a battery of roughly 1.94 kWh once you allow for inverter losses and an 80 percent depth of discharge. At Philippine prices that is a meaningful addition to a quote, and it buys reliability rather than savings.
The inverter is the other constraint. This load surges to roughly 4,200 W on start, so an inverter rated to run it may still refuse to start it. Size for the surge, not the running figure.
Roof, orientation and shading in the Philippines
The 1-panel figure assumes an unshaded roof with reasonable orientation. Philippine roofs rarely give you that for free. South-facing is the textbook answer for the northern hemisphere, but this close to the equator the sun passes almost overhead, so east and west orientations lose far less here than they would in Europe or the United States. A flat roof with panels tilted 10 to 15 degrees works well and sheds rain.
Shading is the real enemy and it is not proportional. One shaded panel in a string can drag down the entire string, so a single coconut palm or a neighbour water tank can cost you far more than its shadow suggests. Walk the roof at 9am and again at 3pm before agreeing a layout, not at noon when everything looks clear. Where shade is unavoidable, microinverters or optimisers isolate the affected panel instead of letting it penalise the rest.
Dust and salt matter too. Coastal installations accumulate salt film, and anywhere near a road collects dust through the dry season. Both cut output quietly, and a rinse two or three times a year recovers most of it.
Grid-tied, hybrid or off-grid for this load
Grid-tied is the cheapest and simplest. It offsets the turbo broiler while the sun is up and draws from the grid otherwise. It also shuts down completely during a brownout, because the inverter is required to disconnect for the safety of line crews. Most Philippine households should start here.
Hybrid adds a battery and keeps selected circuits alive during outages. It costs meaningfully more and lengthens payback, since the battery buys reliability rather than savings. In areas with frequent brownouts that trade is usually worth making.
Off-grid means no utility connection at all, which requires sizing for the worst week of the year rather than the average, plus enough storage to ride out several cloudy days. For a single load like this it is rarely the right answer unless there is genuinely no grid to connect to.
| Appliance | Watts | kWh/day | Panels |
|---|---|---|---|
| Refrigerator | 150 W | 1.20 | 1 |
| Small Refrigerator | 120 W | 0.96 | 1 |
| Chest Freezer | 200 W | 1.40 | 1 |
| Rice Cooker | 700 W | 0.70 | 1 |
| Induction Cooker | 1,800 W | 1.80 | 1 |
Adding loads is not simply additive in practice, because appliances rarely run at the same moment. Sizing each one in isolation and totalling the panels produces an array considerably larger than a household actually needs. Use the whole-system pages once you have a sense of the individual figures.
What it costs on the grid instead
Running the same turbo broiler from the grid costs ₱620.90 a month and about ₱7,554 a year at the current Meralco rate of ₱14.7833. Against an installed array cost of ₱24,750 to ₱41,250, simple payback on this load alone is roughly 3.3 to 5.5 years.
In practice nobody installs solar for a single appliance. Size the whole system once using the system price pages and treat this figure as the share of an array this load justifies. Full running-cost detail sits on the turbo broiler cost page.