Solar Computation: Size Your Solar Setup From Your Electric Bill

Last checked 20 October 2026 · JH Solar guide

How This Solar Computation Works

A solar computation answers three questions. How much energy do you use in a day? How much panel power makes that energy under Philippine sun? And how much battery and inverter does your goal need? People look for a solar panel calculator because quotes are hard to compare when you do not know the size you need, and brownouts make backup urgent.

Five steps, then the analysis

Start with the kWh on your bill; the price per kWh on your bill is optional and gives your rate. List your appliances: common ones fill in instantly from our list, and for anything else the AI helper looks up typical watts, which you can change. Pick a goal, set the battery hours, and check the highest load running at once.

Analyze my setup sends only appliance names and numbers. Back come option cards: a JH Solar package first, then budget-friendly, moderate and premium setups with separate parts, and portable power stations. Each card lists parts, an estimated price range, a short reason, how much of your use it covers, and a detailed wiring diagram with the real breaker and cable sizes. Prices are ranges; JH Solar confirms the setup and price after a site visit.

How to Read Your Meralco or Electric Cooperative Bill

Every solar computation starts with the bill. Meralco and electric cooperative bills look different but carry the same items, and you need only three: kWh used, billing period and total amount. Look near the meter readings: present minus previous reading is the kWh you used (some meters use a multiplier, so take the kWh figure the bill prints). The billing period shows the start and end dates.

The rate is split into many lines, so divide the total amount by the kWh used to get your effective rate. Charges change every month, so last month’s rate is only a guide. For a wider view, see the Department of Energy’s electricity rate data for the Philippines. In the calculator, type the amount from your own latest bill; without it, the tool uses a fixed ₱13 per kWh and says so.

From Bill to kWh: The First Step in Solar Computation

Panels are sized in energy, not pesos, so the first step of any solar computation is to get kWh. If your bill shows kWh, use it. If you only have pesos: monthly kWh = bill ÷ rate per kWh. Divide by 30 for daily kWh, as the calculator does.

Hot months bring more aircon hours, so average two or three bills for the panels, and keep your highest month in mind for the battery and inverter.

Your Appliance List: How to Compute Solar Setup Load by Load

This is how to compute solar setup sizes load by load: daily kWh = watts × hours per day ÷ 1,000, added up for every appliance. Take the watts from each label when you can. Example from our records: an inverter-type aircon averaging 800 W × 8 h ÷ 1,000 = 6.4 kWh a day.

In the calculator, type an appliance and pick it from the list of common Philippine appliances. If yours is not there, the AI helper looks up a typical value. Some appliances run on and off: a refrigerator compressor runs about 40% of the time, so the tool counts only that share. For each one, tick Use at night on battery and type the hours after 6 PM.

The list gives two figures. Daily kWh sizes the panels and battery. The highest load at once sizes the inverter. The tool first shows what happens if everything runs together, here 800 + 150 + 120 + 50 + 100 = 1,220 W. Lower it to what usually runs at the same time. On a JH Solar unit your whole house panel runs through it, so in a brownout this figure must stay within 7 kW (Version 1) or 11 kW (Version 2).

Sun Hours and Losses

Two fixed values turn daily kWh into panel size in a solar computation. Both appear under Fixed assumptions in the calculator.

Peak sun hours count hours of full-strength sunlight. In the Philippines they are typically about 3.5 to 5 a day, depending on place and season; the calculator uses 4, a careful average. Check your city on the Global Solar Atlas map of solar resource.

Panels never deliver their full rating to your sockets. The tool assumes 75% of panel power reaches your loads after heat, dust, cable and inverter losses. A shaded or rarely cleaned roof will do worse, which the site visit checks.

Sizing Panels, Inverter and Battery

With daily kWh, sun hours and losses in hand, the rest of the solar computation is three short formulas. The calculator uses 620 W panels, so the count you see is for that size.

• Panels: panel power in kW = daily kWh ÷ (sun hours × 75%). Divide by one panel’s kW and round up. For hybrid and off-grid, the tool adds the small charging loss for the energy that passes through the battery.
• Inverter (kW, not kWh): the highest load running at once, plus 25% extra room for start-up from aircon compressors, refrigerators and pumps, rounded up to the next half kW. Also check the surge rating in the inverter’s data sheet.
• Battery size: you cannot use a battery’s full label size (you stop before it is empty to protect its life), and some energy is lost on the way to the outlet. Battery size = night kWh ÷ (90% × 95%). Only the night counts: by day the panels run your loads and refill the battery.

Three Goals, Three Different Results

Grid-tie needs no battery, but a grid-tied inverter shuts down during a brownout to protect line workers, so it gives no backup. Unused daytime energy earns credit only under net metering: read the Meralco net metering FAQ and check current requirements with your utility.

Hybrid adds a battery for the appliances you mark for the night. Solar output is near zero by 6 PM in the Philippines, so the battery window starts at 6 PM and ends at the hour you pick, up to 6 AM. Off-grid uses the same battery math with no power company at all, so the tool adds 25% more panels for cloudy days.

How Net Metering Changes Your Solar Computation

With grid-tie, ask what happens to solar you do not use the moment it is made. Without net metering it is held back by the inverter (zero export) or wasted. With net metering, the surplus goes to Meralco or your cooperative and earns a peso credit, which since the 2025 rule changes can roll over to later bills.

Credits are worth less than the power you buy: the DOE says exports are credited at the utility’s blended generation cost, not the full rate per kWh. So keep your solar computation sized to your own daytime use, and treat exports as a bonus. Systems up to 100 kW qualify, and the account must be in your name. For documents, fees and timelines, see our net metering guide for the Philippines.

Worked Examples

These follow the calculator’s solar computation steps with its fixed assumptions. Examples only, not quotes.

Example 1, a 576 kWh bill, grid-tie. The bill shows 576 kWh and ₱9,500, so the rate is ₱9,500 ÷ 576 ≈ ₱16.49 per kWh (an example, not a current rate). Daily use: 576 ÷ 30 = 19.2 kWh. Panels: 19.2 ÷ (4 × 0.75) = 6.4 kW, or 11 panels of 620 W (6.82 kW total). That is more than Version 1’s 6-panel array and within Version 2’s largest array of 16 panels.

Example 2, the appliance list, hybrid. To run the aircon on battery for 8 hours after 6 PM: 6.4 ÷ (0.9 × 0.95) ≈ 7.49 kWh of battery. The whole list running together is 1,220 W, so the inverter is about 2 kW. Version 1 is rated at 7 kW with a 16.38 kWh battery, so both fit on paper; we confirm the fit after a site visit.

Example 3, Version 2’s battery. The rated 15.36 kWh × 0.9 × 0.95 ≈ 13.13 kWh to your appliances, about 13 hours at a steady 1 kW. Real loads rise and fall, so actual hours will differ.

What a Solar Computation Cannot Tell You

A solar computation has clear benefits: it shows your real usage, lets you compare quotes on the same panel size, and helps you spot a package that is too small. The estimate still cannot check:

• Your actual parts. Each panel string must fit the voltage and current limits of each solar input on the inverter you buy (see how a solar charge tracker works), and the price ranges change with stock and brand.
• Shade from a tree, water tank or neighbor’s wall, which can cut output far more than its size suggests.
• Your roof: direction, tilt, space, and whether the trusses can carry panels and stay put in a typhoon.
• Wiring and permits for your LGU and utility.

Sending Your Bill Safely

For a solar computation we only need the kWh used, the amount, the billing period and your city or municipality.

• Before you take the photo, hide your name, address and Customer Account Number (CAN), for example with a sticky note.
• Tap Send my estimate to JH Solar under your options, or paste your Copy my estimate summary, so we see the same numbers you saw.

Next Steps: Quote, Inquiry, Email Updates or DIY

Once your solar computation is done, you have four paths.

Ask for a quote or send an inquiry

Pick an option, send your estimate with your city and a few roof photos showing where panels could go, or use our contact page for quotes and inquiries. We reply with questions, then arrange a site visit. The price is confirmed after that visit, because roof, distance and wiring change the parts list.

Get solar updates by email

Email updates are being set up. When sign-up opens, a subscribe link will appear in the calculator.

Do it yourself

If you want to build or manage the project yourself, start with the best solar panel, inverter and battery brands, then compare solar providers in the Philippines or the budget-friendly options. To understand the wiring before you buy anything, open the solar setup diagram hub, then the step-by-step guide with pictures for your system:

• Off-grid setup guideA small battery system you can wire on the DC side.
• Hybrid system guidePanels, battery and grid power together.
• Grid-tied guideDaytime savings and net metering steps.

Portables, and when to step up

A portable power station with a solar panel suits phones, a fan, a laptop and lights, and the calculator shows one or two when they fit part of your list. If your computation shows several kWh a day or an aircon, a portable will run out fast. Our step-up is JH Solar Version 1 and Version 2: floor-standing all-in-one units with the inverter and battery in one cabinet.

Using the Solar Panel Calculator on Your Phone

The calculator is built for phones. A few tips make it easier:

• Open a photo of your bill or your utility’s app in another tab, then switch back to copy the kWh.
• Tap the popular appliance buttons to add common loads with one tap.
• Open Connection list under a wiring diagram to read every connection in words.
• Use Copy my estimate, then paste it into your message app.
• The page does not keep your inputs after you close it, so copy or send your estimate first.

Philippine Context: Brownouts, Typhoons, Heat and Rain

A solar computation for a Philippine home must fit local conditions. Brownouts are why many families add a battery, so note how long yours last and which loads truly matter at night. Heat lowers panel output, and the rainy season brings fewer peak sun hours, so expect less output from June to October than the yearly average.

Typhoons bring strong winds. PAGASA issues tropical cyclone wind signals; mounting must suit your area’s wind loads, and the array should be inspected after storms. Net-metering and zero-export rules change, so check with your utility (as of October 2026).

Conclusion

A good solar computation turns your bill and appliance list into a few clear numbers: daily kWh, battery size, highest load, inverter size and panel count. The assumptions stay fixed for Philippine sun and heat, so pick the goal that matches your real need: grid-tie, hybrid or off-grid.

Use the options to compare packages and quotes on equal terms. Then let a site visit settle what the numbers cannot: shade, roof, parts and permits. When you are ready, send your estimate to JH Solar for a quote, or follow the DIY path above.