Net metering is a credit, not a paycheck

One of the most common things we hear during a survey is some version of: “So Meralco will pay me for my solar?” It is an understandable hope. It is also not quite how net metering works, and getting it wrong can lead you to buy the wrong size of system.

What net metering actually does

A grid-tie solar system powers your home first. When your panels produce more than you are using at that moment, the extra flows out to the grid. Under net metering, Meralco replaces your meter with a two-way (bidirectional) meter that records two things separately: the power you import from the grid, and the power you export to it.

At the end of the billing period, the exported power is turned into a peso credit and subtracted from your bill. That is the whole mechanism. You do not receive a cheque or a bank transfer. You receive a smaller bill.

Why the credit is worth less than what you pay

The rate you pay for each kilowatt-hour you buy from Meralco includes more than the cost of generating that power. It also covers transmission, distribution, taxes and other charges. The credit for power you export is based on the generation cost only, so it is lower than the full retail rate.

In plain terms: a kilowatt-hour you use yourself, straight from your panels, saves you the full retail rate. A kilowatt-hour you export earns a smaller credit. Both help, but they are not equal.

What happens to extra credit

If your credit in a month is larger than your bill, the leftover is generally carried forward to later bills rather than paid out. The detailed rules are set by the Energy Regulatory Commission and can change, so ask Meralco for the current terms when you apply. Either way, the point stands: net metering reduces bills. It is not an income stream.

What this means for sizing

Because self-used power is worth more than exported power, the best-value system for most homes is one sized to the power you use while the sun is up, not the biggest array your roof can hold. A few practical consequences:

Size to your daytime use. Your Meralco bill shows how much you use in a month. What you tell us about when you use it, day or night, matters just as much.
Shift what you can to daytime. Laundry, ironing, water pumps and pre-cooling a room in the afternoon all use solar directly instead of exporting it.
Be wary of “oversize it and earn”. Extra panels that mostly export earn the lower credit rate. They are not always worth the added cost.
Expect exports anyway. On weekends or days you are out, some power will flow to the grid. Net metering makes sure that power is not wasted.

Applying is a separate step

Net metering is not automatic. After installation, an application goes to Meralco with the required documents, followed by an inspection and the meter change. This can take weeks to months, depending on the paperwork and the queue. Until the two-way meter is installed, your system still powers your home during the day; you just do not get credit for exports yet.

Net metering covers renewable energy systems up to 100 kW, which includes practically every home and most small-business rooftops.

The short version

Net metering is a bill credit, not a cash payout.
Exported power is credited at a lower rate than the power you buy.
Solar you use yourself is worth the most, so size for daytime use.
The application, inspection and meter change take time. Plan for it.

If someone promises that net metering will “pay” for your system on its own, ask them to show the numbers on your own bill.

Solarman PH

When a battery is worth it

Batteries get a lot of attention in solar marketing. They are also the part that most changes the price of a system. In our own planning bands, a 5 kW hybrid system starts at ₱318,000, compared with ₱235,000 for a 5 kW grid-tie system. That difference should buy you something you actually need.

Here is how we think about whether a battery is worth it for a particular home or business.

What a battery does, and does not do

A plain grid-tie system shuts down when the grid goes down. This is a safety requirement called anti-islanding: it stops your panels from feeding power into lines that workers may be repairing. So during a brownout, a grid-tie system gives you nothing, even on a sunny day.

A hybrid system adds a battery and a hybrid inverter. When the grid fails, it can keep selected circuits running from the battery and the panels. When the grid is up, it can store daytime solar and release it in the evening instead of exporting it at the lower net-metering credit rate.

What a typical home battery does not do is run the whole house, including every air conditioner, through the night. Batteries are sized for the loads that matter most, and the backup circuit is wired for exactly those loads.

When a battery is usually worth it

Outages cost you something real. Spoiled stock in a shop chiller, lost work hours, a medical device, a water pump, or simply a household that cannot cope with frequent brownouts.
Much of your use is in the evening. If the house is empty during the day and busy at night, storing solar for later lets you use more of it yourself.
You would rather store than export. Because exported power earns less than you pay for imported power, storing it for the evening can make sense, as long as the battery cost is justified.

When it usually is not

Outages are rare or short where you are, and your main goal is a lower bill.
You use most of your power in the daytime. Working from home with aircon running in the afternoon is a good match for grid-tie solar alone.
Your budget only fits a battery by shrinking the panel array. A smaller array with a battery can save less than a properly sized grid-tie system.

If you do want one, size it honestly

Two numbers matter. The first is the battery’s usable capacity in kilowatt-hours: how much energy it can actually deliver. The second is the inverter’s power rating in kilowatts: how much load it can run at once. A large battery behind a small inverter still cannot start several heavy appliances together.

Start by listing the loads you need during an outage: lights, fans, refrigerator, router, maybe one aircon, maybe a pump. That list, not a brochure, decides the battery size.

Questions to ask before you buy

What is the battery brand and model, and its usable capacity in kWh?
What is the warranty, in years and in cycles or energy throughput?
Which circuits are on backup, and which are not?
What happens at the moment the grid fails: is there a pause, and will my devices notice?
If I start with grid-tie, can this inverter take a battery later, or would I need to replace it?

That last question matters. If outages are a “maybe” for you, one option is to start with a correctly sized grid-tie system and add storage later, provided the equipment allows it. Ask for that in writing.

The short version

Buy a battery to solve a real problem: outages that hurt, or evening use that grid-tie cannot cover. If neither applies, a well-sized grid-tie system is usually the better value. Either way, the decision should start from your bill and how you live, not from a package.

Solarman PH

What a quote must name

Two quotes for “a 5 kW system” can describe very different equipment. Before you compare prices, check what each quote actually names. A quote you can hold an installer to should spell out these five things in writing.

The module brand. Which company made the solar panels, and the model, so you can look up its datasheet and manufacturer warranty yourself.
The inverter model. The exact brand and model number, not just “inverter included”. The inverter decides how your system behaves day to day, and during a brownout.
The array size in kW. The total panel capacity, and how it adds up: how many panels, at what wattage each.
The workmanship warranty. How long the installer stands behind the installation itself, and what that covers. This is separate from the manufacturers’ warranties on panels and inverter.
Every exclusion. What the price does not include. If something is not written in the quote, do not assume it is covered. Ask.

If a line only says “solar panels” or “complete system”, ask for the details in writing before you pay anything. A good installer will not mind.

A price with no brand is not a quote.

Solarman PH