Solar Aircon Costs and Payback, the Honest Way: Estimate Savings from kWh

The honest way to estimate solar aircon payback is to work in kWh first and pesos second: find how many kWh your aircon uses, how many of those the solar will really replace (and how many it will export instead), multiply by your own rate and export credit, then divide your actual quote by those yearly savings. For example, a TCL TAC-11CSD/P7 1HP split (650 W, CSPF 7.11) uses about 1,053 kWh a year on its DOE label basis, worth about ₱12,636 a year at an example rate of ₱12 per kWh. That is the most solar can ever save on that aircon, before losses and exports.

We don’t publish prices for panels, inverters, batteries or installation, because they change daily. Instead, this guide shows the method so you can test any quote yourself in our solar savings calculator and solar payback calculator.

The two formulas that matter

Yearly savings (₱) = kWh used directly × your rate
                   + kWh exported × your export credit
                   − any new costs (for example battery losses)

Payback (years)    = what you actually pay ÷ yearly savings

Everything else is detail: working out the kWh honestly and using the right rates. A payback figure from a seller that doesn’t show the kWh behind it can’t be checked, so ask for the kWh.

Step 1: Put a kWh figure on the aircon

The aircon’s yearly kWh is the ceiling on what solar can save on it. The DOE label gives a standard way to estimate it. On older labels, monthly kWh is calculated as power input (kW) × 9 hours × 30 days × 0.5 for inverter units or 0.8 for fixed-speed units. Newer labels print lower figures on a different basis, so we apply the older formula ourselves to keep the comparison fair.

Rated input is from the DOE label or (Fujidenzo) the manufacturer’s page. The Fujidenzo CSPF is listed by a retailer. The label formula assumes 9 hours a day; if your household runs the aircon 12 hours a day in the hot months, scale up, and if it’s 6 hours, scale down. The aircon electricity cost calculator does this for any wattage and hours.

Step 2: Make the aircon efficient before you buy solar

The cheapest kWh is the one you don’t use. Look at two 1HP window units of similar size in the table:

• Fujidenzo WAR-100IGT: 800 W, fixed-speed despite the “Inverter Grade” name. Fujidenzo doesn’t claim an inverter compressor, and the retailer’s CSPF of 3.34 matches a fixed-speed unit. A retailer lists its capacity at 9,072 kJ/h.
• TCL TAC-09CWI/UB2: 850 W, inverter, CSPF 5.12 and 5 stars on its DOE label, 9,360 kJ/h.

The inverter unit is rated at more watts, yet on the label formula it uses 58 kWh a month less (172.8 − 114.75), because an inverter compressor slows down once the room is cool. That’s about 697 kWh a year, worth about ₱8,359 a year at our example ₱12 rate.

You can cross-check this with CSPF alone. Electricity for the same cooling is proportional to 1 ÷ CSPF, so the UB2 needs about 1 − (3.34 ÷ 5.12) ≈ 35% less electricity for the same cooling. Applied to the Fujidenzo’s 172.8 kWh, that gives about 113 kWh, close to the UB2’s 114.75 on the label formula.

What this does to a solar plan: 58 kWh a month is about 0.6 kW of panels on our example output (Step 3). So upgrading the aircon can shrink the solar system you need.

Aircon upgrade payback (years) = price difference between the two aircons
                                 ÷ yearly savings (₱8,359 in this example)

Our inverter vs non-inverter aircon guide explains the difference, and solar aircon myths covers “inverter grade” and similar labels.

Step 3: Work out how much the solar really replaces

This is where honest and optimistic estimates part ways. Solar only saves money on the kWh it actually displaces.

Setup A: Grid-tied solar with net metering

Here the question is timing. Solar used while it’s produced saves your full rate; solar exported earns the lower credit. With 1 kW of panels and the TCL P7 1HP:

Same panels, almost double the value, just from when the aircon runs. Our guide to offsetting your aircon bill with grid-tied solar and net metering walks through this example in detail, and net metering in the Philippines explains how credits work.

Setup B: A power station with portable panels

A power station saves money only on the kWh it delivers to your appliances. That’s limited by both the panels and the battery.

Example: EcoFlow DELTA 3 Plus with 2 × EcoFlow 400W portable panels (one panel on each of its two 500 W solar ports, a verified configuration):

Harvest upper bound: 800 W × 4 h × 0.8 ≈ 2.56 kWh a day ≈ 934 kWh a year
Value if every kWh replaced grid power at ₱12: ≈ ₱11,213 a year

That’s the ceiling. The DELTA 3 Plus holds 1,024 Wh, so once it’s full, extra sunshine is wasted unless you’re using power at that moment. If you only cycle the battery once a day for evening cooling, it delivers roughly 0.9 kWh (assuming 90% after losses), about 336 kWh a year, worth about ₱4,036 at ₱12. The real figure for most households sits between those two.

Example: EcoFlow DELTA Pro 3 with 1,760 W of EcoFlow panels (6 × 220W in series on High-PV plus 1 × 400W portable on Low-PV, both verified):

Harvest upper bound: 1,760 W × 4 h × 0.8 ≈ 5.6 kWh a day ≈ 2,056 kWh a year
Value at ₱12 if all used: ≈ ₱24,668 a year

With a 4,096 Wh battery, a DELTA Pro 3 can store most of a day’s harvest for evening and night cooling, so more of that ceiling is reachable. For the High-PV port, EcoFlow’s manual specifies its “Solar to XT60 Charging cable”; it doesn’t say whether the 220W panel’s included XT60i cable fits.

Power stations earn their keep mostly as brownout backup: the value of keeping the aircon, refrigerator and Wi-Fi running during an outage doesn’t show up in a kWh payback, but it’s real. See backup power for brownouts.

Setup C: Off-grid, replacing a generator

At a farm or beach house without a grid connection, solar replaces generator fuel, not grid kWh. The method is the same; only the rate changes:

Your generator cost per kWh = fuel cost per hour ÷ average kW the generator supplies
Yearly savings = solar kWh used × your generator cost per kWh

Use your own fuel receipts and run-hours. Our guide to off-grid aircon for a farm, beach house or remote home covers the sizing, and solar generator vs gas generator compares the two.

Step 4: Count the battery’s cost per kWh

A battery doesn’t make electricity; it moves it from day to night. Each kWh it stores carries a share of the battery’s price. A simple, honest way to see this:

Lifetime throughput (upper bound) ≈ capacity × rated cycles
Storage cost per kWh ≈ battery price ÷ lifetime throughput

To use the last column, multiply by the station’s price in tens of thousands of pesos. For example, a station priced at ten times ₱10,000 would have a storage cost about ten times the figure shown.

These are upper bounds. They assume a full cycle every day and ignore that capacity falls towards 80% over that life. Cycling a 4,000-cycle battery fully every day would take about 11 years to reach its rating, and EcoFlow quotes an estimated lifespan of about 10 years for several DELTA 3 models. If you only use the battery during brownouts, you’ll never use most of those cycles, so the battery is best judged as backup insurance, not a bill saver.

The practical takeaway: for bill savings, solar used directly in the daytime pays back fastest. Storing solar for night-time cooling adds a storage cost to every kWh, so check it against your grid rate.

Step 5: Test how sensitive your payback is

Rates move every month, and your aircon hours change with the weather. Test a range before you commit. For the TCL P7 1HP’s 1,053 kWh a year, if solar replaced all of it:

Then:

Payback (years) = your quote ÷ yearly value

Run the same test with a lower share of self-use (say 50% instead of 80%) and with your export credit for the rest. If the payback only works with every assumption at its most optimistic, it probably won’t work.

What stretches payback, and what shortens it

Stretches it:

• Running the aircon mostly at night on a grid-tied system without a battery (exports earn less)
• Oversizing the system well beyond daytime use
• Rainy-season and cloudy-day output; panels also produce less than their rated watts in heat (see why a solar panel gives less than its rated watts)
• Storing solar in a battery only to save on bills
• A fixed-speed aircon that needs more kWh for the same comfort

Shortens it:

• Using solar while it’s produced: daytime cooling, pre-cooling in the late afternoon
• An efficient inverter aircon with a high CSPF
• Sizing to your real daytime load
• Good aircon habits: the DOE recommends 24°C, clean filters and a clean outdoor coil

For the bigger question of whether solar suits your home at all, see is solar worth it in the Philippines.

What to buy: checklist

1. The aircon (biggest, cheapest lever):

• TCL TAC-11CSD/P7 1HP split (650 W, CSPF 7.11, 5 stars): Shopee (TCL Official Store) · Lazada (TCL). The same listings offer the 1.5HP TAC-14CSD/P7.
• Kolin KA-100GQAIINV32 1HP window (740 W, CSPF 5.60): Lazada (Kolin)
• TCL TAC-09CWI/UB2 1HP window (850 W, CSPF 5.12): Shopee (TCL Official Store) · Lazada (TCL)
• TCL TAC-09CSD/FBI 1HP split (660 W, CSPF 6.28 per TCL’s spec sheet): Shopee (TCL Official Store) · Lazada (TCL)

2. The solar, depending on your goal:

• Lower bills on the grid: a grid-tied system from a licensed installer, with net metering. Compare quotes on our compare solar quotes page and see the installers directory.
• Brownout backup plus some solar: EcoFlow DELTA 3 Plus (Lazada) with 2 × EcoFlow 400W portable panels. Buyer guide: DELTA 3 Plus
• Overnight cooling from stored solar: EcoFlow DELTA Pro 3 (Shopee) with 6 × EcoFlow 220W and 1 × EcoFlow 400W portable. Buyer guide: DELTA Pro 3

3. Your numbers: your rate from electricity rates, your aircon’s label watts, your hours, and your quotes in the solar savings and solar payback calculators.

Portable panels and power stations are plug-and-play and you can set them up yourself following the manual. Rooftop panels, hybrid inverters and anything connected to your home’s wiring need a licensed electrician or PEE, an LGU electrical permit and, for grid export, your electric company’s net-metering process.

Bottom line

An honest solar aircon estimate starts with the aircon’s kWh, not the system’s watts. Make the aircon efficient first, count only the kWh the solar will really replace, value exports at your export credit rather than your full rate, add a storage cost for any battery, and use your own rate and quotes in the calculators. Done this way, you’ll know whether a TCL TAC-11CSD/P7 on grid-tied solar, an EcoFlow DELTA Pro 3 for overnight cooling, or simply a more efficient aircon gives you the best return.