Running Two Aircons on Solar: Load Planning and Why Staggered Starts Matter

To run two aircons on solar, add up their maximum input watts (not their rated watts) plus every other load that may run at the same time, and make sure the total stays under your inverter’s continuous rating. Then start the aircons one at a time, so their high-draw periods don’t overlap. Two TCL TAC-09CSD/FBI 1HP inverter splits (660 W rated, up to 1,100 W each) need up to 2,200 W together, which rules out an 1,800 W station and points to something like the EcoFlow DELTA Pro 3 (4,000 W continuous, 4,096 Wh) or a PowMr 6.5kW hybrid inverter.

The battery and panels roughly double too. This guide shows how to plan the load, why staggering starts matters, and the battery and solar maths for two units.

Why two aircons is more than “double one”

With one aircon, there’s a single peak to plan for. With two, you have to plan for the moment both peak together, and that moment is easy to cause by accident:

• You switch both on when you get home on a hot afternoon.
• Both have timers set to the same time.
• Power comes back after a brownout and both restart together, if your units have an auto-restart feature.

An inverter (the box that turns battery power into 230 V AC) has a continuous rating it can hold indefinitely and a surge rating it can hold only briefly. If the load stays above the continuous rating, the inverter protects itself, usually by shutting off its output. Everything plugged in goes dark, including your refrigerator and Wi-Fi. Good load planning keeps you from ever reaching that point.

Step 1: Use maximum input, not rated input

An aircon’s rated input is the power it draws under the standard test conditions on its energy label. An inverter aircon can draw more than that while it pulls a hot room down to temperature, and much less once it settles. For energy and battery maths, use the rated figure. For inverter sizing, use the maximum.

These verified models publish a range:

Rated inputs are from each model’s DOE label, except the TCL TAC-09CSD/FBI (TCL’s spec sheet). For the 1.5HP FBI, TCL’s spec sheet gives a rated input of 1,050 W, while its DOE label says 1,130 W; we use the label figure.

Two things stand out. First, the gap between rated and maximum can be large: the TCL UB2 1HP is 850 W rated but up to 1,450 W. Second, a lower rated figure doesn’t always mean a lower maximum: the Kolin KA-100 is rated higher than the TCL FBI 1HP (740 W vs 660 W) but has a lower published maximum (888 W vs 1,100 W).

If your aircon’s maximum input isn’t published, ask the manufacturer before you buy the inverter. The TCL TAC-11CSD/P7 1HP split, for example, has a very low rated input (650 W, CSPF 7.11) but no maximum we could verify.

Step 2: Add up the worst case

Write down what could be running at the same moment, using maximum figures for the aircons and label watts for everything else.

Then add the rest of the house: a refrigerator, fans, lights, a rice cooker, a water pump. Use the watts on each appliance’s label. A rice cooker or electric kettle running at the same time as two aircons is a common way to trip an inverter.

Leave headroom. Aim to keep the worst-case total comfortably below the inverter’s continuous rating, not right at it. Inverters run hotter and less efficiently near their limit, and Philippine afternoons are hot.

Step 3: Pick an inverter with room to spare

Here’s how verified power stations and hybrid inverters compare against two 1HP TCL FBI units (2,200 W combined maximum):

EcoFlow figures are from EcoFlow Philippines’ store pages; PowMr figures are from PowMr’s catalogue.

Check each outlet, too

With a power station, each aircon plugs into its own AC outlet, and each outlet has its own current limit. EcoFlow lists “13A(x4) Max per port” for the DELTA 3 Max Plus. TCL’s spec sheet gives the FBI 1.5HP a maximum current of 8.5 A and the FBI 1HP 5.8 A, so either fits one outlet. Check your own aircons’ maximum current against the station’s per-outlet limit in its manual, and never run two aircons from one outlet with a power strip.

With a hybrid inverter wired into the house, each aircon should be on its own dedicated circuit with a correctly rated breaker. That’s work for a licensed electrician, under a PEE-signed plan and an LGU electrical permit.

Step 4: Stagger the starts

Staggering is free and it’s the single most effective thing you can do with two aircons on one inverter.

Why it works. An inverter aircon’s draw changes over time. Right after you switch it on in a hot room, it runs fast to pull the temperature down, drawing towards the top of its range. Once the room approaches the setpoint, it slows and the draw falls towards the bottom of its range. If you start the second unit only after the first has settled, their peaks happen at different times, and the combined draw stays well below the sum of their maximums.

How to do it:

1. Start the first aircon and leave the second off.
2. Watch the output reading on the power station’s screen or app, or your hybrid inverter’s display. You’ll see the draw climb, then fall as the room cools.
3. Start the second aircon once the first has settled to a steady, lower reading.
4. Offset your timers. If you use timers, set them well apart rather than for the same minute.
5. After a brownout, if your aircons restart on their own when power returns, switch one off and bring it back after the other has settled.
6. Pre-cool while the sun is up. If you’re on solar, start the cooling while the panels are producing, so the high-draw phase is covered by solar rather than the battery.

Why non-inverter units are harder. A fixed-speed aircon has no gentle phase: its compressor switches fully on and off with the thermostat, many times a night. You can’t control when those restarts happen, so two units will sometimes start at the same moment. The DOE labels and spec sheets we checked don’t publish starting current for any model, so you can’t size the inverter’s surge with confidence. That’s one more reason to use inverter aircons on solar; our inverter vs non-inverter guide explains the difference.

Step 5: Size the battery for two

Battery maths roughly doubles. Using two TCL TAC-09CSD/FBI 1HP units for 8 hours a night:

Realistic example: 660 W × 8 h = 5,280 Wh, + 10% ≈ 5,800 Wh (5.8 kWh)
Worst case:      1,320 W × 8 h = 10,560 Wh, + 10% ≈ 11,600 Wh (11.6 kWh)

How long verified stations last on the realistic example (capacity × 0.9 ÷ 660 W):

The DELTA 3 Max Plus is a capable inverter for two aircons, but EcoFlow Philippines says its expansion adapter isn’t available here, so its battery stays at 2,048 Wh. For two aircons through a whole night, you need a station that expands, such as the DELTA Pro 3 or DELTA Pro. See planning EcoFlow extra batteries with solar and try your own figures in the EcoFlow runtime calculator.

With a PowMr hybrid, the battery bank is separate. Its capacity in Wh is the nominal voltage × amp-hours on its label. Choose it with your installer so its charge and discharge currents match the inverter. At 6,500 W, PowMr’s 48 V model draws roughly 6,500 ÷ 48 ≈ 135 A from the battery before losses, so cables and fuses must be sized by a professional.

Step 6: Can solar refill it?

Refilling 5.8 kWh every day, before any daytime use, takes a sizeable array:

• DELTA Pro 3: the verified EcoFlow-panel setup of 6 × EcoFlow 220W in series on High-PV (1,320 W) plus 1 × EcoFlow 400W portable on Low-PV gives 1,760 W, about 5.6 kWh a day on our example. That nearly covers two aircons overnight on a sunny day and nothing else. For more, swap the Low-PV panel for 6 × EcoFlow 125W bifacial panels in parallel (750 W, daisy-chained through their own leads): 2,070 W in total, about 6.6 kWh a day on our example. Our check flags that their bifacial (back-side) current of 20.4 A can exceed the port’s 20 A limit in bright, reflective conditions, while the standard 19.2 A is within it. EcoFlow’s manual specifies its “Solar to XT60 Charging cable” for the High-PV port; EcoFlow doesn’t say whether the 220W panel’s included XT60i cable fits, so buy the XT60 version. Details are in our DELTA Pro 3 solar guide.
• DELTA Pro: 6 × EcoFlow 220W in series (1,320 W) is verified, about 4.2 kWh a day on our example. Not enough for two aircons every night without another charging source.
• PowMr hybrid: with up to 6,000 W (4.5kW) or 6,500 W (6.5kW) of PV input, there’s room for a much larger array, designed by your installer within the 55–450 V MPPT window. See our PowMr hybrid inverter guide.

The honest conclusion: running two aircons all night, every night, from solar alone is a big system. Most homes get further with a mixed plan.

Practical plans that work

• Day on solar, night on grid. Run both aircons in the afternoon while the panels are producing, then let the grid handle the night. The battery covers brownouts.
• One at night, two in the day. Cool the main bedroom overnight from the battery and use the second aircon only in sunny hours.
• Smaller second unit. A 0.75HP Kolin KAG-75WCINV (725 W rated, up to 900 W) for a small room instead of a second 1HP.
• Cool fewer rooms. Put children in one cooled room, close doors, and use fans elsewhere.
• Raise the setpoint. The DOE recommends setting the aircon at 24°C, cleaning filters and keeping the outdoor coil clean.

What to buy: checklist

Two efficient inverter aircons with published maximums:

• TCL TAC-09CSD/FBI 1HP split (660 W, up to 1,100 W): Shopee (TCL Official Store) · Lazada (TCL). The same listings offer the 1.5HP TAC-12CSD/FBI.
• Kolin KA-100GQAIINV32 1HP window (740 W, up to 888 W): Lazada (Kolin)
• Kolin KA-150GQAIINV32 1.5HP window (1,010 W, up to 1,212 W): Lazada (Kolin)
• Kolin KAG-75WCINV 0.75HP window (725 W, up to 900 W): Lazada (Kolin)

An inverter with headroom and an expandable battery:

• EcoFlow DELTA Pro 3 (4,000 W, 4,096 Wh): Lazada (EcoFlow PH) · Shopee (Altitude PH). Buyer guide: DELTA Pro 3
• EcoFlow DELTA Pro 3 Smart Extra Battery: Lazada
• Or EcoFlow DELTA Pro (3,600 W, 3,600 Wh): Shopee (EcoFlow Philippines), with a DELTA Pro Extra Battery. Buyer guide: DELTA Pro
• Or EcoFlow DELTA 3 Max Plus (3,000 W, 2,048 Wh) for daytime and short evening use: Shopee (EcoFlow Philippines) · Lazada (EcoFlow PH)
• Or a PowMr 6.5kW 48V hybrid inverter for a wired, larger system: Lazada (PowMr)

Panels:

• 6 × EcoFlow 220W portable (High-PV on DELTA Pro 3, or DELTA Pro): Lazada (EcoFlow PH)
• 1 × EcoFlow 400W portable (Low-PV on DELTA Pro 3): Lazada (EcoFlow PH)
• Or 6 × EcoFlow 125W bifacial in parallel on Low-PV for 750 W: Lazada (EcoFlow PH) · Shopee (EcoFlow)

Bottom line

Two aircons on solar work when you plan for the moment they peak together. Size the inverter on their combined maximum input plus everything else that may run, choose a station or hybrid inverter with clear headroom, and start the aircons one at a time so their pull-down peaks don’t overlap. Then be realistic about energy: two 1HP inverter units overnight need about 5.8 kWh on our example, which calls for an expandable station like the EcoFlow DELTA Pro 3 with an extra battery and about 1.8 kW of panels, or a hybrid system designed by a licensed installer.