Inverters by power
Inverters by power is the filter that sorts the range by rated AC output, the figure the grid operator approves and the number your array size has to be matched against. Residential units run from 3 kW and 5 kW through 6 kW, 8 kW and 10 kW to 15 kW and 20 kW, with commercial machines beyond 50 kW. Balcony and module-level units start at 800 W. Narrow further by brand or phases. Guide
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250 W - 300 W
- 375 W
- 400 W
- 500 W
- 600 W
- 700 W
- 800 W
- 1000 W
- 1200 W
- 1500 W
- 1600 W
- 2000 W
- 2200 W
- 2500 W
- 2700 W
- 3000 W
- 3300 W
- 3500 W
- 3600 W
- 3680 W
- 3700 W
- 4000 W
- 4200 W
- 4500 W
- 4600 W
- 5000 W
- 5200 W
- 6000 W
- 6200 W
- 6500 W
- 7000 W
- 7500 W
- 8000 W
- 8200 W
- 8500 W
- 9000 W
- 10000 W
- 11000 W
- 12000 W
- 12500 W
- 14000 W
- 15000 W
- 16000 W
- 17000 W
- 17500 W
- 18000 W
- 19900 W
- 20000 W
- 21000 W
- 22000 W
- 23000 W
- 25000 W
- 27000 W
- 29900 W
- 29990 W
- 30000 W
- 33000 W
- 33300 W
- 35000 W
- 36000 W
- 40000 W
- 45000 W
- 50000 W
- 60000 W
- 66600 W
- 70000 W
- 75000 W
- 80000 W
- 90000 W
- 100000 W
- 105000 W
- 110000 W
- 115000 W
- 120000 W
- 125000 W
- 130000 W
- 135000 W
- 136000 W
- 150000 W
- 175000 W
- 200000 W
- 215000 W
- 225000 W
- 250000 W
- 255000 W
- 300000 W
- 350000 W
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List of products
Related power categories
- Inverters 3600 W
- Inverters 5000 W
- Inverters 10000 W
- Inverters 20000 W
- Inverters 50000 W
- Inverters by number of phases
Rated AC power: the number that sizes the system
An inverter is specified by its rated AC output in watts, and that is the value this filter uses. It is not the same as the array size in kWp, nor the same as the maximum DC input power the unit will accept, nor the maximum apparent power in kVA it can deliver. Sizing means holding three numbers together: how many kWp of modules you are installing, how much AC power the inverter is allowed to push into the grid, and how much DC power its inputs can absorb before it starts limiting.
The catalogue runs from 250 W module-level and balcony units up to 350 kW commercial machines, in the fine steps manufacturers actually build, for example 3680 W, 4600 W or 19900 W. Those odd values exist because national rules cap single-phase feed-in or connection size at a specific figure, so pick the exact band your connection approval allows rather than rounding up.
FROM THE FIELD
"People still size the inverter one to one with the array and then wonder why winter output looks flat. A DC to AC ratio around 1.1 to 1.25 earns more energy over a year than a perfectly matched pair, because the array only reaches its rated output for a handful of hours in clear cold conditions. The small amount you clip at midday in July is worth less than what you gain every morning and every overcast afternoon."
Ladislav Proc · Photovoltaics specialist, ONSA Plus
How to choose inverter power
Start from the constraint, not the catalogue. In most European connections the binding limit is what the distribution operator has approved for feed-in, and everything else is sized around it. Only when the connection is generous does the array itself set the inverter size.
Then work in this order: approved AC output, then array kWp and the DC to AC ratio, then the DC input window and MPPT arrangement, and finally headroom for a battery or a later extension. Use this filter to land on the exact band, then check the datasheet limits before you order.
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Sizing the inverter against array kWp
The array is rated in kWp under standard test conditions: 1000 W/m² and 25 °C cell temperature. Real arrays reach that only briefly, because cells run hotter than 25 °C whenever the sun is strong, and losses in cabling, soiling and orientation take another slice. A 10 kWp roof in central Europe rarely delivers more than about 8.5 kW to the inverter input, which is why a smaller inverter is not automatically undersized.
- South-facing, unshaded, optimal tilt: the array peaks high, so keep the ratio nearer 1.1.
- East and west split roofs: the two halves peak at different times of day, so a ratio of 1.3 or more is normal and clipping stays negligible.
- Flat roof with low tilt: a broad, lower peak also tolerates a higher ratio.
- Shaded or partially obstructed roofs: size on realistic yield, not on nameplate kWp, and consider module-level optimisers before oversizing.
DC to AC oversizing and clipping
The DC to AC ratio is array kWp divided by inverter rated AC kW. A ratio above 1.0 means the array can occasionally produce more than the inverter can pass through. The inverter then moves the operating point away from the maximum power point and holds output at its rating, which is clipping. Clipping is not damage, it is a design choice. At ratios up to about 1.25 the annual energy lost to clipping is typically a fraction of a percent, while the gain in morning, evening and overcast production is much larger. Above roughly 1.3 on a well-oriented south roof the losses start to become visible.
Tip from practice
Check the inverter's maximum DC input power and maximum input current per MPPT before you commit to an oversized array. The permitted DC to AC ratio is a datasheet value, not a rule of thumb, and exceeding the current limit on one tracker can void the warranty even when the total DC power looks acceptable.
Rated AC output, apparent power and maximum DC input
Three power figures appear on every datasheet and they are not interchangeable.
- Rated AC output (W or kW): the continuous active power the unit delivers to the grid. This is the number in the category name, the number on the connection application and the number the grid operator approves.
- Maximum apparent power (VA or kVA): the total the unit can deliver including reactive power. Grid codes often require operation at a power factor down to 0.8, so a 10 kW inverter may be rated 10 kVA or 11 kVA. Some operators assess the connection on kVA rather than kW.
- Maximum DC input power (Wp): the largest array the manufacturer allows on the inputs. It is usually 1.2 to 1.5 times the AC rating and it caps how far you can oversize.
- Maximum input current and voltage: per MPPT limits that decide string layout independently of any power figure.
Typical residential bands
Most family houses land in one of three bands, and the band usually follows the phase arrangement of the connection as much as the roof area.
- 3 to 6 kW: small roofs and single-phase connections, typically 4 to 7 kWp of modules. Values such as 3680 W and 4600 W exist because they sit exactly under common single-phase feed-in caps.
- 6 to 10 kW: the mainstream family-house size, typically 7 to 12 kWp, almost always three-phase, and the usual starting point for a hybrid system with storage.
- 10 to 20 kW: large houses, heat pump plus EV charging, or a small farm building, typically 12 to 25 kWp. The 19900 W band exists to stay under a 20 kW approval threshold.
- Under 1 kW: balcony systems and module-level conversion, where the 800 W band matches the plug-in limit used in several countries.
Commercial bands and multiple inverters
Above 20 kW the logic changes. Commercial units from 25 kW to 350 kW are three-phase, use higher DC voltages and more strings per tracker, and are usually chosen so that the plant divides cleanly into sections. Two 50 kW units on a 100 kW roof keep half the plant producing during a fault or a service visit, and let you split roof orientations across separate machines. On large sites the decision is between fewer central units, which are cheaper per kW, and more string units, which are easier to lift, replace and stock as spares.
Headroom for batteries, heat pumps and later expansion
An inverter sized exactly to today's array leaves no room for the changes that usually follow. If a battery is planned, remember that a hybrid unit's battery charge and discharge power is a separate rating from its PV input, and that backup output is often lower still. If a heat pump or a wallbox is coming, more self-consumption capacity is worth more than a marginal reduction in clipping. Practical headroom means one spare MPPT input, DC input power above the current array, and a connection approval that already allows the larger figure.
Power bands at a glance
| Inverter band | Typical array | Typical application |
|---|---|---|
| 250 to 800 W | 1 to 2 modules | Balcony systems and module-level conversion |
| 3 to 6 kW | 4 to 7 kWp | Small roofs, single-phase connections, apartments |
| 6 to 10 kW | 7 to 12 kWp | Mainstream family house, three-phase, hybrid with storage |
| 10 to 20 kW | 12 to 25 kWp | Large house with heat pump and EV charging, small farm |
| 20 to 50 kW | 25 to 60 kWp | Workshops, hotels, small commercial roofs |
| 50 kW and above | 60 kWp upwards | Industrial roofs and ground mounts, often several units |
Swipe the table to the left
Frequently asked questions about inverter power
What size inverter do I need for a 10 kWp array?
Usually an 8 to 10 kW inverter. A DC to AC ratio of 1.1 to 1.25 is standard, so 10 kWp of modules pairs well with an 8 kW or 10 kW unit. Confirm the choice against your approved feed-in limit first.
Can the array be larger than the inverter?
Yes, and it usually should be. Oversizing the DC side by 10 to 25 % raises annual yield because arrays rarely reach their rated output. Stay within the inverter's maximum DC input power and the current limit per MPPT stated on the datasheet.
What is clipping and does it damage the inverter?
Clipping is the inverter holding output at its rating when the array could produce more, by shifting away from the maximum power point. It causes no damage and is a normal design outcome. At sensible ratios the annual energy lost is a fraction of a percent.
Which power figure does the grid operator care about?
The rated AC output, and in many countries the maximum apparent power in kVA. Connection applications are assessed on what the inverter can push into the network, not on the array size in kWp or the maximum DC input.
What is the difference between kW and kVA on an inverter?
kW is active power, the energy that does work. kVA is apparent power, which includes the reactive component grid codes require the inverter to supply. A 10 kW unit may be rated 10 or 11 kVA, and some operators assess the connection on the kVA figure.
Why do inverters come in odd sizes like 3680 W or 19900 W?
They are built to sit just under regulatory thresholds. 3680 W matches a 16 A single-phase limit, and 19900 W stays below a 20 kW approval boundary. Choosing the band that fits your approval avoids a slower or stricter connection process.
Should I oversize the inverter for a battery I might add later?
Not the AC rating, but plan the headroom. In a hybrid unit the battery charge and discharge power is a separate specification from the PV input, and the backup output is often lower again. Check those three ratings against your intended battery.
Is one large inverter better than two smaller ones?
One unit costs less per kW and is simpler to commission. Two units keep half the plant producing during a fault or service, allow separate roof orientations and are easier to handle. Above about 30 kW the split approach is common on commercial roofs.
What happens if the inverter is too small for my roof?
Nothing breaks, but you clip more energy on clear days and waste array capacity. The bigger risk is exceeding the maximum DC input power or the input current per MPPT, which the manufacturer treats as operation outside specification.
Does inverter power decide how many phases I need?
Largely, yes. Single-phase units are common up to about 6 kW because operators cap single-phase feed-in, and above that three-phase is the norm. Compare the options under inverters by number of phases once the power band is set.
Inverter sizing depends on the array, the consumption profile and the output your grid operator will approve at the connection point.
About ONSA Plus
Why installers across Europe source inverters from us
ONSA Plus is a European B2B distributor of photovoltaics, battery storage, heat pumps and EV charging stations. In our own EU warehouses we keep over 1,500 products from 25+ brands, including Huawei, Solis, SolaX and Dyness.
We are not just a trading company. We design and service energy systems ourselves, so we answer questions on inverter sizing, oversizing ratios and grid approval from engineering practice, not from a catalogue. You handle a warranty claim directly with us and you buy per job.
