How many kWh does 1 kWp produce in Romania: monthly table by region

1. The short answer, in numbers

One installed kilowatt (1 kWp) of solar panels produces between 1,150 and 1,400 kWh per year in Romania, depending on the region. The figure assumes the reference conditions: fixed system, facing south, tilted at 30-35°, no shading — the standard scenario in PVGIS, the European Commission's solar radiation database.

This value — annual kWh per installed kWp — is called specific yield. Once you know it for your area, you can estimate any system's production with a single multiplication (#3).

The regional benchmarks:

• Dobrogea and the coast: ~1,380 kWh/kWp/year — the sunniest part of the country;
• South (the Romanian Plain, including Bucharest): ~1,280 kWh/kWp/year;
• West (Banat and Crișana): ~1,240 kWh/kWp/year;
• Centre (the Transylvanian Plateau): ~1,190 kWh/kWp/year;
• North and mountain areas: ~1,150 kWh/kWp/year.

Worth noting: the gap between the extremes is only 20%. On a typical 5-8 year payback, the region adds or removes roughly one year.

2. The monthly table: kWh per month for 1 kWp

The values below are kWh produced by 1 kWp in a month, derived from PVGIS for representative locations in each region, rounded to whole kWh:

Month	Dobrogea/coast	South	West	Centre	North/mountain
January	55	48	44	41	38
February	72	65	61	58	55
March	108	100	96	92	88
April	140	130	126	122	118
May	160	150	148	142	138
June	168	158	154	149	146
July	175	164	160	155	152
August	165	154	150	144	140
September	133	122	120	115	110
October	98	90	88	84	80
November	64	58	55	52	51
December	42	41	38	36	34
Annual total	1,380	1,280	1,240	1,190	1,150

The regions follow solar radiation, not administrative borders: "Dobrogea" means Constanța and Tulcea; "south" is the Romanian Plain from Oltenia to Bărăgan; "west" is Banat and Crișana; "centre" is the Transylvanian Plateau; "north and mountain" covers Suceava, Maramureș, Harghita and the intra-mountain basins. On a regional border, the truth sits between two columns.

3. The scaling rule: multiply by your system's kWp

Production scales linearly with installed power. Take your region's value from the table and multiply by the system's kWp:

• 3 kWp in the west: 3 × 1,240 ≈ 3,700 kWh/year;
• 5 kWp in the south: 5 × 1,280 = 6,400 kWh/year;
• 8 kWp in the centre: 8 × 1,190 ≈ 9,500 kWh/year;
• 10 kWp in Dobrogea: 10 × 1,380 = 13,800 kWh/year.

The rule works per month too: 4 kWp in the centre produce 4 × 36 ≈ 144 kWh in December and 4 × 155 = 620 kWh in July.

Two caveats. First: kWp means the DC power of the panels, not the inverter rating — 12 × 440 W panels are 5.28 kWp even on a 5 kW inverter; a DC/AC ratio up to 1.2 clips peaks only a few hours per year. Second: double the production is not double the savings — injected surplus is worth less than a self-consumed kWh, and oversizing tops the list of prosumer mistakes. Size for consumption, not for roof area.

4. The summer/winter ratio: why December is 4-5× weaker than July

Look down any column: July produces 4-5 times what December does, in every region. Three physical effects multiply together:

1. Shorter days: under 9 hours of daylight at the winter solstice in Bucharest, over 15 and a half at the summer one.
2. A low sun: ~22° above the horizon at noon on 21 December versus almost 70° on 21 June — the same light spreads over a larger area, so each square metre of panel receives less.
3. Cloud cover: December and January have the most overcast and foggy days of the year.

The result, valid across all regions: about 70% of annual production comes in the April-September half; December and January together contribute only 6-7%.

The practical consequence: with a heat pump or an EV, you produce the least exactly when you consume the most — don't size on the annual average without checking December; see integrating solar + heat pump + EV. The good news: net-metering rolls the summer surplus over into the weak months, as explained in what is a prosumer.

5. "Efficiency": what it actually means — and what you're probably looking for

"Panel efficiency" gets used for three different things:

1. Panel conversion efficiency — 21-23% for current monocrystalline panels. It only tells you how much surface 1 kWp occupies (about 4.5-5 m²). A more efficient panel does not produce more kWh per kWp — it's just smaller at the same power. It matters on tight roofs, not on your bill.
2. System performance ratio — 80-86% on a properly built installation: real output over theoretical output, after thermal, cabling, inverter and soiling losses. PVGIS assumes 14% system losses, already baked into the table in #2.
3. Specific yield (kWh/kWp/year) — the number in the table, and usually what people actually want: kWh, not percentages.

A useful check: divide your last 12 months of production by the installed kWp and compare with your region's column. Below 90% of the table value, look for a cause — new shading, dirty panels, a dead string.

6. What the table assumes — and what lowers your numbers

The table in #2 is a realistic starting point, not a guarantee. The assumed conditions and the usual corrections:

• Orientation: south is the reference. South-east or south-west lose 3-5%, an east-west roof typically loses 10-15%, north 30-40% — full azimuth tables in panel orientation and tilt.
• Tilt: anywhere between 20° and 45° costs only a few percent. Vertical mounting (façade, railing) loses far more — real numbers in balcony solar yield over 12 months.
• Shading: the most brutal factor. A shaded panel drags down the whole string it belongs to; a badly placed chimney costs more than the entire gap between two regions.
• Temperature: ~0.4% lost per °C above 25°C cell temperature — a clear, cool May day can match a scorching July one.
• Dust and snow: 3-5% in rain-free months; snow stops production entirely a few days a year in the mountains.

Combined, two houses in the same village can normally differ by 10%. To verify your exact address, PVGIS is free and takes five minutes — the steps are in the orientation article.

7. The worked example: 5 kWp in Brașov, month by month

Want the rule applied to a concrete case, with money and bills? We published separately the production of a 5 kWp system in Brașov: its full monthly table, scaling to 3/7/10 kWp, comparison with neighbouring counties, and the factors that cut into theoretical output.

Brașov is a good example precisely because it is not representative of its region: the mountain microclimate pulls it down to ~1,150 kWh/kWp/year, below the "centre" column's average. It's the perfect demonstration that the regional table gives you the order of magnitude, while a local check (PVGIS or an installer measuring on site) gives you the final figure.

8. From kWh to money: the calculators and your county's page

Production only becomes interesting once multiplied by your tariff and self-consumption rate. In order:

1. The capacity calculator — starts from your monthly consumption and county, and proposes the right system size.
2. The payback calculator — enter your tariff and estimated self-consumption to see the break-even year; the theory is in solar system payback.

For local context — active companies, indicative county prices — there are dedicated county pages under /panouri-fotovoltaice-{county} (in Romanian), for example the Constanța county page, the sunniest region in the table.

9. What this means for your system

The numbers worth remembering:

• 1 kWp produces 1,150-1,400 kWh/year in Romania; the region matters, but the maximum gap is 20%.
• System production = your region's value × the system's kWp. That's it.
• About 70% of production comes in April-September; December is 4-5× below July — plan for winter, not for the average.
• Panel efficiency (21-23%) doesn't tell you how many kWh you get — specific yield (kWh/kWp/year) does.

Practical steps: size for consumption with the calculator, check payback at your tariff, then request quotes from verified companies and compare the promised production against the table in #2. An offer promising 1,500 kWh/kWp/year in central Transylvania isn't optimistic — it's wrong, and better discovered before the deposit than after the first year of bills.