--- title: "Which solar panel wattage is cheapest per watt? | ComparePV" description: "Does a watt cost less on a bigger solar module? Live shop offers split into five power classes, in Poland and across markets, with spreads and shop counts." source: "https://comparepv.com/articles/which-power-class-is-cheapest-per-watt" image: "https://comparepv.com/static/images/og/articles/which-power-class-is-cheapest-per-watt.jpg" updated: 2026-10-09 --- # Which power class is cheapest per watt Does a watt cost less on a bigger solar module? Live shop offers split into five power classes, in Poland and across markets, with spreads and shop counts. By [Bart Szablowski](https://comparepv.com/authors/bart-szablowski) · Updated 9 October 2026 · 9 min read ## The analysis On this page 1. Does a watt get cheaper on a bigger module? 2. How the offers are split into power classes 3. Price per watt by power class 4. What this means when you buy 5. Limits of this data Figures and denominatorsRelated readingReferences **In short:** In Poland a watt costs a median 0.157 EUR/W before tax in the 400 to 449 W class and 0.134 EUR/W at 600 W and up, where the middle half of offers runs from 0.128 to 0.144 EUR/W. Inside the same shop, 39 of 46 shops listing both 450 to 499 W and 600 W and up price the bigger class lower per watt. Hold each median against its class's spread before you pick a size: where the spreads overlap, the offer you pick matters more than the class. A shop's module prices rise with the watts. The question is how fast, measured as price per watt. If a 600 W module costs less than one and a half times a 400 W module, its watt is cheaper, and the offers shops list today show whether it does. ### Does a watt get cheaper on a bigger module? Only if the step between class medians is larger than the spread inside each class. Two checks decide it. Does the median price per watt before tax fall from one 50 W power class to the next? And is that fall larger than the spread of prices inside each class? If it isn't, two offers picked from neighbouring classes can go either way, and the class tells you little. The prices are for modules only. Mounting, inverter, cabling and labour aren't in them, and some of those costs follow the number of modules rather than the watts. ![Rows of dark solar modules on tilted mounts on a flat roof with mountains in the background](https://comparepv.com/static/images/articles/flat-roof-tilted-module-rows.webp) *Tilted rows of modules on a flat roof; clamps and labour are counted per module, so the watts on each module change the cost per watt installed. Image: [Oscar Cavazos](https://commons.wikimedia.org/wiki/File:Instalaci%C3%B3n_de_paneles_solares.jpg), [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0).* ### How the offers are split into power classes The pool is the one from [solar panel price per watt by market](https://comparepv.com/articles/solar-panel-price-per-watt-by-market): 2,685 single rooftop module offers from 117 shops, priced before tax and converted to euro. The watt is the rated power the shop printed, which is the module's power at standard test conditions: 1000 W/m², 25 °C cell temperature, AM1.5 spectrum. Each offer goes into one of five classes by that rating. Every class is 50 W wide, except the last, which takes everything from 600 W up. The exact filters are in Figures and denominators below the article. #### Two views: Poland, and every market but the United States Price levels differ between markets. Mix them freely and you mostly measure which markets sell which sizes, not what size does to price. The first view is Poland on its own. I picked it because every class there held offers from at least 20 shops when this article was written; the Shops column gives today's count. The second is every market in the pool except the United States. I left US shops out because their price level sits above the European one (the market article shows it) and because they hold a large share of the smallest class: 132 of its offers across all markets, against the total in Figures and denominators. Left in, they would make the 400 to 449 W class look dear for a reason unrelated to its size. That view isn't a European figure. The pool covers 18 markets, and every one outside Europe other than the United States stays in. ### Price per watt by power class Read each table two ways. Down the Median column, see how far the price moves from one class to the next. Along each row, see how wide the middle half is: the band from the 25th to the 75th percentile, where half of a class's offers sit. Poland: | Class | Median (EUR/W) | Middle half (EUR/W) | Offers | Shops | | --- | --- | --- | --- | --- | | 400 to 449 W | 0.157 | 0.138 to 0.186 | 242 | 26 | | 450 to 499 W | 0.149 | 0.137 to 0.164 | 387 | 33 | | 500 to 549 W | 0.146 | 0.137 to 0.161 | 339 | 33 | | 550 to 599 W | 0.136 | 0.126 to 0.151 | 68 | 22 | | 600 W and up | 0.134 | 0.128 to 0.144 | 135 | 22 | Every market but the United States: | Class | Median (EUR/W) | Middle half (EUR/W) | Offers | Shops | | --- | --- | --- | --- | --- | | 400 to 449 W | 0.179 | 0.149 to 0.296 | 461 | 75 | | 450 to 499 W | 0.170 | 0.150 to 0.193 | 976 | 85 | | 500 to 549 W | 0.159 | 0.142 to 0.190 | 587 | 88 | | 550 to 599 W | 0.151 | 0.132 to 0.190 | 152 | 53 | | 600 W and up | 0.147 | 0.133 to 0.162 | 280 | 53 | Where the step between two medians is smaller than either class's middle half, the class barely separates the offers: pick one from each and either could be cheaper. Where one class's middle half sits wholly below the next one's, the gap is real. A class whose middle half is much wider than its neighbours' holds very different offers under one size. One reason the classes differ in more than size is further down. #### The same shop, two classes Medians mix shops. A shop that sells mostly big modules may simply be a cheap shop, which would make big modules look cheap for the wrong reason. So each shop outside the United States gets its own median price per watt per class, and two classes are compared only where a shop lists both. Read the third column against the second. A count near half of the shops listing both means the size makes no consistent difference inside a shop; a count near all of them means it does. A negative median difference means the bigger class is cheaper per watt. | Comparison | Shops listing both | Bigger class cheaper | Median difference | | --- | --- | --- | --- | | 600 W and up vs 450 to 499 W | 46 | 39 | -9 % | | 450 to 499 W vs 400 to 449 W | 64 | 37 | -5 % | #### Bigger classes, longer modules, different cells Some offers name a module precisely enough for us to match it to our catalogue, and its datasheet then shows what else changes with the class. PERC is an older cell technology than TOPCon and the other n-type cells; [TOPCon or PERC](https://comparepv.com/articles/topcon-or-perc) sets the two side by side. The table sets the smallest Polish class against the largest. Read the length for roof fit, and the PERC count against the matched offers for how much of each class is the older cell type. | Class (Poland) | Median length | PERC offers | Matched offers | | --- | --- | --- | --- | | 400 to 449 W | 1,762 mm | 18 | 58 | | 600 W and up | 2,382 mm | 0 | 75 | Where the two rows differ in length and in cell mix, the price gap between the classes is partly a gap between module generations. The extra watts are only part of it. #### Two modules, real offers The rows behind the medians look like this. I picked the two modules by one rule: the module with the most shop offers in our catalogue in the 450 to 499 W class when this was written, and the same for 600 W and up. Nobody paid for a place here. The most-offered module in the 450 to 499 W class when this was written: Cheapest current offers for [JA Solar JAM54D40-470/LR](https://comparepv.com/panel/ja-solar-jam54d40-470-lr), prices read 9 Oct 2026. | Shop | Market | Price | Availability | | --- | --- | --- | --- | | [PV Zenit](https://comparepv.com/go/65264) | Poland | 335.00 zł incl. VAT | In stock | | [Eco System Projekt](https://comparepv.com/go/181) | Poland | 339.00 zł incl. VAT | In stock | | [Solar-EM](https://comparepv.com/go/1383) | Poland | 341.00 zł incl. VAT | In stock | | [Megawat Elektrohurt](https://comparepv.com/go/1798) | Poland | 341.34 zł incl. VAT | In stock | | [PVhurt](https://comparepv.com/go/285663) | Poland | 366.49 zł incl. VAT | In stock | *Each price is the figure the shop printed, on its own side of VAT.* The most-offered module from 600 W up when this was written: Cheapest current offers for [Jinko Solar JKM620N-66HL4M-BDV](https://comparepv.com/panel/jinko-solar-jkm620n-66hl4m-bdv), prices read 9 Oct 2026. | Shop | Market | Price | Availability | | --- | --- | --- | --- | | [PV Zenit](https://comparepv.com/go/3204) | Poland | 406.00 zł incl. VAT | In stock | | [Panele-Sloneczne.com](https://comparepv.com/go/18049) | Poland | 336.00 zł net | In stock | | [Eco System Projekt](https://comparepv.com/go/189) | Poland | 435.00 zł incl. VAT | In stock | | [PVhurt](https://comparepv.com/go/3292) | Poland | 451.27 zł incl. VAT | In stock | | [TIM SA](https://comparepv.com/go/1112) | Poland | 500.73 zł incl. VAT | In stock | *Each price is the figure the shop printed, on its own side of VAT.* Each row prints the shop's own price, in its own currency and on its own side of VAT. For a price per watt, take the price without VAT and divide it by the rated power in the module name. The rows are ordered by the price before VAT in a common currency, so a net price can sit between two higher prices that include VAT; [gross or net shop prices](https://comparepv.com/articles/gross-or-net-shop-prices) explains why. ### What this means when you buy #### Pick the size for the roof, then shop inside it If the class medians sit closer together than the width of one class's middle half, choosing the offer does more than choosing the class. That's how I would shop: settle the module size the roof suits, then compare offers hard inside that size. [The same module in different shops](https://comparepv.com/articles/same-module-different-shop-price-spread) shows how far one module's price moves from shop to shop. #### A cheaper watt only helps if the module fits Bigger modules are longer; the length table above gives the medians, and [how big are modern solar panels](https://comparepv.com/articles/how-big-are-modern-solar-panels) covers the dimensions in full. On a small or broken-up roof, fewer large modules can leave more of it empty than more small ones would. You end up with fewer watts at a lower price per watt, which saves nothing. The [roof-fit selector](https://comparepv.com/tools/roof-fit-selector) counts how many modules of each size fit a roof, tells you which size gives the most kWp, and prints the cheapest offer we hold for each size. #### Mounting and labour are paid per module Part of the balance of system scales with the module count. Clamps and the time spent lifting and fixing each module are paid per module. Fewer, larger modules for the same array spread those costs over more watts. This data doesn't measure that, because the prices here are for modules alone. The effect grows with the job. On a large flat roof the module count runs into the hundreds, and every module brings its own share of racking and handling. ![Rows of solar modules covering a flat commercial building roof, seen from above beside a car park](https://comparepv.com/static/images/articles/commercial-roof-solar-array.webp) *A flat commercial roof covered with rows of modules; at this scale a few watts more per module changes the module count, racking and labour for the whole job. Image: [Esthee2010](https://commons.wikimedia.org/wiki/File:Solar_Panel_on_Rooftop_2.jpg), [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0).* #### Compare per watt, on the same tax basis A cheap listing with a lower rating can cost more per watt than a dearer one with a higher rating. Take a 420 W module at 80 EUR net: 80 / 420 = 0.190 EUR/W. A 500 W module at 90 EUR net works out at 90 / 500 = 0.180 EUR/W. The dearer listing buys the cheaper watt. Check whether the shop printed its price with or without VAT before you divide; our [offers list](https://comparepv.com/offers) marks it next to every price. Type in the offers you are weighing and the figure below ranks them the same way, against the market median before tax. **Rank offers by what a watt costs** Type the price and the rated power of the offers you are weighing and watch them re-rank by price per watt, with each one's gap to the cheapest. Divide each offer's price by its rated power in watts and rank the results, lowest first. A 400 W module at 72 EUR costs 0.180 EUR/W, a 450 W module at 78 EUR costs 0.173 EUR/W, and a 600 W module at 112 EUR costs 0.187 EUR/W. The 450 W module is the cheapest per watt, although the 400 W module has the lowest price: it buys fewer watts. The 400 W module costs 3.8 % more for every watt, and the 600 W module 7.7 % more. Interactive on the web page. The rated watts are a nameplate figure with a power tolerance around them, so two modules on the same label won't necessarily deliver exactly the same. #### Watts per square metre are a separate question A larger module isn't necessarily a more efficient one, since extra area adds watts by itself. If roof area is your limit, compare module efficiency instead. The [solar payback calculator](https://comparepv.com/tools/solar-payback-calculator) turns a price into a payback time, and the levelized cost of electricity prices the watt over the system's life. ### Limits of this data These are asking prices. A shop may sell below its listed price to installers or on bigger orders, and shipping isn't included. Pallets and multipacks are out of the pool, so for a full pallet the gap between classes may look different; [pallet or single module](https://comparepv.com/articles/pallet-or-single-module) compares the two. The class comes from the power the shop printed. Length and cell technology come from the manufacturers' datasheets in our catalogue, so they rest on matched offers only: compare the Matched offers column with the class's Offers count before you lean on them. The pool counts offers, not shops, so a shop with a long list of one size weighs more in that class's median. The same-shop comparison checks for that, but it rests only on the shops that list both classes. Prices are converted at the ECB reference rate of the day each offer was read. An exchange rate move can shift a non-euro market's figures without any shop changing a price. ## 01. Figures and denominators How the figures above were computed. Every figure is recomputed from the catalogue and the live shop offers when the page is served, and each one counts only the modules or offers that publish the value. The offers come from our crawler, which reads the public product pages of shops in several countries and keeps one current row per product page. A product page the crawler stops seeing drops out after a week, so the pool is the offers live when the page is served, not a price history. The pool is the same as in our article on price per watt by market: single modules (no pallets or multipacks) rated 400 to 800 W, with a price, and a price per watt between 0.05 and 2 EUR/W, which leaves 2,685 offers from 117 shops. Price per watt is the shop's price before VAT (before sales tax in the United States), converted to euro at the ECB reference rate of the day the offer was read, divided by the rated power the shop printed. The offers are split into five classes by that rated power: 400 to 449 W, 450 to 499 W, 500 to 549 W, 550 to 599 W, and 600 W and up. Medians and the 25th and 75th percentiles are continuous percentiles over the offers in each class; every offer counts once. Two scopes are reported. Poland is reported on its own because every class there held offers from at least 20 shops when this article was written; the Shops column gives the live count. The second scope is every market in the pool except the United States, whose price level is far above the European one and whose offers make up a large part of the smallest class, where they would move the median on their own. It keeps the other markets outside Europe. The same-shop comparison takes each shop outside the United States, computes its median price per watt in a class, and compares two classes only for shops that list both. Module length and cell technology come from the catalogue module an offer is matched to, so they cover matched offers only. | Figure | Value | Computed over | | --- | --- | --- | | Of those, shops whose 600 W and up median price per watt is lower | 39 | 46 shops | | Shops outside the United States listing both 450 to 499 W and 600 W and up | 46 | 46 shops | | Rooftop module offers in the price per watt pool | 2,685 | 2,685 offers | | Shops in the price per watt pool | 117 | 2,685 offers | | 400 to 449 W, all markets: offers from the United States | 132 | 593 offers | | Markets in the price per watt pool | 18 | 2,685 offers | | Same shop, 600 W and up against 450 to 499 W, price per watt difference, median | -9 % | 46 shops | | Shops outside the United States listing both 400 to 449 W and 450 to 499 W | 64 | 64 shops | | Of those, shops whose 450 to 499 W median price per watt is lower | 37 | 64 shops | | Same shop, 450 to 499 W against 400 to 449 W, price per watt difference, median | -5 % | 64 shops | ## 02. Related tools [Live shop offers](https://comparepv.com/offers) [Roof-fit selector](https://comparepv.com/tools/roof-fit-selector) [Solar payback calculator](https://comparepv.com/tools/solar-payback-calculator) ## 03. Related reading #### Solar panel price per watt by market [Open](https://comparepv.com/articles/solar-panel-price-per-watt-by-market) What a rooftop solar module costs per watt before tax in each market, from live shop offers, with the spread inside each country and what it means for a buyer. #### Pallet or single module: which is cheaper per watt? [Open](https://comparepv.com/articles/pallet-or-single-module) How much cheaper per watt is a pallet or multipack of solar panels than a single module? Live shop offers, same shop and same module, with counts. #### Gross or net: why two shop prices are not comparable [Open](https://comparepv.com/articles/gross-or-net-shop-prices) Which solar panel shops print prices with VAT and which without, market by market, and how to turn any shop price into a figure you can compare. #### The same module, different shop: how much prices differ [Open](https://comparepv.com/articles/same-module-different-shop-price-spread) How far apart shop prices sit for the exact same solar module, measured on live offers before VAT, and what stock status and shop habits add to the gap. #### TOPCon or PERC when buying today? [Open](https://comparepv.com/articles/topcon-or-perc) TOPCon or PERC? Efficiency, heat losses, warranted ageing and price per watt compared across our module catalogue and live Polish shop offers. #### How big are modern solar panels [Open](https://comparepv.com/articles/how-big-are-modern-solar-panels) Length, width, weight, watts per square metre and per kilogram for every module in our catalogue, and what the common formats mean for roofs and lifting. ## 04. Reference list 1. [European Central Bank, euro foreign exchange reference rates](https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html) --- Source: https://comparepv.com/articles/which-power-class-is-cheapest-per-watt