{"id":12562,"date":"2025-10-31T23:26:34","date_gmt":"2025-10-31T22:26:34","guid":{"rendered":"https:\/\/pvprosolar.de\/?p=12562"},"modified":"2026-10-13T19:48:56","modified_gmt":"2026-10-13T17:48:56","slug":"solar-system-calculator","status":"publish","type":"post","link":"https:\/\/pvprosolar.de\/en\/solar-system-calculator\/","title":{"rendered":"Solar Calculator: How to Calculate Yield, Costs and Payback"},"content":{"rendered":"

What will a solar system on your roof produce, what will it cost and when will it pay for itself? You don’t need a complicated solar calculator for that. With five simple steps and a few guide values, you can estimate the key figures yourself. Here we show you how, which free online calculators are genuinely reliable, and where every online calculation reaches its limits.<\/p>\n

Want an accurate calculation for your roof? Request your free, no-obligation quote now<\/a>. We’ll prepare a free yield forecast using your real data.<\/p>\n

It’s quicker with our solar calculator<\/a> (in German):<\/strong> enter your household consumption, system size and, if you like, a battery, heat pump and EV, and you immediately see how much you save and how much of your electricity you cover yourself. No sign-up, no phone number.<\/p>\n

Solar Calculator: Key Facts at a Glance<\/h2>\n\n\n\n\n\n\n\n\n\n\n
Calculation step<\/th>\nGuide value for the Hanover region<\/th>\n<\/tr>\n<\/thead>\n
Roof area per kWp<\/td>\napprox. 5\u20136 m\u00b2<\/td>\n<\/tr>\n
Annual yield<\/td>\napprox. 893 kWh per kWp, 10 kWp just under 9,000 kWh<\/td>\n<\/tr>\n
Self-consumption<\/td>\napprox. 25\u201335% without a battery, approx. 55\u201370% with one<\/td>\n<\/tr>\n
Value of a kWh<\/td>\nused yourself approx. 37 ct, fed in approx. 7.70 ct<\/td>\n<\/tr>\n
Costs<\/td>\napprox. \u20ac1,450\u20131,750 per kWp without a battery<\/td>\n<\/tr>\n
Payback for 10 kWp<\/td>\napprox. 10\u201312 years without a battery, approx. 12\u201314 years with one<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Calculate Your Solar System Yourself in 5 Steps<\/h2>\n

Step 1: Determine the System Size<\/h3>\n

The size depends mainly on your usable roof area. As a rule of thumb, with today’s modules you need about 5 to 6 m\u00b2 of roof area per kWp. For 10 kWp, that’s roughly 50 to 60 m\u00b2. With a heat pump or an EV, it usually pays to cover the entire suitable area.<\/p>\n

Step 2: Estimate the Annual Yield<\/h3>\n

Formula:<\/strong> system size (kWp) \u00d7 specific yield (kWh per kWp) = annual yield<\/p>\n

In the Hanover region, we calculate about 893 kWh per kWp per year. A south-facing roof with a 30 to 35 degree pitch tends to be higher, while an east-west roof or shading tends to be lower. Example: 10 kWp \u00d7 893 kWh = just under 9,000 kWh a year.<\/p>\n

Step 3: Estimate Self-Consumption<\/h3>\n

Formula:<\/strong> annual yield \u00d7 self-consumption rate = solar power used on site<\/p>\n

Without a battery, a typical household uses about 25\u201335% of its solar power itself, and about 55\u201370% with a battery. Importantly, the power you use yourself can never exceed your annual consumption. If the system generates far more than you use, the rate will be at the lower end.<\/p>\n

Step 4: Calculate the Annual Benefit<\/h3>\n

Formula:<\/strong> self-consumed power \u00d7 electricity price + power fed in \u00d7 feed-in tariff = benefit per year<\/p>\n

Use your own electricity price from your bill. In our examples, we assume 37 ct\/kWh. Since 1 August 2026, new systems up to 10 kWp with partial feed-in have earned about 7.70 ct\/kWh for power fed into the grid.<\/p>\n

Step 5: Calculate the Payback Period<\/h3>\n

Formula:<\/strong> purchase cost \u00f7 benefit per year = payback period in years<\/p>\n

As a guide to costs, we calculate about \u20ac1,450\u20131,750 per kWp without a battery, so about \u20ac14,500\u201317,500 for 10 kWp. With a BYD HVS 10.2 battery, it’s about \u20ac22,200\u201326,700.<\/p>\n

Worked Example: 10 kWp in the Hanover Region<\/h2>\n

A four-person household uses 4,800 kWh a year. Assumed electricity price 37 ct\/kWh, feed-in tariff 7.70 ct\/kWh, no electricity price increase:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
Calculation step<\/th>\nWithout battery<\/th>\nWith battery<\/th>\n<\/tr>\n<\/thead>\n
Annual yield (10 kWp \u00d7 893 kWh)<\/td>\napprox. 8,900 kWh<\/td>\napprox. 8,900 kWh<\/td>\n<\/tr>\n
Self-consumed<\/td>\napprox. 2,700 kWh (30%)<\/td>\napprox. 4,000 kWh (45%)<\/td>\n<\/tr>\n
Savings (\u00d7 37 ct)<\/td>\napprox. \u20ac990<\/td>\napprox. \u20ac1,490<\/td>\n<\/tr>\n
Feed-in (rest \u00d7 7.70 ct)<\/td>\napprox. \u20ac480<\/td>\napprox. \u20ac380<\/td>\n<\/tr>\n
Benefit per year<\/td>\napprox. \u20ac1,470<\/td>\napprox. \u20ac1,870<\/td>\n<\/tr>\n
Cost (guide value)<\/td>\n\u20ac14,500\u201317,500<\/td>\n\u20ac22,200\u201326,700<\/td>\n<\/tr>\n
Payback period<\/td>\napprox. 10\u201312 years<\/td>\napprox. 12\u201314 years<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Why only 45% with a battery? The system generates almost twice as much power as the household uses. You’ll find more explanation of this example under is solar worth it?<\/a><\/p>\n

Want this calculation with your own figures? Request your free, no-obligation quote now<\/a>.<\/p>\n

Our Solar Calculator<\/h2>\n

With the PVPro Solar calculator<\/a> (in German), the steps above are calculated automatically. You start with a few details, annual consumption, PV output, battery, electricity price and feed-in tariff, and can then refine everything: people in the household, roof pitch, roof type and orientation, a heat pump with living area and building condition, and an EV with mileage and charging strategy. The result shows your annual savings and how much of your electricity, heat pump and EV demand you cover with solar power. You don’t need to sign up or give a phone number.<\/p>\n

Independent Online Calculators for Cross-Checking<\/h2>\n