Solar Panels and Roof Renovation Combined: The Guide for Hannover and the Region

If your house needs a roof renovation, that’s the best moment for a solar system. Planning solar panels and the roof renovation together means the scaffolding only goes up once, you avoid removing and refitting the modules later, and you meet the solar obligation that has applied to many roof renovations in Lower Saxony since 2025. Here you’ll learn what the law requires, which funding is available in the Hanover region and how to coordinate both projects sensibly.

Planning a roof renovation and want to include solar from the start? Request your free, no-obligation quote now.

Solar Panels and Roof Renovation: Key Points at a Glance

• Planning together saves money: scaffolding and site setup are needed only once, and the modules don’t have to be removed later for a renovation.
• Solar obligation: in Lower Saxony, a fundamental roof renovation can trigger a PV obligation (Section 32a of the Lower Saxony Building Code, NBauO).
• Funding: the Hanover Region pays €150 per m² of module area above the minimum and €50 per m² of roof insulation, and the federal government funds insulation at 15%. On top of that, there’s 0% VAT on the PV system.
• Same service life: a newly covered roof and a PV system both last for decades, which is why doing them at the same time works so well.

Why Solar Panels and a Roof Renovation Belong Together

A PV system stays on the roof for 25 years or more. If you install it on a roof that needs renovating in a few years, you’ll have to have the system removed and refitted later, which costs scaffolding, labour and yield. Conversely, it’s frustrating to open up a freshly renovated roof again for installation.

If you plan both together, the scaffolding goes up only once. The roof hooks can be fitted directly while the roof is being covered, and the cable routes are planned in at the same time. Your roofer carries out the roof renovation itself. We plan and install the PV system and coordinate the schedule with the roofer.

PV Obligation for Roof Renovations in Lower Saxony

Since 1 January 2025, the solar obligation in the Lower Saxony Building Code (Section 32a NBauO) has applied not only to new buildings but also to existing buildings when the roof covering is fundamentally renewed. It applies to residential and non-residential buildings. The key points:

• The obligation is triggered by a complete renewal of the roof covering down to the water-bearing layer, not by minor repairs.
• It applies from 50 m² of renewed roof area.
• In that case, at least half of that roof area must be covered with a solar system for generating electricity. Areas used for solar thermal count towards this.
• There are exemptions, for example where heritage protection stands in the way or the area is unsuitable.

It’s best to clarify the exact exemptions and required evidence early with the building authority or your architect. Importantly, plan the PV system as part of the renovation from the start.

Funding in the Hanover Region

• Hanover Region, Dach-Solar: €150 per m² of module area above the legal minimum area. Dach-Solar, however, is only available with simultaneous roof insulation and from a calculated grant of €4,000. To calculate the minimum, 35% is deducted from the roof area (50% for flat roofs), and 50% of the remaining area must be covered. Funding is capped at 90% of PV costs, and batteries are not eligible. Roof insulation gets an extra €50 per m², but only together with the PV system and capped at 80% of the PV grant. Electrical work on residential buildings adds up to €1,000. You must apply before placing the order.
• proKlima DachVollToll: in Hanover, Hemmingen, Laatzen, Langenhagen, Ronnenberg and Seelze, proKlima funds fully covered roofs on residential buildings while funds last, if you apply before placing the order.
• Federal, insulation: the federal funding for efficient buildings (BEG individual measures, BAFA) subsidises roof insulation at 15% of eligible costs, up to €30,000 of eligible costs per residential unit and year. An energy-efficiency expert must be involved. The rules for the bonus with an individual renovation roadmap (iSFP) changed on 21 July 2026, so check them before applying. Also check beforehand whether BAFA and the Region can be combined for the same insulation.
• PV system: 0% VAT on supply and installation on residential buildings, and financing through the KfW 270 loan. There is no federal grant for private PV systems.

Worked Example: Region Funding for PV and Insulation

A 100 m² gable roof is re-covered and insulated. After deducting 35%, 65 m² remains, so the minimum area is 32.5 m². If 50 m² of modules are installed, 17.5 m² are eligible, giving about €2,600. For insulating 100 m², it would be €5,000, capped at 80% of the PV grant, i.e. about €2,100. Together, the Region contributes about €4,700 in this example, above the €4,000 minimum grant, plus the flat rate for electrical work on residential buildings.

You’ll find an overview of all programmes under solar funding in Hanover.

In-Roof or On-Roof?

On-roof systems are mounted above the new roof covering. They’re the standard solution: inexpensive, proven and well ventilated. During a renovation, the roof hooks can be fitted while the roof is being covered. We install using the K2 Systems mounting system.

In-roof systems replace part of the roof covering, with the modules sitting flush with the roof. They look more refined and can be an option for older or listed buildings. Which roof pitch and which roof covering are possible is specified by the manufacturer of the in-roof system. In-roof systems generally cost more per kWp than on-roof systems: for the in-roof system, we calculate approx. €250–400 per kWp. During a renovation, the extra cost is somewhat lower, because the modules replace part of the roof covering. We install both: on-roof systems with the K2 Systems mounting system and in-roof systems with the GSE In-Roof System or the K2 In-Roof System, where the modules replace part of the roof covering. We check whether in-roof suits your roof during the on-site visit and coordinate the work with your roofer. Systems, prices and the installation process are explained in detail in our guide to in-roof solar panels: costs and systems. Read more about mounting types under rooftop solar systems.

What Does the Combination Deliver Financially?

As a guide, the PV system itself costs about €1,450–1,750 per kWp, so a 10 kWp system costs about €14,500–17,500 without a battery. Planning it together with the renovation also saves the cost of separate scaffolding and later removal. If an existing system has to be removed and refitted for a later renovation, providers quote from about €1,000, and considerably more depending on system size and scaffolding. In the Hanover region, the system produces about 893 kWh per kWp per year. Without a battery, a typical household uses 25–35% of the solar power itself, and 55–70% with a battery. Every self-consumed kilowatt-hour saves you grid electricity, which is 37 cents at an assumed price of 37 ct/kWh. You’ll find an honest worked example under is solar worth it?

Want to know how the PV system will fit your renovated roof? Request your free, no-obligation quote now.

Older Roofs: Asbestos, Structure and Roof Condition

• Asbestos: many roofs and outbuildings from before the 1990s have corrugated asbestos-cement sheets. Mounting on them is not allowed. They must first be removed by an approved specialist company, after which the new roof area can be used for PV.
• Structure: a PV system adds about 15 to 25 kg per m² to the roof. For older roof structures, we check beforehand whether the load capacity is sufficient.
• Roof condition: a PV system lasts 25 years or more. The covering underneath should last at least as long; otherwise, now is the right time to renovate.

The Process: Coordinating Your Roof Renovation and Solar Panels

1. Check the roof: the condition of the covering, insulation and load-bearing capacity, ideally with your roofer and us together.
2. Plan together: layout, roof hooks, cable routes and schedule. Check the solar obligation and the structure.
3. Apply for funding: always before work begins or before placing the order.
4. Renovate the roof: by your roofer, who fits the roof hooks for the PV system at the same time.
5. Install the PV system: by our own certified technicians, including registration with the grid operator and in the Market Master Data Register.

At PVPro Solar, you get a free initial consultation with roof analysis and yield forecast, and a fixed-price quote with modules from AIKO, JA Solar or Longi, a Fronius inverter and an optional BYD battery. You pay using the 30/70 model.

Request your free, no-obligation quote now, or call us on +49 511 3360603 or message us on WhatsApp at +49 176 2399 8536.

Frequently Asked Questions About Solar Panels and Roof Renovation

Note: This article provides a general overview (as of October 2026) and does not replace tax or legal advice.