What Factors Affect the Cost of a Solar Installation?

One of the most common questions we get at RenovaEnergy is: Why does the price of a solar installation vary so much? The truth is, there’s no single price tag—every system is custom-designed. In this guide, we explain the main cost drivers and how to know if you’re getting a fair deal.

Key Factors That Influence the Final Cost

• Annual electricity usage: The more energy you use, the more panels you’ll need.
• Roof size and orientation: These affect how many panels fit and how efficiently they generate energy.
• Panel type: High-efficiency or premium panels are more expensive than standard ones.
• Inverter quality: Its size and technology play a big role in system performance and cost.
• Battery storage: Adding a battery can significantly increase the total investment.
• Installation difficulty: A simple flat roof is cheaper than a steep or complex one.

How Much Does Solar Cost in 2025?

Prices have dropped in recent years, but depend heavily on system size and extras:

• Small system (3 kW): €4,000 – €5,500
• Medium system (5 kW): €6,000 – €8,000
• System with battery: €10,000 – €14,000

What Should a Complete Quote Include?

At RenovaEnergy, our quotes are always turnkey and transparent. They include:

• Solar panels, inverter, and mounting structure
• Custom technical design
• Installation and system certification
• Paperwork for government grants and grid connection
• Monitoring system

How to Know If You’re Getting a Good Deal

The cheapest offer isn’t always the best. What matters is quality, guarantees, and long-term return. RenovaEnergy helps you understand what you’re paying for and why.

Wondering how much your system should cost? Request a free quote from us and we’ll guide you without obligation.

The Best Solar Self-Consumption Tariff in 2025

If you already have solar panels or are planning to install them, there’s one essential question: Which electricity tariff gives you the most savings? At RenovaEnergy, we guide you through finding the best plan to make your solar installation even more profitable.

What should a good solar tariff include?

Not all energy plans are designed for solar users. A good self-consumption tariff should:

• Offer a fair rate for excess energy you feed into the grid
• Include a competitive kWh price for non-solar hours (nighttime, winter)
• No hidden costs, fees, or forced service bundles

How does surplus compensation work?

With simplified compensation, the value of unused solar energy is deducted from your electricity bill. But rates vary by provider, and some set limits on monthly credits.

Should I choose a fixed, variable, or time-of-use tariff?

• Fixed-rate: Stable and predictable, good for consistent consumption patterns
• Variable/indexed rate: Follows the real market price, which can offer savings—but less predictability
• Time-of-use (TOU): Great if you can shift your usage to off-peak hours

If you have a solar battery, TOU tariffs can help you charge when energy is cheapest and use it when rates are high.

Common mistakes to avoid

• Choosing a plan just because of a low kWh price without checking compensation
• Paying for added services you don’t need
• Not reviewing your tariff annually—many increase after the first year

Still don’t have solar panels?

We’ve got you covered. At RenovaEnergy, we design your solar system and recommend the best tariff to match it, so you save from day one.

Need help choosing the best solar plan?

RenovaEnergy analyzes your consumption, solar production, and the current energy market to propose the best self-consumption tariff for your home in 2025.

Want a free customized comparison? Contact us with no obligation.

How Much Energy Do Solar Panels Produce on Cloudy Days?

One of the most frequent questions we hear from future solar users is: Do solar panels work when the sky is cloudy? At RenovaEnergy, we explain how cloud cover affects solar performance and why solar power is still efficient even without direct sunlight.

Do solar panels work on cloudy days?

Yes. While their output is lower, solar panels continue generating electricity thanks to diffused sunlight—light that passes through the clouds.

How much does production decrease?

The loss of performance depends on how dense the clouds are. In general:

• Lightly cloudy: 60% to 80% of normal production
• Moderately overcast: 30% to 50% of normal output
• Very cloudy or rainy: 10% to 25%, but rarely zero

Do all panels perform the same in cloudy weather?

No. Some panels, such as monocrystalline models, are more efficient in low-light conditions. The inverter and monitoring systems also play a key role in maximizing performance.

How does this affect savings?

If you live in an area with frequent cloudy days, your annual production might drop slightly. But in most parts of Spain, the impact is minimal and annual output remains high enough to ensure profitability.

What if I have a solar battery?

Batteries help stabilize your energy use. You can store excess electricity from sunny days and use it when production drops due to weather.

Bottom line? Clouds aren’t a problem

Solar panels don’t need direct sun to work. While performance may decrease on cloudy days, they still generate valuable electricity. A properly designed system will account for this and ensure reliable output year-round.

Curious if your location is a good fit for solar? RenovaEnergy will assess your site, consumption habits, and sun exposure to give you a clear answer.