How to Choose the Right Solar Panel for Your Home——Building an Efficient Solar System
If you’re researching how to build your own solar power system, you’ve already moved beyond the basic idea of “saving on electricity bills.” You’re now thinking about energy independence.
As the starting point of any solar system, the solar panel you choose directly determines the efficiency and performance of everything that follows. In this guide, we’ll walk you through the key parameters that matter most—so you can make a confident, professional decision.
1. The First Step: Define Your Core Needs
Before comparing products, it’s important to understand two concepts that are often confused:
● Peak Power (W)
Measured in watts (W), peak power indicates the maximum output of a solar panel under Standard Test Conditions (25 °C, 1000 W/m²).
Think of it like the maximum horsepower of an engine.
● Energy Generation (kWh)
Measured in kilowatt-hours (kWh), this is what truly matters: how much electricity the system produces over time, such as per day or per year. It depends on the power of your solar panels and the amount of sunlight available at your location.
Practical tip
Before designing your system, check the average daily peak sun hours in your location.
(You can check local sunshine data here: https://weather-and-climate.com/)
Example: Hamburg, Germany
Hamburg receives approximately 1,572 hours of sunshine per year, which translates to about 4.3 peak sun hours per day on average.
Under ideal conditions, a 2 kW solar system could generate up to:
4.3 × 2 = 8.6 kWh per day
By comparing this figure with your household’s daily electricity consumption, you can estimate how much solar capacity you need to cover your energy needs.
Monthly hours of sunshine in Hamburg. (Source:WEATHER & CLIMATE)
⚠️ Important note:
Sunlight varies significantly by season. Summer production is much higher, while winter output can drop sharply. When planning a solar system, don’t rely solely on annual averages—evaluate monthly and seasonal sunlight data to set realistic expectations.
2. Understanding Solar Panel Performance: Key Technical Metrics
Real-world conditions rarely match laboratory test environments. That’s why, beyond rated power, several performance coefficients are critical. Understanding them allows you to predict how a panel will actually perform over time.
I. Conversion Efficiency
Efficiency indicates how effectively a panel converts sunlight into electricity per unit area.
Higher efficiency means more power from the same roof or balcony space—a key advantage when space is limited.
Today’s mainstream solar panels typically offer 19% – 23% efficiency. Within this range, real-world differences are usually modest.
II. Temperature Coefficient
Solar panels are rated at 25 °C, but in real use, they heat up.
The temperature coefficient shows how much power output drops for every 1 °C increase in panel temperature (e.g. −0.29%/°C or −0.34%/°C).
The smaller the absolute value, the more stable the performance in hot conditions.
In warmer climates, temperature coefficient often has a greater impact on actual energy yield than peak wattage.
III. Power Degradation Rate
Solar panels slowly lose output over time.
Pay attention to:
● First-year degradation
● Remaining power after 10, 20, or 25 years
Lower degradation means higher lifetime energy production—and better long-term return on investment.
3. Technology Choices: P-Type, N-Type, and Thin-Film Panels
The market has evolved far beyond the old “monocrystalline vs. polycrystalline” debate. Today, most panels fall into three main categories:
|
Technology |
Key Advantages |
Best Use Cases |
|
P-Type Monocrystalline (PERC) |
Mature technology, strong reliability, cost-effective |
Most residential and commercial installations; a safe, proven choice |
|
N-Type Monocrystalline (TOPCon / HJT) |
Higher efficiency, lower degradation, better low-light performance |
Users seeking maximum long-term output, limited space, higher budgets |
|
Thin-Film (e.g. CdTe) |
Excellent high-temperature performance, fast low-light response, uniform appearance |
Utility-scale projects or architecturally integrated designs |
Our view:
For new installations, if budget allows, N-type monocrystalline panels are worth prioritizing.
With lower first-year degradation (around 1%) and linear degradation thereafter, they deliver higher total energy output over a 25-year lifespan, resulting in lower electricity costs over time.
4. System Compatibility: Don’t Let Power Go to Waste
Your solar panels must work in harmony with the rest of your system—especially the inverter.
1. Understanding “Over-Sizing”
To improve overall efficiency, it’s common to install solar panels with 10%–30% more total capacity than the inverter’s rated power. This practice, known as over-sizing, allows the inverter to operate at optimal levels for more hours per day, increasing total energy production.
2. Precise Voltage and Current Matching
Ensure that:
● The maximum string voltage stays within the inverter’s MPPT range—especially in cold conditions, when voltage rises
● The operating current does not exceed the inverter’s maximum input
Ignoring these limits can damage the inverter and void warranties.
5. Know the Rules: Local Solar Regulations Matter
Before placing an order, spend 10 minutes checking your local regulations. Otherwise, your system may face grid connection issues—or even fines.
Example: Germany
Germany classifies balcony solar systems as “small plug-in photovoltaic devices”, with simplified rules:
● Key limits:
○ Inverter AC output ≤ 800 W
○ Total panel capacity ≤ 2 kW
● Major advantage:
○ No complex approval process—only simple registration required
Our Integrated Solution
Still worried about compatibility? That’s exactly why we advocate an integrated, all-in-one approach.
● Micro Inverter
MARSTEK SATRUN-M Micro Inverter equip with 4 MPPT for Max, supports output from 800 W to 2000 W. Meet the solar power demands of the vast majority of households.
With the MARSTEK APP, users can monitor system performance in real time. Plug ＆ play installation, feature a universal MC4 interface, ensuring compatibility with most solar panels and batteries on the market.
● Energy Storage System
MARSTEK VENUS A features an All-in-One Design integrating Inverter and LFP Battery.
● 4 MPPT for Max, Up to 2.4 kW solar input
● Stackable scale up to 12.72 kWh
● Supports Marstek App control
● Plug & Play Design, Quick setup in just 5 minutes
● AI-driven charging schedules to maximize self-consumption and reduce electricity bills
Simply connect the solar panels—the system automatically identifies and optimizes operating conditions for true Plug ＆ Play efficiency.
