Thinking about installing solar but unsure what size system your home actually needs?
Choosing the right solar setup isn’t just about fitting as many panels as possible. An oversized system can cost more than necessary, while an undersized system may not deliver the savings or energy independence you’re hoping for.
Our Free Home Solar Calculator takes the guesswork out of the planning process by estimating the ideal solar panel system, battery size, installation cost and potential savings based on your home’s unique energy needs.
👉 Try the calculator here:
Why Solar System Size Matters
Every household uses electricity differently.
A family of five working and studying from home has very different energy requirements compared to a retired couple or someone living in a small apartment.
The right solar system depends on many factors, including:
- The size of your home
- Number of people living there
- Daily electricity usage
- Major appliances
- Heating and cooling
- Electric vehicle charging
- Future energy needs
- Roof orientation and shading
- Local climate
Rather than relying on averages, our calculator estimates a system tailored to your situation.
What the Home Solar Calculator Does
Instead of asking you to work through complicated formulas, the calculator guides you through a series of simple questions.
It estimates:
✔ Annual electricity consumption
✔ Recommended solar panel capacity
✔ Suggested inverter size
✔ Battery storage recommendation
✔ Estimated installation cost range
✔ Potential annual electricity savings
✔ Estimated payback period
✔ Lifetime savings
✔ Estimated carbon emissions reduction
The results are designed to help you understand what may suit your home before speaking with a professional installer.
How It Works
Using the calculator takes just a few minutes.
Step 1: Tell Us About Your Home
Enter details such as:
- Country
- House size
- Number of occupants
- Roof direction
- Roof shading
Step 2: Select Your Appliances
Choose the appliances you regularly use, including:
- Refrigerator
- Heat pump
- Air conditioning
- Washing machine
- Dryer
- Dishwasher
- Electric hot water
- EV charger
- Home office equipment
- Entertainment systems
Step 3: Add Your Electricity Usage
If you know your monthly electricity bill or average electricity consumption, enter it for improved accuracy.
If you don’t, the calculator estimates usage based on your home details and appliance selections.
Step 4: Choose Your Goals
Everyone has different priorities.
Maybe you want to:
- Reduce power bills
- Prepare for outages
- Install battery storage
- Reduce your environmental impact
- Future-proof your home for an electric vehicle
The calculator adjusts its recommendations accordingly.
Example Walkthrough
Let’s imagine a typical household.
Example Home
- Detached home
- Four occupants
- Moderate electricity use
- Heat pump
- Electric hot water
- Dishwasher
- Washing machine
- Clothes dryer
- Two people working from home
- Future electric vehicle planned
After entering this information, the calculator estimates:
| Estimate | Example Result |
|---|---|
| Annual Electricity Use | 9,800 kWh |
| Recommended Solar | 8.5 kW |
| Recommended Inverter | 8 kW Hybrid |
| Recommended Battery | 13.5 kWh |
| Estimated Annual Savings | Approximately NZ$2,400 |
| Estimated Installation Cost | NZ$18,000 to NZ$24,000 |
| Estimated Payback | Around 8 to 10 years |
Results shown above are examples only and will vary depending on location, electricity prices and household energy use.
Why We Built This Calculator
Many online solar calculators ask only for your roof size or electricity bill.
Real life is more complicated.
Your daily habits, appliance choices and future plans all affect the size of the solar system that may suit your home.
Our goal is to provide an easy-to-understand planning tool that helps you start informed conversations with installers.
Ready to Estimate Your Solar System?
Instead of guessing, let the calculator do the hard work.
Continue Your Solar Journey
If you’re exploring renewable energy, you may also find these EcoTIGA resources helpful:
- Should I Go Solar? Calculator
- Portable Power Calculator
- Can Renters Use Solar Power?
- Portable Power Stations Explained
- Home Energy Guides
Frequently Asked Questions
Is this solar calculator free?
Yes. The EcoTIGA Home Solar Calculator is completely free to use.
How accurate is the calculator?
The calculator provides educational estimates based on the information you enter. Actual system performance, installation costs and savings will vary depending on your location, equipment and installer.
Can I use this calculator if I don’t know my electricity usage?
Absolutely. The calculator can estimate household electricity consumption based on your home size, occupants and appliance selections.
Does the calculator recommend battery storage?
Yes. Where appropriate, it estimates a suitable battery size based on your electricity usage and goals.
Can renters use this calculator?
Yes. While some recommendations may be more suitable for homeowners, renters can still use the calculator to estimate energy needs and explore portable solar or battery solutions.
Does this calculator replace professional advice?
No. It is designed as an educational planning tool. Always consult a qualified solar installer before purchasing a system.
Final Thoughts
Installing solar is a significant investment, and choosing the right system starts with understanding your household’s energy needs.
Rather than relying on rough estimates, our Free Home Solar Calculator gives you a personalised starting point based on your home, appliances and lifestyle.
Whether you’re looking to reduce electricity bills, prepare for future energy needs or simply explore your options, the calculator can help you take the first step with confidence.