Free Tiny House Solar Calculator + Product Recommendations
Calculate your exact off-grid solar system requirements and get personalized product recommendations matched to your needs. This free calculator estimates solar panels, battery capacity, inverters, and charge controllers for your tiny house, then recommends specific products you can purchase to build your system.
New Feature: After calculating your system size, you'll get personalized product recommendations with real pricing, specifications, and direct purchase links. No more guessing which products to buy!
Free calculator with product recommendations • Updated November 2025
How to Use This Calculator:
- Enter Your Average Sun Hours - Use local climate data
- Add Your Appliances - Select from templates or add custom items
- Calculate System Size - Get your solar, battery, and inverter requirements
- View Product Recommendations - See specific products matched to your calculated needs
Pro Tip: After calculating, scroll down to see our curated product recommendations with pricing, specs, and purchase links. We match products specifically to your system size!
Important Safety Notice
This calculator provides estimates only. Always consult a licensed electrician and solar professional before designing or installing any electrical or solar system. Improper installation can cause fire, injury, or death. Ensure compliance with NEC 2023 and local building codes.
Step 1: Enter Your Average Sun Hours
Enter the average sun hours per day in your area during the darkest month (typically winter). You can find this data using the NREL PVWatts Calculator or by consulting with local solar installers.
How many Sun Hours a day do you average in the darkest month?
We'll use your winter low sun hours to size your PV array. Keep in mind your exact needs may vary depending on how your system will be used. Most locations in the US average between 3-6 hours in winter.
Step 2: Fill Out Load Calculator
Fill out the table below to estimate energy usage. We've included common household appliances found in off-grid homes. Try to account for everything, keeping in mind that off-grid homes should use efficient appliances, and the major heating loads (water & air heating) are usually not electric.
Solar Load Calculator
| Appliance | Quantity | Watts | Hours/Day | Wh/Day | Remove Appliance |
|---|
If you already have your monthly kWh total, you can enter it here:
Step 3: Calculate System Size & Get Product Recommendations
We'll estimate your off-grid system size based on the appliances and energy usage you entered. After calculation, you'll receive personalized product recommendations matched to your exact system requirements.
What You'll Get:
- Exact solar panel wattage and quantity needed
- Battery bank capacity for 3 days backup
- Inverter size matched to your peak load
- Charge controller specifications
- Specific product recommendations with pricing and purchase links
Add at least one appliance or enter your kWh/month to see recommendations
Frequently Asked Questions
Do I really get product recommendations after calculating?
Yes! After you calculate your system size, you'll automatically see personalized product recommendations for solar panels, batteries, inverters, and charge controllers matched specifically to your calculated requirements. We show you the exact products you need with real pricing, specifications, and direct purchase links. This takes the guesswork out of building your off-grid system.
How accurate is this calculator?
This calculator provides general estimates based on your inputs and typical off-grid system configurations. Actual requirements vary based on your specific appliances, usage patterns, climate, and local sun exposure. Always consult a licensed solar professional for final design and installation.
Why size for winter sun hours?
Winter typically has the lowest sun hours, so sizing your system for winter ensures you'll have adequate power year-round. During summer, you'll have excess capacity which helps extend battery life and handle unexpected loads.
What is battery autonomy?
Battery autonomy refers to how many days your battery bank can power your home without solar input. This calculator uses 3 days of autonomy, which is standard for off-grid systems to handle cloudy periods. You may want more in areas with frequent extended cloudy weather. Learn more about battery storage and system design.
Should I use all electric appliances?
No. Most successful off-grid homes use propane or wood for major heating loads (cooking, water heating, space heating). Heating with electricity requires very large (and expensive) solar and battery systems. Reserve electricity for lighting, electronics, and refrigeration. Check out our energy-efficient kitchen appliances and LED lighting options.
What about backup generators?
Many off-grid systems include a backup generator for extended cloudy periods or high-demand situations. A properly sized solar system should minimize generator use, but having one provides peace of mind and can reduce required battery bank size. Browse our recommended generators for tiny homes.
What's the cost of an off-grid system?
Off-grid solar systems typically cost $3-5 per watt installed, so a 5kW system would cost $15,000-$25,000. Batteries add $5,000-$15,000 depending on capacity and type. DIY installations can reduce costs by 30-50%, but require electrical knowledge and proper permitting. Our product recommendations show current prices for components so you can budget accurately.
Why do the product links say "affiliate"?
We earn a small commission when you purchase through our affiliate links, at no extra cost to you. This helps us keep this calculator and all our tools completely free. We only recommend products we trust and would use in our own tiny house builds. Your support through these links helps us continue providing free resources to the tiny house community.