Free Tiny House Solar Calculator

Calculate your exact off-grid solar system requirements and get personalized product recommendations matched to your needs.

Updated March 2026

✨ New Feature: After calculating your system size, you'll get personalized DIY product recommendations, plus an All-in-One "Plug & Play" alternative.

⚠️ Important Safety Notice: This calculator provides estimates only. Always consult a licensed electrician and solar professional before designing or installing any system. Ensure compliance with NEC 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). Most locations in the US average between 3-6 hours in winter.

Average Daily Sun Hours:

Step 2: Fill Out Load Calculator

Select appliances from the dropdown to add them to your load list, or add a custom appliance. The calculator will automatically tally your daily power requirements.

-- Select an appliance -- LED Light Bulb (10W) Ceiling Fan (60W) MaxxAir / Roof Vent Fan (30W) Composting Toilet Fan (5W) 12V RV Water Pump (60W) Refrigerator (20 cu ft) (150W) 12V Compressor Fridge (60W) Microwave (1000W) Coffee Maker (900W) Induction Cooktop - 1 Burner (1500W) Mini-Split AC/Heat (600W) Space Heater (1500W) Electric Water Heater (1500W) Laptop Computer (60W) TV (55" LED) (90W) Wi-Fi Router (10W) Starlink Terminal (50W)

Appliance	Qty	Watts	Hours/Day	Total Wh/Day	Action

Total Watts (Peak Load) 0 W

Total Watt Hours / Day 0 Wh

Kilowatt Hours / Month 0.0 kWh

Optional: If you already know your total monthly kWh, override it here:

Step 3: Calculate System Size

Get your estimated solar array size, battery bank capacity (sized for 3 days of autonomy), inverter rating, and personalized equipment recommendations.

Your Estimated Off-Grid System

Solar Panel Array

0 W

Total watts needed to recharge batteries daily (includes 25% system loss buffer)

Battery Capacity

0 kWh

Sized for 3 days of backup autonomy (Lithium at 80% Depth of Discharge)

Inverter Size

0 W

Minimum continuous rating to run your peak simultaneous load

Charge Controller

0 A

Minimum MPPT rating (assuming a standard 24V or 48V battery bank)

Recommended DIY Equipment

Based on your inputs, here are the specific products recommended for your tiny house build.

*As an Amazon Associate, Dream Tiny Houses earns from qualifying purchases.

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Prefer a "Plug & Play" Alternative?

Skip the complex wiring. These All-in-One portable power stations feature built-in inverters, charge controllers, and batteries. Just plug in your solar panels and your appliances.

Frequently Asked Questions

How accurate is this calculator?

This calculator provides general estimates based on your inputs and typical off-grid system configurations, factoring in a 25% efficiency loss for real-world conditions. Actual requirements vary based on your specific appliances, wire gauge resistance, climate, and panel shading. Always consult a licensed solar professional for final design.

Why size for winter sun hours?

Winter typically has the lowest sun hours. 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 (like air conditioning).

What is battery autonomy?

Battery autonomy refers to how many days your battery bank can power your home without any solar input (e.g., during rain or heavy clouds). This calculator uses 3 days of autonomy, which is the industry standard for off-grid systems.

Should I use all-electric appliances?

Generally, no. Most successful off-grid tiny homes use propane or wood for major heating loads (cooking, water heating, space heating). Heating with electricity (like electric water heaters or space heaters) draws massive amounts of power, requiring extremely large and expensive solar arrays.

What's the cost of an off-grid system?

A full off-grid system typically costs $3,000 to $15,000+ depending on whether you DIY or hire a professional, and the quality of your batteries (Lithium vs Lead Acid). Our Amazon recommendations provide current market pricing baselines.

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