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There is no single “right” size for a home solar system. The right system depends on which appliances you want to power, how long you use them and when. These five steps will help you build a realistic picture before speaking to an installer.
Step 1: List your appliances
Write down every appliance you want the solar system to run. Each one has a power rating in watts (W), usually printed on a label or in the manual.
- Lighting (count the bulbs)
- TV, decoder and Wi-Fi router
- Refrigerator or freezer
- Water pump
- Laptops and phone chargers
- Iron, microwave or kettle (high-power — note these separately)
Step 2: Estimate your daily energy use
Energy is power multiplied by time. Multiply each appliance’s wattage by the hours you use it each day to get watt-hours (Wh). For example, a 100W appliance used for 5 hours uses 500Wh, or 0.5 kilowatt-hours (kWh).
Add everything up to get your approximate daily energy use. Remember that fridges cycle on and off, so their real consumption is lower than wattage × 24 hours.
Step 3: Identify what runs at the same time
Inverter capacity (measured in KVA or kW) limits how much power can be drawn at once. Add up the appliances likely to run together to estimate your peak load.
Appliances with motors — pumps, fridges and washing machines — draw a short surge of power when they start. The inverter must be able to handle these surges.
Step 4: Decide how much backup you need
Battery capacity, measured in kWh, determines how long your appliances can run without sunshine. Think about your evening usage and how long typical outages last in your area.
Not all of a battery’s rated capacity is usable — manufacturers specify a recommended depth of discharge to protect battery life.
Step 5: Size the solar panels
Panels need to produce enough energy to run your daytime loads and recharge the battery. Output depends on sunshine hours, panel orientation, roof angle and shading, so the same system can perform differently on different properties.
Why a professional assessment matters
Your own estimate is valuable preparation. A professional assessment then checks your appliance list, roof space and shading, and recommends an inverter, battery and panel combination that fits your needs and budget.
Written by
Synowatt Editorial Team
Practical guidance from the team at Synowatt Power & Solar Ltd, written to help Kenyan homes, businesses and institutions make informed energy decisions.
This article is general information. The right solar system for your property depends on a professional assessment of your energy needs and site.
Have questions about your solar options?
Talk to Synowatt Power & Solar Ltd about your property and energy needs — we’ll help you find a suitable solar solution.
