What Size Inverter Do I Need for My House in Nigeria? A Simple Sizing Guide

The most common solar mistake in Nigeria is buying the wrong size of inverter. Too small, and it trips every time the fridge compressor starts. Too big, and you have spent money you did not need to. The good news is that sizing an inverter is simple arithmetic.

Our solar calculator does all of this for you, but here is exactly how it works, so you can check any quote you receive.

Step 1: Add up your appliance wattage

List everything you want running on solar at the same time. Use the wattage on the appliance label, or these typical figures:

Appliance	Typical watts
LED bulb	12W each
Standing or ceiling fan	70W each
TV and decoder	120W each
Laptop or desktop	90W each
Wi-Fi router or Starlink	60W
Fridge	150W (compressor cycles)
Chest freezer	250W (compressor cycles)
1.5HP inverter AC	about 1,100W each
1HP water pump	750W (short runs)
Washing machine	500W per cycle
Microwave or pressing iron	about 1,000W (brief use)

Example, a 3-bedroom flat: 12 bulbs (144W) + 4 fans (280W) + 2 TVs (240W) + 2 laptops (180W) + router (60W) + fridge (150W) + freezer (250W) + pump (750W) = 2,054W.

Step 2: Add 25% headroom to get the inverter size

An inverter running near 100% load runs hot and wears out early. Motors in fridges, freezers and pumps also draw a surge when they start. Multiply your total by 1.25:

2,054W × 1.25 = 2,568W, so you need at least a 2.6kW inverter. In practice that means a 3.2kW or 4kW unit.

kVA or kW: which number matters?

Many inverters in Nigeria are sold in kVA. kVA is "apparent" power. kW is the real power your appliances use. For most home inverters, kW ≈ kVA × 0.8, so a 5kVA inverter delivers about 4kW. Always compare inverters by kW.

Step 3: Size the battery for your backup hours

The inverter decides what you can run. The battery decides how long you can run it without grid power or sun. Appliances do not draw full power all the time, so use the average load:

Battery kWh = average watts × backup hours ÷ 1,000 ÷ 0.9

The 0.9 accounts for the 90% usable depth of discharge of a LiFePO4 lithium battery. For our 3-bedroom example, 8 hours of night backup works out to about 7.3kWh of battery, or two 5kWh lithium batteries.

24V or 48V?

If you need more than about 4kWh of storage, choose a 48V system. A 48V system moves the same power at half the current, so it uses thinner cables, wastes less energy and works with modern 48V lithium batteries. That is why our calculator recommends a 6kW 48V inverter for this 3-bedroom flat, even though 2.6kW would carry the load: the battery bank needs 48V.

Step 4: Count your solar panels

Panels must run your daytime load and refill the battery before sunset. South-west Nigeria averages about 4.5 peak sun hours a day, and heat and dust cut panel output by around 25%. So:

Panel watts = (night kWh + daytime kWh) × 1,000 ÷ (4.5 × 0.75)

With 580W bifacial panels, our 3-bedroom example needs about six panels.

Quick sizing guide by home type

• Mini flat or shop (lights, fans, TV, laptop, fridge): about 630W peak, so a 3.2kW 24V inverter.
• 3-bedroom flat (with freezer and pump): about 2kW peak, so a 4kW to 6kW inverter depending on battery size.
• Duplex with two 1.5HP ACs: about 5.1kW peak, so an 8kW hybrid inverter.
• Small office (8 laptops, 2 ACs): about 3.8kW peak, so a 6kW 48V inverter.

See how much each of these costs fully installed in our solar installation cost guide.

Inverters we stock

Three sizing mistakes to avoid

1. Sizing for everything at once. You will rarely run the pump, microwave and iron together. Size for what genuinely overlaps.
2. Putting a non-inverter AC on solar. A conventional AC can draw double the power of an inverter AC. Switch to inverter ACs before you go solar.
3. Buying the inverter first and the battery later "when money comes". A 24V inverter cannot use a 48V lithium battery. Plan the whole system together.

Ready to size your home? Use the IVOLTE solar calculator, then book a free site survey with our engineers in Ota, Lagos or Ogun.