A low-cost solar home cooling system can be an excellent option for reducing energy consumption and cooling costs. Here are a few cost-effective solutions that combine solar energy and passive cooling techniques:

1. Solar-Powered Attic Fans

Solar-powered attic fans are a great way to reduce indoor temperatures by venting hot air out of the attic. They are relatively inexpensive, easy to install, and can significantly lower the temperature in your home, especially during hot summer months. By improving attic ventilation, they also help to prevent the buildup of heat in the living space.

2. Solar-Powered Air Conditioners

While traditional air conditioners are costly to run, solar-powered air conditioners use solar panels to power the cooling process. These systems are more expensive to install than regular AC systems, but the long-term savings on electricity bills can make them a good investment for homes in sunny regions.

• Solar-Assisted Air Conditioning: This system uses both solar energy and traditional grid power to cool the home. It works by using solar panels to pre-cool air or power the compressor, reducing overall electricity consumption.
• Standalone Solar Air Conditioners: These are designed to run entirely on solar power, typically combining photovoltaic (PV) systems and a special compressor.

3. Solar-Powered Fans and Ventilators

Using solar-powered fans or ventilators in windows, ceilings, or walls can help circulate air and reduce indoor temperatures. These systems can be very affordable, especially compared to full air conditioning systems, and are ideal for homes in milder climates.

4. Passive Solar Cooling Techniques

In addition to solar-powered equipment, implementing passive cooling techniques can reduce the need for active cooling systems:

• Insulation: Insulating the home, especially the roof, can keep the home cooler by preventing the heat from entering.
• Solar Reflective Paint: Using reflective paint on the roof or exterior walls can reduce the heat absorbed by the house.
• Shading: Installing solar shades, pergolas, or using greenery around the home can help reduce heat absorption.
• Ventilated Roof Spaces: Properly ventilating your roof space can allow heat to escape, reducing the need for air conditioning.

5. Evaporative Coolers (Swamp Coolers) with Solar Power

Evaporative coolers can be paired with solar panels to make them more energy-efficient. These coolers are effective in dry climates as they use the process of evaporation to cool the air. By using solar energy to power the fans and pumps, this system can significantly reduce electricity usage.

Among these options, solar-powered attic fans and solar-powered air conditioning (or solar-assisted cooling systems) are among the most popular and effective low-cost solutions for cooling a home. For a minimal upfront investment, passive solar cooling techniques like insulation and shading are also great ways to complement these systems and reduce overall cooling needs.

I fully agree with Sulaiman Al-Hashmi, and would add to the passive technique that, where the climate is adequate, nighttime large ventilation allows the building mass to cool down, thus keepeing indoors at a reasonable temperature the day after. Adequate climate has a comfortable otdoor average temperature but too hot the day and cooler the night.