The weather can become so hot that you feel the heat in your house. Unfortunately, the roof of your home seems to harbor the heat and return them to you undiminished.

Still, there are some methods through which you can cool the house from the roof. In this article, we will view these methods.

Spraying water on the roof could help cool the house. You can pour water on your roof on hot days, and a significant drop in room temperature will be substantial. One of the strategies to explore is sprinkling your top to keep your house cool.

Key Takeaways:

  • Evaporative Roof Cooling: Spraying water on your roof, known as evaporative roof cooling, can help in reducing the roof’s temperature, and subsequently, the room’s temperature.
  • Mechanism: This method mirrors our skin’s cooling technique. As water evaporates off the warmer roof, it takes away heat, reducing the roof’s temperature.
  • Roof Misting System: A roof misting system, which consists of a sprinkler and a timer, can be particularly effective. The sprinkler scatters water for maximum cooling, and the timer controls its spread.
  • Impact: Spraying water on your roof every 10-15 minutes can reduce your home’s temperature by up to 5 degrees.
  • Considerations: Before spraying water, consider your roofing material and water availability. Avoid this method if you have solar panels, a garden on your roof, or a limited water supply.
  • Alternative Methods: If your house has solar panels or a roof garden, you may not need to spray water as these can naturally keep your home cool.
  • Conclusion: While spraying water on the roof can effectively cool down your house, ensure that it suits your home’s conditions and resources.

Ready for a Roofing Quiz?

Does Spraying Water on Your Roof Cool the House?

Spraying Water on Roof to Cool House

Spraying water on the roof can reduce the roof’s temperature, thereby decreasing your room temperature. Spraying water on a roof is known as evaporative roof cool. 

This system seeks to keep your house cool by reducing the available heat in the radiation process. On a sunny day, solar energy radiates from the sun to the roof, and the sun absorbs heat.

When the roof absorbs heat radiated by the sun, the room receives most heat through conduction and radiation. This heat transfer alters the room temperature.

During the day, the roof and walls trap the heat and emit it at night. Spraying the top of your home cools down the roof, preventing the roof from trapping the heat. 

Does Spraying Water on Roof Lower Room Temperature?

Using any available technique, spraying water on the roof lowers the room temperature. Then, when running through the roof, the water cools it via evaporation.

The working mechanism of this cooling technique is almost the same as that of your skin.

As water with a slightly cooler temperature runs through a roof with a higher temperature, the heat evaporates the water as it runs through it.

The heat given off constantly increases, reducing the amount of heat radiating into the room. One of the most effective means of cooling your room by spraying the roof is via the roof misting system. 

This system involves a sprinkler and a timer. The sprinkler splits the water into droplets for higher impact, and the timer controls the periods with which the water spreads across the roof.

Water in this form covers more roof areas and cools it faster. Water in this form also lasts longer on the roof, making them more excellent.

In addition, mists often rise above the roof, thereby forming an envelope of protection above the roof. It includes an extra layer against the radiating sun rays. 

If you do not have a roof misting system, you could have water run through your roof directly. This pattern of spraying water on your roof also keeps your house cool under the scorching sun.

In addition, the water cools your roof down through the process of evaporation. This process occurs due to the temperature difference between the water and the hot roof. 

On a Hot Sunny Day, Why Do People Sprinkle Water on the Roof?

You can get your house to cool down by sprinkling water on your roof. Many people sprinkle water on their roofs on a hot sunny day to cool them down.

Once the top cools down, the temperature of the house also drops. So spraying your roof on a hot sunny day can reduce the temperature of your living room.

This method is a cheap and energy-saving mechanism to cool your house down.

The temperature in the room is affected by a lot of factors. The type of roof plays an essential role in the room’s temperature.

The top may have supplied the most heat when the room gets hot. Spraying the ceiling can cool the house.

Though the type of roof matters, most roofing materials used in modern-day homes are known to trap heat, this heat is circulated evenly around the house’s interiors.

Therefore, other methods applied in cooling the house may not be effective because of the constant supply of heat from the roofing materials.

Therefore, using water on your home’s roof may just be what you need to cool down your house more effectively.

Why Should Someone Spray Water on Their Roof to Cool their House on a Hot Sunny Day?

You can get your house cooled down by spraying water on your roof. You should have a water sprinkler on your top on those hot sunny days if:

#1. Your Roofing Material Absorbs Heat

Most roofing materials absorb heat. But, unfortunately, only a few of them out there keep the heat away. Once your roof is the type that traps heat, then you should spray water on it.

#2. You Have Sufficient Water

You need a great deal of water to pull this off. However, if water is in an abundant supply, then you can go on to spray the roof of your house to keep it cool.

Why Shouldn’t Someone Spray Water on Their Roof to Cool Their House on a Hot Sunny Day?

Despite your house heating up on that hot sunny day, you should not sprinkle water on your roof if:

#1. You Have Solar Panels Installed

With solar panels on your roof, it becomes unnecessary to spray water on your top, and this is because the solar panel roof absorbs all the light rays causing the heat.

As a result, the room may not be hot even though you can use the electric energy generated from solar energy to power other forms of cooling systems.

#2. You Have a Garden on your Roof

Not all roof forms trap heat. For example, you sure do not need a water sprinkler when you have a garden planted on your roof.

Even if you sprinkle water, it will not affect your house. Instead, the garden plants absorb all the sun’s heat and channel it into growing green.

#3. You Have Little Supply of Water

To keep your room cool by sprinkling water on the roof demands a lot of water. If you do not have an adequate water supply, you must explore other means.

You will need a good water supply once every 10-15 minutes to cool down your house effectively.

Will Wetting Roof Cool House?

Of course, wetting your house’s roof will cool down your house’s temperature. You are sprinkling your roof with water once every 10-15 min reduces your home’s temperature by 5 degrees.

The evaporation of the heat causes this drop in temperature. If you wish to conserve water, you could do this only at night or use the automated water sprayer.


You can lower the temperature of your house by spraying water on your roof. The water sprinkled on your top reduces the temperature of your home through evaporation.

The temperature of your house goes as low as 5 degrees when sprayed for about 10-15 min. You don’t need to spread your roof if you have solar panels and a garden on your rooftop.

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