【Power saving tips】Cut power bill from building materials. 4 building materials you should know to keep your home cool to reduce air-conditioning usage


Hong Kong is getting hotter and hotter in Summer. Air-conditioner has become a must at home during the hot days. Prolonged use of air conditioners inevitably doubles the electricity bill. Study shows that when the indoor temperature increases by 1°C, the electricity cost of the air conditioner will increase by 6%. How to save electricity while enjoying cool air? HKdecoman is going to teach you how to keep your home cool using different building materials while using less air conditioner.

Energy-saving concept of building materials

The three major paths for the heat of the sun to enter the interior are the roof, the outer wall and the windows. Modern buildings are mostly built with steel, concrete and other materials. In the daytime, the surface of the building is irradiated by the sun, and the walls will start to emit heat in the evening, making the interior area hot.

When the temperature of the wall is higher than the body temperature, it is difficult for human body to dissipate heat indoors thus using the air conditioner to cool the room down. In addition to cooling the body, the wall should be cool to maintain the cooling effect at home. It takes a long time to achieve the effect and consume more electricity.

If you can isolate the hot air from entering the room and block the hot air from entering the room when the floor heat is dissipated, it will become easier to cool down. When the wall temperature is lower than body temperature, the human body will dissipate heat faster, and we will naturally feel cool. This is the ideal and energy-saving method to keep the heat away from the house.

Heat insulation building materials

Thermal insulation glass film

Among the three major heat sources, windows have the greatest impact. Direct sunlight through the window will increase the indoor temperature. However, using curtains will hinder natural lighting. Insulating glass film can improve this situation.

Heat-insulating glass film are called the sunglasses for windows. Insulating glass film are generally used to reflect or block ultraviolet and infrared rays. Some insulating glass films can even achieve 99% infrared blocking rate. After reflecting the infrared rays of heat transfer, the room will reduce the heat absorption rate.

Thermal insulation glass film has other advantages, such as anti-glare, anti-UV, increase privacy, and help prevent fragments from splashing after the glass bursts.


Thermal insulation glass film may affect the penetration of light. Consumers need to weight whether they want to keep the room cool or enjoy the natural sunlight and scenery outside the window. If you want to have both, the price will undoubtedly increase.

Hollow glass window

In addition to sticking heat-insulating glass film on the window, the window itself can also block the entry of heat. Heat conduction, heat convection and radiation are the ways that the sunlight transmit heart to the room.

The hollow glass window is composed of two or more pieces of glass. There is a hollow layer in the middle, which contains inert gas or desiccant. The dry nature of the hollow layer, the characteristics of inert gas and the hollow centre can reduce the speed of heat conduction, so as to achieve the effect of heat insulation. If combined with the coating on the glass layer (such as LOW-E glass), infrared heat transfer can be reduced.

Thermal curtain

In addition to hollow glass window and thermal insulation glass film, you can use thermal curtain with high shading degree and good heat insulation effect to keep your home cool. For curtain fabrics to achieve thermal insulation, the shading of the fabric is very important. The types of thermal curtains can be divided into chemical or physical.

1.Chemical formula

Apply chemicals behind the curtain to block light, such as silver. The coating with better shading rate can block 90% of the light. If the quality is poor, the service life will be shorter, and the coating may fall off in 1-2 years.

2.Physical formula (sandwich curtain)

Use 3 layers of fabric to make a curtain. Use coloured cloth for the upper and lower layers, with a layer of black yarn in between to achieve shading. The shading effect lies in the density of the fabric. The physical shading rate is not as good as the chemical, generally only 70-80% shading rate (it can be improved with quality fabric), but the service life is longer than the chemical formula, about 5-10 years.

Heat reflective paint

One way of heat transfer is to enter the room from the rooftop. In addition to installing heat insulation panels on the roof or planting plants to cool down, there are some heat reflective paints on the market that can achieve waterproof and heat insulation effects, reflecting more than 85% of the sunlight. Experiments have proved that it can effectively reduce the indoor temperature by 5.5 degrees.


The above building materials are mainly used to isolate the heat from sunlight into the house to prevent the indoor temperature to rise easily. If the indoor temperature is comfortable (about 27°C), there is no need to increase the use of air-conditioner. Even if air-conditioner is used, you don’t need to turn the temperature down to keep the room cool to achieve energy-saving effect.


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Author: decoadmin