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Why do we need to insulate our buildings?

 

Insulating your house helps to maintain a comfortable living environment by maintaining inside temperatures and reducing energy costs.

The main purpose of insulation is to create a barrier around the building, that is, over the roof, on the wall, and beneath the floor, which reduces the amount of heat entering the home on a warm day, and reducing the amount of heat loss on a cold day.

The below diagram illustrates the different ways how heat/cooled air is lost the normal house.

House_loses

 

Since the majority if heat is lost or gained through the roof and the exposed walls, these areas are the most fundamental places to insulate in order to create a comfortable and energy efficient home.

 

How does insulation work?

On a hot day, like most typical Maltese days during the period from May till September, a concrete roof and walls exposed to the sun without insulation will start to absorb heat from outside the building. The roof will become hotter and hotter, and will start to emit this heat in the building, which will result hotter environment within the building.

Due to the concrete and bricks' heat capacity, the roof and walls remain warm during the night, and the inside of the building becomes uncomfortably hot during summers.

The opposite happens during winter, in which the heat from the house is absorbed by the roof and walls, and emitted outside. During night-time the inside temperature can easily match the chilling outside temperature.

Heat always travels from the hotter area towards the colder area. The only way to stop this process is through good insulation. In a house with insulation, heat flow through the ceiling and walls is vastly limited, depending on the thermal conductivity of the material installed.

Good insulation will prevent heat from travelling through the roof and walls, thus the building temperature can be kept comfortable with much less heating and cooling energy. Therefore the inside of the building remains relatively cooler than the hotter outside environment,and on a cold night or during winter, the majority of heat that is inside the house will remain trapped by the insulation barrier, thus keeping the buildingwarm.

Insulating your home is like wearing a jacket in winter, and like staying under and sun umbrella in summer.

 

What about Heaters/Air Conditioners?

During tempurature extremes in homes without insulation, heaters and air conditioners are inefficient. This is because the rapid heat exchange through the ceiling an walls causes most of the heat to be lost on a cold day, or on a hot day too much heat to re-enter the home. Because of this constant heat loss/gain, the devices are required to run constantly and at close to maximum power just to maintain a comfortable temperature.

 

A good way to picture this is by imagining a fridge with the door open. The cool air inside will not stay cool for long and the compressor will have to run constantly just to try and keep the temperature down. This is similar to a house without insulation. When the door on the fridge is closed, however, a barrier is created which stops the cool air from escaping and the heat from entering. This is similar to how insulation works.

 

In a house that is insulated, heaters do not have to run as hot or as long to bring the tempurature up to a comfortable level, as more heat is retained by the insulation. The same applies for air conditioning on hot days - it is not required to run as long as the cooler tempurature inside will not be invaded by the majority of the heat from the ceiling.

 

How effective is roof and wall insulation?

A house with insulation can reduce heating and air conditioning costs by up to 40%. This translates to massive savings on energy bills and a lot less pollution due to less energy usage. The money saved from reduced energy consumption greatly outweighs the cost of the insulation which, in the end, essentially pays for itself.

 

The effectiveness of insulation as a heat barrier is deteremined by many factors, however it is largely and most importantly determined by its thermal conductivity. This value denotes the resistance the material has against heat transfer across the material.

This is the common value that industry uses as a comparison between products, however it is not the only factor on which a decision should be made (other important factors affecting one's decision should be cost, safety and feasibility of the product).

 

Insulation is only one part of an energy-efficient home. Other areas of heat loss/gain are windows/doors, walls, air-gaps and even the floor. While the ceiling contributes the most heat lost and gained in a home, the other areas should also be considered. Having windows tinted and covering with thick curtains can also help, as can opening and closing doors and windows at appropriate times of the day.

Other underestimate heat generating devices are lamps, especially halogen lamps, which create lots of heat. Now a day the cost of green substitutes such as LED lights is low. These apart from generating nearly no heat, they consume a fraction of the electricity of a traditional bulb. (We also carry a range of both domestic, commercial and steet LED lighting products)