How does insulation between inner and outer walls of a home help reduce thermal energy transfer?

explain how insulation between the outer and inner walls of a home helps to reduce thermal energy transfer
Asked Feb 22, 2010
To understand how insulation block's heat from penetrating the walls, we should first understand how thermal energy transfer works. Thermal energy refers to heat and the transfer process may be one of three methods. The first method called conduction allows heat to jump from one particle to another whenever these molecules collided against each other. In this sense, heat is released from the molecule because of friction (work), which is a consequence of force (collision).

Heating up a kettle filled with water best exemplifies this transfer process. First, the heat from the fire travels through the kettle's molecules via conduction and repeats the same process with the water molecules. When the water's boiling, we usually pour hot water into a cup with a tea bag in it. The tea bag doesn't need fire to heat up because the excess heat in the water molecules are carried into the tiny particles that make up tea.

A second method is convection whereby heat flows through a current consisting of matter, such as water or air. As the current of water or air molecules moved from point A to point B, thermal energy (heat) in the molecules was also transported. For instance, the air above a campfire feels hotter than the air far from the blaze. The same principle is at work when you see the air shimmer above an asphalt road during an extremely hot summer day.

A third method is radiation wherein thermal energy (heat) travels through electromagnetic waves. This kind of heat comes from sunlight and consists of alpha, gamma, and UV rays, which can penetrate through solid materials. Aside from the sun, our toasters and old light bulbs also emit infrared rays whose high levels of thermal energy immediately heats up the surrounding air through convection and anything within their vicinity through conduction.

Installing thermal insulation on the inside panels of the interior and exterior walls of a home effectively blocks heat energy that comes from the sun's rays and from the hot air outside. Also, heat that's already inside the house is also prevented from escaping. This keeps the temperature inside your home at a normal level and also saves you money in heaters and radiators.

The insulation materials consist mostly of fiberglass, natural fibers, plastic fibers, rock or slag particles, mineral wool, straw and cellulose, and sometimes foam boards or liquid foam insulation. Other insulation materials were made from recycled plastic and milk bottles as well as concrete slabs fortified with foam beads and air bubbles. These materials have been chosen for insulation because they couldn't conduct thermal energy between them or cause convection of heat through air particles. The kind of insulation applied between the walls depends on whether the building is in the middle of renovations or not.

When you're re-modelling and the exterior walls are already exposed, take the opportunity to insert batts and rolls of insulation materials into the studs, joists and beams. When there are no plans to open up the walls, floors, and foundation, some loose-fill (blown-in) or sprayed foam insulation is injected through a small wall cavity into the spaces between the walls. To increase insulation capacity (measured by R-values), construction workers dry-stacked the insulating concrete blocks inside the double walls. Structural Insulated Panels (SIPs), on one hand, are easily to assemble and help build walls, foundations, floors, and roofs quickly.
Answered Nov 24, 2012
Edited Nov 24, 2012

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