12 Dec How Heat Transfer Works & How Bulk Insulation Reduces It
To understand why insulation matters, it helps to first understand how heat moves. Heat naturally flows from warmer areas to cooler areas through three main mechanisms: conduction, convection, and radiation.
In buildings, conduction is typically the most dominant form of heat transfer. It is the direct movement of heat through solid materials like roofs, walls, floors, and structural elements. This conductive heat flow happens quickly and causes indoor temperatures to fluctuate based on outdoor conditions.
Bulk insulation, a mass-based insulation such as glass wool comes in various thicknesses and densities and works by slowing down conductive heat transfer. Its fibre matrix traps millions of tiny air pockets, and because air is a poor conductor of heat, these pockets significantly resist heat flow.
By disrupting the path of heat, bulk insulation reduces the rate at which warmth enters or escapes a building. Unlike reflective insulation, which targets radiant heat, bulk insulation primarily resists conduction, making it effective in almost any climate.
By reducing heat transfer, glass wool insulation directly improves a building’s energy efficiency. In hot climates, less heat entering means reduced cooling demand; in cold climates, less heat escaping means lower heating requirements. Regardless of region, slowing heat movement improves comfort and long-term energy savings — which is why insulation remains one of the most cost-effective components in modern building design.
With this foundation in place, the next section explores how insulation performance is measured through R-Value.