Bricks are an essential part of energy efficient design
Bricks build in thermal mass. This mass is a key part of passive design, a proven method of keeping your home at a comfortable temperature all year round and reducing the need for cooling devices. Thus, lowering electricity loads and your costs.
Thermal mass acts as a "termal battery". In a hot day, thermal mass absorbs, keeping the house comfortable.
Bricks are energy efficient in manufacture
Using the measurement known as Embodied Energy (the energy consumed in the manufacture of various building materials) it has concluded that clay bricks have less Embodied Energy than aluminium, steel, glass, or timber.
More importantly, over the lifetime of a home the energy consumed in the manufacture of the materials accounts for only 5%. The other 95% is the ongoing running of the home, of which a significant proportion is for cooling. The less of this required, the less direct impact there is on the environment.
Bricks are energy efficient in application
Brickwork can be very energy efficient, but designing a house to be cool must take into account more than just the walling material. There are four key factors:
- Orientation - Placement of the house in relation to the sun.
- Insulation - A wall's ability to isolate temperature.
- Ventilation - Air flow through the house.
- Mass - Heavy weight wall materials slow the passage of heat through a wall, a process called 'thermal lag'. And the easiest way to get this heavy mass into walls is brickwork. The heavier the brick, the higher its thermal value.
The R-Value - is it the right measure?
Another issue highlighted by research is a deficiency in using the Thermal Resistance Value, or R-value of the wall, to measure the thermal efficiency of a building.
The thermal mass of clay bricks provides a time delay for heat transfer through the walls known as thermal lag.
It can be seen that high density walling materials do not fair well when assessed purely on the criteria of "R-value", however, when assessed on Thermal Capacitance clay bricks outperform their lightweight counterparts. It is for this reason that clay bricks are thermally more effective than the "R" value alone would indicate.