Cool relief. That’s the feeling you get entering a full brick house on a hot summer day.
Why is it so? Dense materials such as bricks have what engineers call ‘thermal mass.’ Put simply, heavyweight building materials can absorb and store heat energy, releasing it slowly.
This is a very different quality to insulation (measured by the ‘R-value’), which is a barrier to heat. Unlike insulating materials that have little or no capacity to store heat energy, the mass of brickwork helps stabilise internal temperatures by delaying the passage of heat through the wall.
This delay is called the ‘lag time.’ The higher the level of thermal mass, the longer the lag time. A full brick wall will have a lag time of up to eight hours.
A full brick wall (top) delays the passage of heat through the wall for up to eight hours, well after the peak has passed.
In other words, by the time heat striking the wall penetrates inside, the peak of the day has passed hours earlier, allowing you to ventilate and cool the house naturally.
Tests at The University of Newcastle have shown that a cavity brick wall is more effective than a lightweight wall (with the same R-value) at smoothing temperatures, even on the hottest day.
Although the outside temperature soared to over 45 degrees (light blue line), the temperature inside this full brick test building (red line) was relatively stable and far more comfortable than its neighbouring insulated lightweight building (dark blue line). Chart detail courtesy The University of Newcastle.
What does this mean for you? Air-conditioner use will be reduced (or even eliminated). Your energy bills will drop and the environment will say thank-you. Your full brick home will feel naturally cool and inviting. What a relief!
