Heat storage capacity

Bricks, stone and concrete are effective heat storing materials. They need to interact with the house's internal environment. For example, a concrete slab will absorb and store the sun's heat during the day, if it's covered with slate, hard vinyl or ceramic tiles. When the sun sets, the slab is still warm, so your house keeps a pleasantly even temperature around the clock. If the concrete slab is covered with carpet or cork, the heat coming in through the windows cannot be stored in the slab, because cork and carpet are thermal insulators - these floor-coverings will prevent heat flowing into and out of the slab. Slate or tiles (ceramic or hard vinyl) are good choices in rooms where the sun comes in.

Internal brick walls will also act as heat stores. Brick veneer walls do not store heat inside the house, as the bricks are on the external leaf of the walls, and do not interact with the internal environment. Reverse brick veneer, with the bricks on the inside and a light insulated shell (eg fibro-cement sheeting) on the outside, is a much better option.

In cooler climates, larger north-facing windows are needed. As the area of north-facing glazing increases, the amount of heat-storing material in the house needs to increase, too. A house with big north windows and light construction will overheat on winter days, because there is little internal heat-storing material to absorb the incoming heat.

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