**3. Why net-zero energy buildings?**

In the last decade, energy costs have been rising, fuels are running out, and there have been global warming issues. For example, the United Kingdom has only 2 years of gas reserve, which has been put on hold of usage, and is currently buying from other countries such as Qatar and the United States. In addition to that, there have been many other issues such as health, well-being, and pollution which could be reduced if emissions are reduced as a result of better energy consumption plan.

Power stations convert only 30–35% of the input energy into electricity. The rest is rejected as waste heat. The United Kingdom alone wastes £20 billion each year by heat rejection from power plants which if used appropriately could heat Britain.

Earth's source of fossil fuel is vanishing at a much rapid pace during the last 200 years causing high damage rates to climate change. New reserves of fossil fuels are becoming harder to find. Those that are discovered are significantly smaller than the ones that have been found in the past. Oil reserve is expected to vanish between 2050 and 2060 and so does that for gas. Coal will last longer and is expected to last till 2100 [13].

Other aspects of increased emissions and increased rate of energy consumption are global warming and significant increase rate of ice melting and glaciers. A prominent red flag out of these aspects is that nine of the ten warmest years since 1880 have been in the last decade [14]. For global warming concern, Miami has seen a temperature rise of 3°C.

A building that is designed to be more sustainable has the potential to reduce the human impact on the environment. This effect is shown in **Figure 2**.

**Figure 2.** *Effect of sustainable buildings on the environment, social life, and economic development.*
