If we want to compare these two terms, we have to first understand their definitions. On the first hand, it is easy define a zero energy building (can be measured in different ways), on the other hand the green building is about efficient use of energy, water and natural materials, and also waste and pollution reduction, which is hard to measure.

Are all net zero energy buildings green buildings? Not really. It is true, that they the achieve the goal of completely or significantly reducing energy use and gas emissions. But zero buildings can not be considered green in other areas, for example using natural materials, waste reduction and others.

However, net zero energy buildings do tend to have a lower ecological impact because they do not require imported energy. Combining these two approaches may be crucial for future sustainability.

What prevents investors and potential owners to construct zero energy buildings? Lets go through the list of major reasons:

1. Lack of information – people dont know about the benefits of zero energy buildings
2. Regulatory issues and lack of legislation – people are not doing more than necessary
3. Lack of expertise – builders do not promote something they do not understand. Only very few designers or builders have the necessary skills or experience to build zero energy buildings.
4. Lack of technology – means technology for new as well as for existing buildings.
5. Cost – major problem. Costs of energy efficiency and renewable technologies are considered to be high and of little value to customers. Zero energy equipment technology price has been falling rapidly per year – there is a risk it will lessen the value of capital invested in a zero energy system.