Energy Smart Homes

The decision on a construction standard is usually made based on three aspects:

1) Comfort and well-being

2) Cost

3) Ecology

All three can have differing opinions, so the choice depends greatly on individual beliefs and living preferences. Unfortunately, discussions about building standards can be very emotional and lack objectivity. The best approach is to be well-informed. I want to contribute to this.

A passive house offers advantages in all areas. I will outline its most essential characteristics and the benefits of this design.

I will also briefly describe solar houses and discuss zero-emission standards.

Passive House

The term "passive house" has become a standard for energy-efficient homes. The concept revolves around constructing a house that does not require a traditional heating system. Instead, the house should maximize natural heat and sunlight for warmth. This necessitates thorough insulation and airtight construction. In terms of clothing, this is similar to wearing a warm wool sweater or fleece jacket with a windproof layer.

Fresh air is essential in the house, and the heat from the outgoing air is captured and redistributed throughout the living spaces (heat recovery). This system can also be used to warm incoming fresh air when needed. This approach allows for a heat output of about 10W/m, corresponding to an average heating characteristic value of 15 kWh/(m² a) in central Europe. This translates to approximately 1.5 litres of heating oil per square meter yearly, which is only about 10% of Germany's average heating characteristic value.

This design consideration is crucial as it ensures that the house doesn't overheat in the summer, preventing unnecessary energy consumption for cooling.

Building envelope

When designing a building envelope, it is important to consider utilizing incident solar radiation and minimizing heat loss. It is essential to pay attention to details such as preventing thermal bridges and leaks. Good planning and advice are crucial, especially for complex structures. Windows are particularly important, as even minor errors in installation can have a significant impact. It's also important to carefully evaluate the development and material of the windows, as they constitute a significant cost factor in a passive house. The design should account for temperature differences between the interior and exterior to ensure air tightness and heat insulation.

Proper insulation and high-quality windows are essential to minimize heat loss. The thermal coefficient U-value for walls should be less than 0.15 W/m²K and less than 0.8 W/m²K for windows. Insulation and avoiding thermal bridges are key to saving energy. Different types of walls, such as massive walls with insulation and wood stud walls with insulated space, have different characteristics and cost implications.

In addition to insulation, it's essential to ensure that the house is built as airtight as possible to prevent uncontrolled air leakage, which can lead to condensation and structural damage. Careful planning for the installation of windows and the penetration of the envelope for plumbing or electrical installation is necessary to maintain the integrity of the building envelope.