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Passivhaus Q&A Series: What’s the difference between a new energy efficient home and Passivhaus?

This post is part of our series that shares questions we regularly receive about Passivhaus and low energy construction. We will be posting a new one every week. Explore our Blog to learn all about why designing buildings to low energy standards like Passivhaus delivers a lot more than just energy savings.


Energy efficient vs Passivhaus. What's the difference?
Energy efficient vs Passivhaus. What's the difference?

As sustainability becomes increasingly paramount in home construction, terms like "energy-efficient homes" and "Passivhaus" often pop up. While both prioritise energy efficiency, they aren't quite the same. Let's uncover the nuances between these two construction methodologies.


Defining energy efficient homes:

An energy-efficient home, in its broadest sense, is designed to reduce energy consumption, thereby minimising greenhouse gas emissions and utility bills. These homes incorporate various techniques and technologies to achieve this:

  1. Insulation: Proper insulation in walls, roofs, and floors reduces heat transfer, maintaining a comfortable indoor temperature.

  2. Efficient Appliances: 'A-rated' appliances consume less energy while providing the same functionality as their conventional counterparts.

  3. Advanced Windows: Double or triple-glazed windows, sometimes filled with inert gases, minimise heat loss.

  4. Renewable Energy: Many energy-efficient homes use solar panels, wind turbines, or other renewable sources to generate electricity.

The specifics can vary widely, depending on local regulations and climate. However, the unifying factor is a reduction in energy use compared to conventional homes.


Unpacking the Passivhaus Standard:

Passivhaus, originating from Germany, represents a stringent, holistic approach to energy-efficient construction. It's not just about incorporating a few energy-saving techniques but rather a comprehensive method that ensures minimal energy usage. Key features include:

  1. Ultra-insulation: Passivhaus buildings typically have much thicker insulation than even most energy-efficient homes.

  2. Airtightness: One of the hallmarks of the Passivhaus standard is its airtight construction, preventing unwanted drafts and energy loss.

  3. Thermal Bridge-Free Design: All junctions and connections in the building are designed to prevent heat transfer.

  4. Mechanical Ventilation with Heat Recovery (MVHR): This system ensures fresh air intake while retaining most of the internal temperature by transferring heat from the outgoing stale air to the incoming fresh air.

  5. Passive Solar Gain: By strategically placing windows and using advanced glazing, a Passivhaus utilises the sun's energy to aid in heating the home.

For a building to be termed a Passivhaus, it must meet specific criteria set by the Passive House Institute or similar accrediting bodies.


The differences:

  1. Rigidity vs. Flexibility: Passivhaus has a rigid set of criteria that must be met for certification. In contrast, an energy-efficient home can be a blend of various techniques and technologies that might not adhere to a specific standard.

  2. Performance Assurance: With its stringent criteria, a Passivhaus guarantees a certain level of energy performance. An energy-efficient home might not have such guaranteed performance metrics.

  3. Construction Techniques: The construction techniques in a Passivhaus are specific, ensuring airtightness, absence of thermal bridges, and optimal passive solar gain. An energy-efficient home might not employ all these methods, although it will use some.

Conclusion:

While both new build energy-efficient homes and Passivhaus constructions aim to reduce energy consumption, the Passivhaus standard takes a more rigorous, all-encompassing approach. Energy-efficient homes incorporate methods and technologies to save energy, but without the strict criteria and guaranteed performance of a Passivhaus. For those seeking the pinnacle of energy-efficient construction, the Passivhaus standard is the gold standard. However, any step towards more energy-efficient living is a step in the right direction.

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