what-is-a-passive-house

What is a Passive House?

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Passive houses are becoming a popular choice for people looking to reduce their energy bills and live in eco-friendly homes. These houses are not a specific style but a standard for building energy-efficient homes that stay warm in winter and cool in summer with minimal energy use.

Originating in Germany in the late 1980s, passive houses have spread across Europe and are gaining interest in Ireland. From airtight construction to advanced ventilation systems, passive houses are designed to use less energy while providing a comfortable and sustainable living space. 

In this blog, we’ll explore what is a passive house, how they work, the standards they need to meet, and their costs in Ireland.

What is a Passive House?

A passive house, also known as a Passivhaus (from German), is not a specific type of home but rather a high standard for energy efficiency. Homes built to meet passive house standards share these key characteristics:

  • Buildings made with materials that drastically reduce energy use.
  • Minimal energy is needed to stay warm in winter.
  • Minimal energy is required to stay cool in summer.

Instead of being a design style, the passive house standard works as part of the architectural planning and building process. While often used for new construction, older homes can also be adapted to meet these standards with significant renovations.

The concept originated in 1988 through collaboration between Bo Adamson of Sweden’s Lund University and Wolfgang Feist from Germany’s Institute for Housing and the Environment. The first homes designed to meet passive house standards were built in Germany in 1990. By 2010, over 25,000 passive houses were built worldwide.

In Ireland, the first passive house, “Out of the Blue,” was constructed in 2005 by Tomás O’Leary. According to the Passive House Association, around 45 passive houses have been officially registered in Ireland, showing a growing but limited adoption.

How Do Passive Houses Work?

Passive houses focus on reducing energy use and making homes more efficient. Here’s how they achieve this:

Airtight Construction

Passive houses are carefully sealed to stop air from escaping, making it easier to maintain comfortable indoor temperatures. This is achieved using advanced air barriers and heat recovery systems.

Natural and Energy-Saving Lighting

These homes are designed to allow as much sunlight as possible, reducing the need for artificial lighting. Where needed, energy-efficient options like LED lights are used, often powered by solar panels.

Efficient Heating

Solar energy is maximised to heat the home, and additional warmth comes from household appliances and the people living inside.

On colder days, an extra heating system connected to the ventilation system may be used, powered by renewable energy like solar thermal panels.

Ventilation Systems

Passive houses exchange indoor air with outdoor air while maintaining a comfortable temperature.

During winter, heat recovery systems warm incoming air. Some homes also use pipes buried underground to naturally warm or cool the air before it enters the house.

High-Performance Windows

Instead of standard double-glazed windows, passive houses use triple-glazed windows with special coatings to keep heat in during winter and out during summer.

What Are the Standards for Passive Houses?

To qualify as a passive house, a building must meet strict requirements, including:

  1. Heating and Cooling Limits
    The energy used for heating and cooling must not exceed 15 kWh per square meter annually. For example, a 200 m² home should use no more than 3,000 kWh a year, which is much lower than the Irish average of 11,000 kWh for gas heating.
  2. Energy Use Limits
    Total energy consumption, including electricity and heating, must stay below 60 kWh per square meter per year. For a semi-detached 200m2 house, the average energy consumption is approximately 11,000 kWh of gas and 4,000 kWh of electricity per year, totalling 15,000 kWh.
    In contrast, a passive house is designed to be highly energy-efficient, with a maximum energy consumption of 12,000 kWh per year.
  3. Airtightness Standards
    The rate of air escaping the building must not exceed 0.6 times the volume of the house per hour. A blower door test is used to measure if the house meets this requirement.

Homes meeting these standards often don’t need traditional heating systems, relying instead on advanced ventilation and heat recovery systems.

How Are Passive Houses Certified?

The EU introduced guidelines requiring all new homes to meet nearly zero energy standards or passive house standards. While the original 2020 deadline was ambitious, it highlighted the importance of energy-efficient building practices.

In Ireland, there isn’t an official body for passive house certification, but the Passive House Association of Ireland provides training for builders and architects. The Royal Institute of the Architects of Ireland also offers a European Passive House Designer course accredited by the Passivhaus Institut.

When hiring professionals to build or adapt a passive house, ask about their experience with these standards and any relevant training they’ve completed.

How Much Do Passive Houses Cost in Ireland?

Passive houses in Ireland are available in various designs and price ranges. Here are some examples with approximate costs:

  • Ecohouse: Offers six pre-designed homes, from small to large options.
    • Self-build option: Costs approximately €750 per square meter (you manage the construction).
    • Full-build option: Starts at €2,000 per square meter (handled entirely by professionals).
  • Viking House: specialises in timber-framed houses and solar panel systems. Pricing varies based on the size and features. Contact Viking House for specific estimates.
  • Scandinavian Homes: Based in Galway, this company provides prefab low-energy timber-frame houses:
    • Affordable option: A 78 m² passive house starts at approximately €105,000.
    • Larger designs: are also available, with prices depending on size and customisations.

Conclusion!

Passive houses offer a sustainable and energy-efficient way to live, reducing energy bills while ensuring year-round comfort.

With features like airtight construction, advanced ventilation, and energy-saving designs, these homes are ideal for those looking to reduce their environmental impact. Whether you’re building a new home or exploring options to meet passive house standards, professional guidance is essential. 

At BuildTech Homes, we specialise in creating high-quality, energy-efficient homes designed to meet your needs. Contact us today to discuss your passive house goals and create an eco-friendly and comfortable living space with BuildTech Homes!

FAQ’s 

1. What is a passive house?

A passive house is designed to significantly reduce energy use while providing a comfortable living environment. It achieves this through airtight construction, efficient ventilation, and energy-saving features that maintain warmth in winter and coolness in summer with minimal energy consumption.

2. Can older homes be adapted to meet passive house standards?

Yes, while passive house standards are most often applied to new builds, older homes can also be retrofitted. This process involves significant renovations, such as improving airtightness, upgrading windows, and adding advanced ventilation systems.

3. How do passive houses maintain comfortable temperatures?

Passive houses use solar energy, heat from appliances, and body heat to maintain warmth. They also rely on advanced ventilation systems with heat recovery to manage air exchange and maintain comfortable indoor temperatures throughout the year.

4. What are the main requirements for a passive house?

Passive houses must meet strict standards, including:

  • Annual heating and cooling demand is under 15 kWh per square meter.
  • Total energy use below 60 kWh per square meter per year.
  • Airtightness to prevent air leakage, tested with a blower door.

5. Are passive houses expensive to build in Ireland?

The cost of a passive house in Ireland varies by design and construction method. A self-build can cost around €750 per square meter, while a fully built home starts at €2,000 per square meter. Prefabricated options, such as those from Scandinavian Homes, start at approximately €105,000 for a 78m² home.

6. Is there an official certification for passive houses in Ireland?

Ireland does not have an official passive house certification body, but the Passive House Association of Ireland provides training and guidance. It’s important to work with architects and builders experienced in passive house standards to ensure compliance with the requirements.

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