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passive house design

What is a Passive House?

In its simplest, Passive House (or Passivhaus in Europe) is a housing performance standard that focuses on reducing the need for indoor heating and cooling, while increasing comfort. While solar passive design focuses on its orientation to take advantage of sunlight and wind for heating and cooling, Passive House design has a stronger focus on the building fabric. It was originally conceived in Germany by Dr Wolfgang Feist and Professor Bo Adamson in 1987. Since then, it has become an increasingly common building practice, with strict requirements to receive certification.

Depending on the climate you’re in, these requirements vary. In Perth, we experience both hot and cold conditions. This means our homes have to be uniquely designed to ensure they remain comfortable throughout the year. In order to comply with these requirements, we here at Ecohabit focus on the following elements:

 

airtight design

An important requirement for a Passive House, airtightness means that there are no unnecessary gaps in the building envelope that can lead to air leaking in or out of the building. Extra care is taken during design and construction to ensure all junctions are fully sealed and there are no gaps or cracks around doors or windows.

Having an airtight building envelope is important as it keeps heat from entering or escaping unnecessarily, prevents moisture and humidity from spreading inside, and stops draughts. It also increases energy efficiency, with little to no energy needed to heat and cool the home.

This doesn’t mean you can’t open your windows and doors, it simply means you don’t have to in order to maintain a comfortable temperature.

 

insulation

Insulation plays a vital role in ensuring good Passive House design. It will keep your home warm in winter and cool in summer. To ensure its effectiveness, the Passive House standard requires high levels of insulation with special care to ensure that there are no thermal bridges.

A thermal bridge is caused when a building component has a higher thermal conductivity than the materials around it, creating a path through which heat can travel in or out of the building. Using continuous insulation is the best way to reduce thermal bridges. There are various options available, but we’ll work with you to find the best one for your home.

heat recovery and ventilation systems

The previous elements are all about sealing up a building, but you may be wondering how we ensure there’s still plenty of circulation. We do this with a heat recovery ventilation system. These are systems that create circulation to bring fresh air into your home without losing heat. They do this with two ventilation ducts in the wall that sit next to each other.

One brings cool, fresh air in while the other takes the warm, humid air out. Both streams of air run through a heat exchanger, which allows the warm, outgoing air to give its heat to the cold, incoming air. In summer the system will work in reverse to cool your home.

 

high performance windows

While insulation would be at its most effective with absolutely no windows, that’s not exactly the homeowner dream. So how can you reduce the heat transfer that inevitably occurs as soon as windows are installed? As with ‘Solar Passive Design’, ensuring that windows are double glazed, oriented North and have sufficient shading is important for Passive House design.

On top of this we also recommend using unplasticised polyvinyl chloride (uPVC) for door and window frames. There are many benefits to uPVC, including weather-resistance, durability and recyclability. Most important for Passive House designs, though, uPVC doesn’t conduct heat as much as other alternatives, like aluminium. This means it’s a better insulator and doesn’t cause thermal bridging.

When the weather is nice windows are a great way to bring the outdoors in. But when it’s not so nice, you want them to be designed so the temperature inside stays comfortable. Carefully considering the orientation and building materials of your windows is one of the best ways to save money on electricity bills.

is a passive house for you?

The home design that’s best for you depends on your lifestyle, budget and values.

When deciding between a solar passive design or Passive House design, though, there’s one main question to ask yourself: how often do you like to have your doors and windows open? If you like to them open most of the time, regardless of weather, a solar passive design is probably more appropriate.

If you want a consistent indoor temperature that is minimally affected by the outside weather, a Passive House will be more suitable. If you’re still unsure, we can help you decide at the very beginning of the design process. We’ll sit down with you to learn what you need from a home and discuss the various ways that we can achieve it.

let’s work together

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