The Role of Insulation in Passive House Design

Have you ever wondered why some houses easily maintain a comfortable temperature without a lot of heating or air conditioning? The secret to this solution lies in the design of the house itself, usually known as "passive design".

There are various techniques to promote natural warmth in the winter and cooling in the summer. By implementing a well-planned passive design, you can significantly lower your energy bills, and reduce the impact on the environment which occurs when using artificial heating and cooling systems.

What Is Passive House Design?

A passive house is a standard of construction that focuses on creating buildings with very low energy needs for heating and cooling. The core principle of a passive house is to minimize heat loss and maximize its gain to become an energy-efficient and comfortable living space.

To achieve this, insulation is very important, as well as creating airtightness, having extremely good windows, and similar. When adhering to the passive design standards, you could enjoy great energy savings and a cozy sustainable environment.

The Key Points of Passive Design

There are a few main principles that support the whole concept of passive design:

• Orientation

The placement of your house on the lot and its orientation play a big role in reaching an efficient passive design house. By carefully considering these factors, you can make huge improvements. For example, in regions with warm climates (in the northern hemisphere), it’s better to minimize direct exposure to the sunlight, meaning longer walls should face north to reduce the heat inside.

On the other hand, in cooler states walls facing south can get the most out of sunlight and provide warmth during the whole year, especially in winter months. By planning and aligning your home with its surroundings, you can maximize energy efficiency and have a comfortable temperature in your home all through the year.

• Thermal mass

When choosing a building material for your house, consider its heat distribution abilities. Some materials, like brick and masonry, are known for exceptional heat absorption capabilities. They can absorb the heat and gradually distribute it throughout your home.

If managed and controlled properly, the amount of sunlight or heat coming from other sources will get absorbed by brick walls, concrete floors, and other dense materials, so you’ll be in control of the heat in your living space.

• Insulation

Obviously, you can’t have an energy-efficient passive house without the right insulation. You must properly insulate walls, ceilings, and floors to make sure the heat is distributed where it should be and where it’s needed. By properly insulating your house, you can optimize energy savings, maintain comfortable temperatures, and manage the heat flow within your home.

• Windows

The type of windows you choose also counts. To control the heat transfer through them, you should consider several factors. Think about the size of the windows, the height, use of advanced glazings and films on the glass, shading, etc. With that in mind, you can regulate the heat flow easily, enhance or reduce it depending on the season, and live in an energy-efficient environment.

• Shading

For a successful passive design, you have to consider shading. Installing well-designed eaves, pergolas, and awning can help a lot in achieving this, however, planting trees outside your house is an excellent natural solution that many tend to forget. Trees will offer you shade in the summer, and lose their leaves to provide more sunlight in the winter.

Why Do People Build Passive Houses?

Passive houses are becoming more and more popular among young people and families, not only because of their low environmental impact, but also of the exceptional comfort they provide, and, of course, the long-term savings. Passive houses are usually ranked very high on the real estate market due to their reduced costs and energy efficiency.

Passive design standards can also expand beyond residential properties and be used for commercial buildings like schools, hospitals, and offices, as they represent a greener and more sustainable construction practice.

What Is the Best Insulation for Passive Houses?

The best insulation for a passive house would be one that has excellent thermal resistance, so-called R-value, and air tightness. Some of the most commonly used materials are:

• Mineral Wool, rock wool, or fiberglass are very common insulation materials that provide very good thermal insulation. Still, even though these materials are affordable, their quality can decrease with time.
• Expanded Polystyrene and Extruded Polystyrene provide high R-value and moisture protection while being very durable. EPS is mostly used for roofs, floors, and walls, while the XPS is made for foundations, slabs, and below-grade applications.
• Cellulose is a material made of recycled paper and treated to be insect and fire-resistant. It offers a good R-value and is usually blown in or sprayed onto the walls and its cavities.
• Spray foam is probably even better for passive houses than materials like fiberglass or cellulose, because of its high-performance insulation properties, such as great R-value and airtightness, water resistance, durability, and adaptability. Spray foam can be applied to almost any surface, and fills up any hard-to-reach activity. However, you may need professional help when applying it to your house.
• Prodex Total is an insulation material made of reflective foil covering a layer of closed-cell foam on both sides. It comes in light rolls that you can also handle and apply by yourself and is a perfect solution for insulating any surface. Prodex Total has a very high R-value, completely blocks radiant heat transfer, and is moisture, rodent, and mold resistant. This material is pretty easy to measure, cut, and install on ceilings, walls, and floors of all types and surfaces.

Where Is Insulation Needed?

For efficient thermal performance, it’s important to insulate all walls, ceilings, and floors in your house. The insulation on the walls and ceilings should be a strong combination of reflective and bulk insulation, which can retain the heat inside the house, and the floors could be approached differently, depending on the type of subfloor.

Here are the areas where insulation is usually required:

• Walls: Insulation is typically needed on exterior walls to minimize the heat getting in or out of your house.
• Roofs and ceilings: Insulation here is needed to prevent heat loss, as the warm air usually rises and escapes through the roofs. With the roof/ceiling insulation, you can also prevent the heat of the summer sun, warming up your home beyond the desired temperature.
• Floors: Insulation is important in floors, too. If your living rooms and bedrooms are placed above the unheated space like a garage or a basement, you would especially want to insulate the floors and prevent heat loss.
• Doors and windows: Even though that isn’t technically an insulation, well-sealed doors and windows are essential for reducing heat loss, or gain, and the overall energy efficiency in passive house design.

Insulation Works Only Combined With Ventilation

In passive house design, proper ventilation is probably as important as the insulation. If you manage to achieve optimal airtightness in your house, air quality can be at stake if you don’t have proper ventilation.

To maintain a healthy environment for your family to live in, consider installing mechanical insulation systems with heat recovery (MVHR). This is a balanced ventilation system that allows constant but controlled airflow while able to recover the heat from the outgoing air to pre-warm the incoming air.

Of course, the MVHR system must be measured and set up according to the specific needs of the house to make sure it works properly and provide the right ventilation and heat recovery.

Passive House Benefits

If built according to the passive house standards your house will bring you amazing benefits starting from energy efficiency, and your everyday comfort, to the fact that you own a property of very good value.

Your house will consume significantly less energy on heating and cooling, allowing you to save much more money than you could ever do in a conventional building, and minimize your carbon footprint.

Thanks to such design and insulation, the temperature in your house will be consistently balanced and comfortable, while a mechanical ventilation system, along with good insulation will assure you fresh air while the stale air goes out.

Finally, passive house certification increases its value, which makes it also a very smart investment for homeowners. Such design shows outstanding energy efficiency, sustainability, and durability, which is certainly attractive to any environmentally conscious buyer.

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