What Is a “Passive House” and Why Should you Care?
You may be losing a lot of money if you don’t understand what passive house design means. We tend to use the words passive house just as much as the word “green” when it comes to home design. Here is what you need to know about what “passive house” means.
About Passive House
To understand the term “passive house,” it’s important to look at an example. Say someone says, “this house was designed using passive solar principles.” What this means is that the house is designed in such a way that it’s going to get heat from the natural daylight. The energy consumption of this house is reduced as it’s taking better advantage of the natural sunlight. The architect used “passive house principles” and built the structure to a set of building standards that promote lower energy consumption. Since this house gets additional sunlight, it’s not going to require as much heating, and its impact on the environment is reduced. The term comes from “Passivhaus,” in Germany.
Let’s look at another example. Say a house is a “certified passive house.” This means that the house is built to the standard for a passive house and that it is also certified in that regard. These certifications are managed throughout the world. Passivhaus in Germany is the one that is highly regarded on a global scale. Other areas such as the Mediterranean are working on their own standards for their individual climate. In the USA, the largest certifier is the Passive House Institute which looks at the regional climates in the USA.
Passive House Standards
A passive house that takes advantage of solar heat coming in through a window is saving energy. A house can be designed so that during each season, it’s providing the maximum amount of heat for a home naturally without wasting a lot of extra energy. The home provides a great living environment and is better for the environment due to its design. These homes built to the Passive House Standard remain comfortable in all seasons without an active cooling or heating system present.
Countries and the local area where the home resides will have different standards. The project needs to meet the annual energy limits to be considered as a Passive House. In Europe, this is still 15 kilowatt-hours per square meter each year. The USA had made changes to this standard to address different climates in the country. These homes save around 60-70% or more in energy savings when you compare them to a regular conventional structure. A home doesn’t need to use eco-friendly materials to be certified although many do. Standards are based upon energy performance.
How Can a Home be Passive?
A Passive Home is a bit different. They tend to look like a box and have a compact shape to them. Covered spaces, as well as unconditioned outdoor rooms, can be added for the façade to add some visual intrigue. The compact core of the structure is the basis for the design and improves efficiency.
If the home features a passive solar design, then it’s going to take as much heat a sit can form the sun as the home is oriented towards the path of the sun. The low angle of the winter sun can penetrate the home as much as possible. The residents in the home also add to the heat. Daily activates like computer use, appliance use, cleaning, cooking and so on help to heat the home.
Air is kept fresh with mechanical ventilation. The incoming air is heated with the exhaust air. To prevent mold and to maintain a healthy level of moisture, the home has dehumidifiers
In the summer, for example, a home may have shading devices for the higher sun angle. The sun may not be able even to reach the windows. The walls, floors, and windows get less sunlight so the home stays cool. The home may be insulated and sealed so the heat can’t pass through it.
In a passive home, the windows are critical. You need to have high-quality windows, and this is one of the largest expenses. All the openings have to be insulated in the home. The windows contribute a large portion of the overall energy savings. You can change the insulation a great deal, but if you have poor windows, then you’re going to lose a lot of heat.
Other Things to Consider
You need to look at all the ways that air may escape in the structure. You must plug the places where air may leak, such as the windows. Using the Passive House standard, you can check for air leaks using the Blower Door Test. The whole house is closed and then air is pumped inside. A gauge is used to measure this air. The airflow rate is measured relative to the house volume.
Do You Need the Passive House Standard?
Some people believe that you don’t need to use the Passive House Standard and feel that certification is a bit redundant. Others feel that it adds transparency, especially if you’re going to sell the home. Some feel that the certification adds resale value to the home. Others feel it’s not necessary if they have no intention of selling.
Know you know more about what Passive House is. The Passive House standard is used to determine whether a home meets these criteria. You will know if a home is considered a Passive House if it’s certified.