Passive design is about capturing energy and keeping it in your home.
Passive design is a home construction standard focusing on preserving energy by creating an airtight, well-ventilated home. Initially, passive design focused only on new construction, but retrofits are now becoming smart investments for homeowners who want to save energy while increasing the value of their homes.
Passive House Principles
A passive house must meet certain criteria to obtain this certification. The house must have an energy load of no more than 1.4 kilowatt-hours (kWh) per square foot annually each for heating and cooling. The home’s total energy load cannot exceed 11.1 kWh per square foot. That’s about five times less than the U.S. average. So, an investment in passive home principles can drastically cut your heating, cooling and electricity costs. The main strategies used to achieve the savings include:
- Use More Insulation – Energy is also lost through transfer through solid materials, a process called thermal bridging. Even the most airtight home will not retain all of its energy. In colder climates, stronger R-ratings are needed to contain the heat. Simulation programs are available to help you determine the ideal amount. At the very least, you could use the U.S. Department of Energy’s insulation recommendations based on your home construction, furnace type and ZIP code. You may need to consider insulating other non-conventional areas of thermal bridging such as concrete foundations.
- The Latest Window and Door Technology– To meet the passive house standards, you’ll probably need triple-pane or heat mirror windows. They must have exceptionally low U-factors of 0.05 to 0.15. By comparison, the average dual-paned window offers a high U-factor 0.50. Simulations may be needed to determine the best glass materials and window placement to meet energy goals.
- Make It Airtight – Homes lose energy anywhere there is airflow between the interior and exterior of the house. Anywhere air can escape the home is a problem. You can find out just how much air infiltration trouble your home with a blower door test. Most homes see seven air changes per hour (ACH) when applied with 50 pascals of pressure. A passive home will not exceed 0.6 ACH. Testing lets you find out just how far you need to go to meet the standard.
Of course, an airtight home still needs ventilation. So, high-efficiency heat exchangers and ventilation systems are needed. Heat exchangers transfer the heat in the air exiting your home to the air entering it with efficiency between 75 and 95 percent.
Other Passive Design Benefits
Passive design obviously saves on energy, which saves you money and improves the value of your home. But it also can help prevent common home repair problems caused by excessive moisture. Because airtight homes don’t let humid air infiltrate small spaces in the building, creating condensation and rot, the building degrades less over time.
Let MM Comfort Systems help you incorporate passive design principles into your home.
MM Comfort Systems has the expertise to install and maintain the ventilation and heat recovery equipment needed to meet the passive house standard. Call us at 425.533.9058 or use our online contact form to find out more.
