By definition, a passive constructed house means that the design takes advantage of the area climate to maintain an ideal temperature range inside the home. Therefore, when a contractor or engineer designs a passive house, some defined principles included are the structure is airtight, and thoroughly insulated to reduce heating and cooling loads to provide maximum energy efficiency without minimizing the occupant’s comfort.
There are some key elements to understand about a passive house construction.
With the advancement of technology and the realization of the importance of becoming more energy efficient, sustainable designs for residential uses are becoming more popular than ever.
A passive design doesn’t need exterior solar panels to convert the sun’s energy to power because it uses building materials that actually capture the sun’s radiant heat and transfers the heat directly into the airtight building. Plus, by using a no-gap continuous insulation plan throughout the whole house and energy-efficient windows along with controlled ventilation, passive constructed homes have the ability to heat and cool the house by only using 15%-25% of the energy compared to traditional methods, while still maintaining comfortable indoor temperatures for your family.
Since a passive design depends on natural elements to amplify the energy efficiency, it is recommended that the south side of the house contain large glass portions to allow direct sunlight to enter the house. Also, the light should not be obstructed by shade or other buildings during the heating season from 9 a.m. to 3 p.m.
Design Blocks Working Together
To assure an energy-efficient house, the sun’s rays that have been “collected” from the south-facing windows will be absorbed and distributed throughout the house by working together with these other design elements.
The Absorber – A hard, dark surface – possibly a masonry wall, floor or water container, within the direct path of the sunlight, when the rays hit its surface, they are absorbed as heat.
Thermal Mass – While the absorber is an exposed surface, the thermal mass is the materials behind or below the surface that retain the heat.
Distribution – The retained heat will need to be circulated to different areas of the house. Sometimes appliances such as – fans, ducts, and blowers are used. However, in a strictly passive house, only natural heat circulation modes allowed are – conduction, convection, and radiation.
- Conduction – Heating an item by transferring heat from an existing hot item to something that is touching the hot surface.
- Convection – Heat circulating through gases and liquids. In a passive home design, air convection will transfer the heat from the south wall to the interior walls.
- Radiation – Allows heat to move through the air from warm objects to cooler ones. In a passive house design, two types of radiation are used – solar and infrared radiation.
- Controls – To prevent overheating in hotter months, roof overhangs, low -emission blinds and awnings are ways to shield the sun’s rays. Electronic sensing devices – differential thermostat that signals a fan to turn on automatically, and vents and dampers that restrict or allow heat flow are other options to consider.
Passive house construction is a growing green building trend and with good reason because the design elements do reduce heating and cooling cost by using the natural sunlight and heat. However, to avoid potential disasters, work with a reputable design expert, such as Chicago Engineers, who can outline all the pitfalls and advantages to your construction or remodel.
About the Author
Michael Tobias is the founder and principal of Chicago Engineers. He is a graduate of Georgia Tech class of 2004, with a Bachelor of Mechanical Engineering with honors. His innovative approach to MEP engineering comes from graduating GE’s Engineering Leadership Program, where he designed wind turbines and biofuel power plant engines. Michael’s passion within design is energy efficiency and green technology.