The PDB Home is designed to the Passive House standard which is 100% energy performance based.
This allows for very simple and straightforward performance targets to aim for when designing. How you meet these requirements depends on your climate, building type, economics, and architectural design. The following list outlines the three requirements needed to achieve the Passive House standard.
- Airtight building shell ≤ 0.6 ACH @ 50 pascal pressure, measured by blower-door test
- Annual heat requirement ≤ 15 kWh/m2/year (4.75 kBtu/sf/yr)
- Primary Energy ≤ 120 kWh/m2/year (38.1 kBtu/sf/yr)
According to U.S. Government Energy Information Administration, the average home in the US consumes 145 kwh/m2/year to heat and cool their residents. Our homes are meticulously modeled and constructed to consume 15 kwh/m2/year to heat and cool the residents - 90% less heating and cooling energy than the average american home.
How much energy do our houses consume?
How do we achieve superior comfort levels all while consuming 10% of the energy required to heat and cool our homes? The following topics outline the various measures we undergo to achieve the Passive House standard.
Superior Building Envelope
The Passive House concept all begins with a super-insulated, air tight, exterior building envelope that is free of thermal bridges, cold interior surfaces, and drafts. A thick insulation layer is critical for keeping the heat inside during the winter, and the heat outside during the summer. Air tightness is also essential for the success of the design. We spend money to heat, cool and filter our interior air. There is no use in allowing all that conditioned air to escape to the exterior! We like our buildings wrapped with a thick, airtight blanket to keep our utility costs low and our interior comfort levels high.
Our motto at Prairie Design Build is, ‘Build it Tight, Ventilate Right.’ Because we construct our building envelope so tight, we must bring in fresh clean air through a controlled ventilation system. This system is called an energy recovery ventilator, or a heat recovery ventilator, often referred to as an ERV or HRV.
Passive House ventilation systems exhaust air from the bathrooms and kitchens. This is where most of the interior odors and moisture build up, and must be removed. Fresh, clean, filtered air is supplied to the bedrooms and living spaces, where occupants spend most of their time. Fresh air is consistently delivered, where you need it, all the time. By using an ERV or HVR, up to 90% of the sensible energy in the exhaust air can be captured by the incoming fresh air – Very smart!
In a Passive House, long gone are the days of over-sized mechanical systems used to heat and cool our buildings. We size our mechanical equipment based on the heating and cooling loads of the building. The heating and cooling loads are so small in a Passive House, up to 90% less compared to built-to-code construction! With such tiny loads, we can use very simple and efficient mechanical equipment to achieve superior comfort levels.
Heat pumps are the most efficient way to heat and cool our buildings. Geothermal is a heat pump, but a very expensive heat pump, and often too large for a single Passive House. Instead, an air-to-air heat pump is what most Passive Houses use to heat and cool. No more burning gas in your house!
We cannot forget about our biggest energy source on earth, the sun. With proper design from the very beginning, we can heat our buildings with the power of the sun. In many cases, southern windows can generate more energy for our heating needs than a photovoltaic array can generate electricity. Did we mention that the sun’s energy is free? Love the sun.