Passive House Standard

INTRODUCTION

The Passive House concept is today's highest energy standard promising to slash the heating energy consumption of buildings by an amazing 90%!

Data from the U.S. Energy Information Administration illustrate that buildings are responsible for almost half (48%) of all greenhouse gas emissions annually. Seventy-six percent of all electricity generated by US power plants goes to supply the Building Sector (Architecture 2030). This makes the Building Sector the largest contributor to Global Warming pollution.

The answer to homeowners who are personally committed to reducing their own CO2 pollution and offsetting the rest to become carbon neutral is the Passive House. Now is the time to take personal action and contribute to solving the climate crisis. As individuals we need to ambitiously turn down the emissions level before we reach the tipping points that scientists like James Hanson are worried about. The Passive House offers us the solution. It is the single most powerful building concept available to curb greenhouse gas emissions. It is available in the US today, is cost effective and provides the highest comfort level.

Here is how it works: In essence we employ two strategies. First we go to any length to minimize heat losses and second we maximize free heat gains.

FIRST MINIMIZE HEAT LOSSES

We wrap the building in an uninterrupted super-insulated envelope. This thermal envelope typically has 3 to 5 times as much insulation as a conventional home that meets energy code requirements. Construction details are carefully considered to prevent thermal bridging between the interior and exterior. Techniques such as a fully insulated, thickened-edge slab are used to prevent heat losses to the ground.

The windows and doors of the house must also be insulated. Triple-pane windows with insulated frames are necessary, otherwise the windows and doors act like holes in the super-insulated bucket. The windows must be carefully selected to absorb a high amount of solar heat in the south while preventing this heat from escaping with super-insulating glass. (A properly designed overhang prevents summer overheating).

We then wrap the building with an air barrier which is also carefully detailed to make a house which is 8 times tighter than a conventionally accepted “tight” house. The tightness of this air barrier is verified after construction with a blower door test.

In order to provide fresh air to the interior we use heat recovery ventilation. This ventilation system salvages up to 90% of the heat in the air that it transfers between interior and exterior while also filtering this air, providing superior indoor air quality. These systems have been praised by those who suffer from allergies and asthma. The system runs silently 24 hours a day, replenishing the interior air volume 9 times daily. (See PDF brochure for ventilator)

With such an efficient building envelope, we have reduced our heat demand to an incredibly low level. Now we can focus on the next step….

THEN MAXIMIZE FREE HEAT GAINS

Everyday the sun sends a huge amount of heat to our planet. This energy grows forests, creates weather patterns, and it can easily heat our highly-efficient house. With properly designed windows, the sun is now our primary source of heat. And it’s absolutely free! And when the sun decides not to shine, we rely on a high amount of thermal mass in the building's interior which acts as a battery, releasing the sun's heat from previous days. This thermal mass, combined with the mechanical ventilation that distributes air throughout the house 24 hours a day, also prevents overheating.

With our house so well equipped to absorb and then conserve solar energy, we need only a small supplemental source of heat. Even the smallest conventional furnaces are too large. We use a heat source that provides about the same amount of heat as a large hair dryer! This heat can be from virtually any source (an electric coil as in a hair dryer, a small gas fireplace, a highly efficient pellet stove, or radiant floor heating). Additionally, we use the mechanical ventilation system to distribute this heat throughout the house, providing comfortable and even temperatures in every room.

With such a Passive House winter energy bills will make you think the meter man read the numbers wrong when they are only ten percent of what you would normally expect. This cost savings, which lasts indefinitely even as fuel costs rise year after year, combined with the cost savings of eliminating a conventional furnace, offsets the upfront investments in the thermal envelope. These initial investments are typically recouped within a few years, and then year-after-year the Passive House saves you money because it is energy independent. And what's more your Passive House dramatically reduces carbon emissions… a priceless investment which will continue to perform for generations to come.

For more information on Passive Houses and related issues:

http://www.passivhaustagung.de/Passive_House_E/passivehouse.html

http://en.wikipedia.org/wiki/Passive_house

http://www.architecture2030.org/news/news_2_2006.html

PASSIVE HOUSE CONSTRUCTION PHOTOS

superinsulated envelopes with TJI and advanced framing technique

superinsulated TJI frame wall with blown- in cellulose insulation

blown- in cellulose

super energy efficient

triple pane windows with insulated frames

heat recovery ventilator with air to air heat exchanger recovering up to 70% of the heat of the exhaust air

air tightness verification with a blower door test