Residential houses have come a long way in reducing their energy footprint. According to the U.S. Energy Information Administration, homes built after 2000, consume only 2% more energy than older homes, despite being 30% larger. While that is certainly encouraging, advocates of the Passive House movement believe that there is a lot more that can and needs to be done - not just to reduce energy costs, but also, to help reverse global warming.

The premise of the Passive House concept is simple - building homes with strategically placed windows, doors, hallways and vents that allow it to function efficiently using natural energy sources. A great example of this concept is the Park Passive house in Seattle, Washington. Built in 2013 by NK architects, it was initially touted as a super energy efficient home that 'could be heated with a hair dryer'.

Though that was a slight exaggeration, the energy statistics are extremely impressive. Park Passive House uses 80% less energy than a similarly-sized conventional home. Also, the efficiency has been achieved without sacrificing style or comfort. The 2,000 square-feet, three-story home seems to have it all - four bedrooms, three bathrooms, a large double-vaulted kitchen, a children's play area, as well as dedicated living and dining rooms.

So how did the architect do it? With the help of well insulated walls, high performance windows and doors, as well as a heat recovery ventilator that all work in perfect harmony to help keep cold air out in the winter. During summer, shading devices protect the windows from the intense sun, helping reduce the impact of the heat. To further cool the home, vents and doors can be opened and adjusted as needed. With these simple solutions in place, Seattle's first certified Passive House is able to maintain a comfortable temperature through all seasons, without the use of an active heating or cooling system.

What's even more amazing is that the Park Passive house does not even have solar panels installed yet. When that happens, its energy usage will reduce drastically, allowing the well-designed home to reduce its energy footprint, even further.

Unfortunately, despite these impressive statistics, there are currently only 90 certified Passive Homes in the entire USA. This is partially because in order to be certified by the Passive House Institute US, the homes have to undergo a series of rigorous tests. This is no easy task given that all Passive homes have to demonstrate the same energy efficiency, irrespective of the weather patterns they are exposed to. However, the biggest impediment to the growth of Passive Housing is the cost, which runs about 30% higher than that of conventional homes. For most U.S. homeowners, the energy savings is not enough to justify the extra cost.

But there is hope. The Passive House Institute US is currently working on new standards that will take into account climate variations. This means that building a Passive home in the hot humid Southeast US will be held to different standards than one constructed in the colder Northeast part of the country. This will hopefully encourage more people to build the homes, which in turn, will help bring the costs down.

Things are a little different in Europe, where almost 65,000 such homes already exist and many more are currently under construction especially in Germany, where the movement first began. The city of Brussels is rewriting its building code to reflect passive standards. The popularity can be attributed to the higher energy costs which makes switching to Passive homes more cost effective. Also, since the weather patterns are similar in many parts of Europe it is much easier to emulate a successful Passive House model. Hopefully, the USA will also start seeing a similar uptrend in these super energy efficient homes.

Resources: gizmag.com,archdaily.com, passivehouse.us