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Kimberly Powell

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If green roofs were mandatory in cities would there be less development and building?

William McDonough knows the benefits that come from designing and implementing green roofs. McDonough has helped design living roofs for big companies such as Nike and Ford Motors. But many companies and homeowners overlook the benefits of green roofs. One benefit of green roofs is that they keep the internal temperature of a building steady throughout the year. The National Research Council of Canada found that having a green roof reduced the daily energy demand for air conditioning in the summer by 75%. Toronto is the first North American city to pass a law mandating green rooftops for all new residential, commercial and industrial developments. Any new construction with floor space of more than 2,000 square meters must devote between 20 and 60 percent of its roof to vegetation. But with green roofs comes an unwanted financial upfront cost. Will developers decide that the benefits outweigh the costs for installing green roofs?

If green roofs were mandatory in cities would there be less development and building?

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    May 24 2012: Mandating green roofs seems like a great idea to spur environmentalism, as well as help people be greener in general. I don't think that developers would have a problem following a new mandate, but I do question what the individual would think. Would purchasing a space or home that has been built with a green roof increase the up front cost, and would individuals still want to shell out the money despite the promise of 75% reduced air conditioning energy demand? For people who don't use air conditioning or heating what is the incentive to purchase a home that has a green roof, especially if it's more expensive than a traditionally built house? If new mandates don't ensure that all newly built spaces require a green roof and therefore an increased purchasing cost I fear that people will tend towards traditionally built spaces and the new spaces would go unoccupied, unless the developer covered the cost of the green roof.
    • May 24 2012: Not only are green roofs great for reducting HVAC costs but they also have implications for global climate change. If new roofs were installed on new private homes, these places would have substantially less carbon emissions than houses without green roofs. The green roofs will be photosynthesizing constantly, making them extremely beneficial. If homeowners are only looking at the short term consequences of green roofs, they might not be as appealing but all the long term benefits are so great, it seems to me like they outweigh any bad things that could arise.
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        May 24 2012: I don't argue that green roofs would be beneficial with regards to global climate change, but I question how many people are willing to pay an extra up front cost for a space with a green roof. Many ways to help the environment are simply options in current society such as being vegetarian or using LED lights rather than incandescent. If the option isn't turned into a requirement I don't believe that everyone will choose something that benefits the environment, especially if there is a larger up front cost. To me the option of buying a home with a green roof is similar to the option of buying an electric car, just because it helps the environment doesn't mean that it will be the choice of every individual, particularly if it is initially more expensive.
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          May 28 2012: I agree, if the savings from heating and air conditioning take many years to match the upfront cost of the home, people will go with the standard home that is much cheaper. I think most people are becoming more aware about the human impact on the environment, but until the cost of green technology becomes affordable to everyone, we will stick with the cheaper option that causes greater environmental harm.
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      May 24 2012: You have to remember that people who would make green roofs wouldn't be just homeowners. You have to think of a renting scenario as well, apartment complex owners, hotel owners, etc. For someone who owns an apartment complex with a green roof, they could charge a bit extra for the green roof and make a bit more profit in the long run, and as a renter that would be justified because you save on heating/cooling costs. There is an incentive for both the building owner and the renter.

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