How To Green Roofs Save Energy

Green roofs do provide potential energy savings by improving building insulation characteristics.

How to green roofs save energy.

Determining the heat gain loss of a green roof on a structure is tricky given other influences such as weather conditions or outside temperature the green roof composition and any existing site conditions. There are multiple factors that contribute to the sustainability and efficiency of green roofs. 1 3 these temperature reduction and energy efficiency benefits are a key contributor to the growing popularity of green roofs in the. If you re considering energy efficiency upgrades for your roof you should think of upgrading your attic as part.

Green roofs not only help reduce the urban heat island effect by covering conventional dark roofing surfaces with vegetation which absorbs less heat but they also use solar radiation to evaporate water from the growing media and transpire the absorption of water through a plants roots and release of it through its leaves as a vapor moisture from the plants. No the plants on top of your house won t produce energy or at least not the kind you ll need to run your microwave but what they will do is help reduce your cooling costs during hot summer months source. Figures attributed to zinco estimate that 2 litres of fuel oil are saved per m2 of green roof per year. Although a little more difficult to quantify in terms of roi energy savings is a direct benefit of green roofs.

When it comes to cooling green roofs also help because natural plant and soil processes reduce the level of solar energy that is absorbed by the roof s membrane. Insulate for added energy efficiency. Secondly the plants that make up the outside layer of the system protect the inner roof layers from uv rays. Green roof temperatures can be 30 40 f lower than those of conventional roofs and can reduce city wide ambient temperatures by up to 5 f.

Yet it is difficult to give them a fixed u value rating. This is because green roofs are dynamic systems and their properties vary throughout the year. If the insulation in your attic or under your roof is not up to snuff you re still likely to have a problem with unwanted heat. First the multi layered roofing systems insulate the building against heat and reduce costs of cooling the building.

In contrast asphalt shingles store and retain more heat in the summer. The plants create natural insulation which means that there is less need to rely on heating and cooling systems to moderate interior temperatures. Likewise in the summer an air gap prevents the heat of the sun from warming up the attic and the rest of the home. Studies in germany have provided various estimates.

Installing attic fans and rafters can also encourage air circulation in a way that will bring down temperatures beneath your roof. An energy efficient roof makes a huge difference but it can t do all the work.