Green Roof Cost Savings

The largest reductions were seen in rooms directly below the green roof and no reductions were found more than three floors down.

Green roof cost savings. An extensive green roof is the most common and least expensive type of green roof with costs ranging from 10 20 a square foot 2. The green roof provided an annual energy saving of 1 6 in cooling and 0 5 in heating. 1 2 in addition green roofs can reduce building energy use by 0 7 compared to conventional roofs reducing peak electricity demand and leading to an annual savings of 0 23 per square foot of the roof s surface. The university found that the green roof would cost 464 000 to install versus 335 000 for a conventional roof in 2006 dollars.

All these come at an extra cost. Over its estimated lifespan of 40 years a green roof would save about 200 000 of which nearly two thirds would come from reduced energy costs. Based on these considerations recover green roofs has found that extensive roofs can cost about 10 to 50 per square foot while intensive roofs can cost from 20 to 200 per square foot. The u value of the roof was reduced from 0 59 to 0 42 with a green roof and 0 38 for the green roof with water storage.

Over its lifetime though the green roof would save about 200 000. They are fairly lightweight and can be installed on roofs with a pitch from 0º to 30º. Calculating the average cost of green roofs can be difficult because there a number of variables not just the size and accessibility of the site but the types of plants that are going to be grown on it. The economic benefits of any individual green roof will however depend on its design geographic location surroundings and the building itself.

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. Finally there is also ongoing costs to consider for maintenance and repairs. Ecoroofs are expected to be an important part of the city s urban strategy as it grows and density increases in the decades to come. They consist of a thin layer of soil with continuous coverage of growing material.

1 3 these temperature reduction and energy efficiency benefits are a key contributor to the growing popularity of green roofs in the. Cost benefit evaluation of ecoroofs 2008 pdf 37 pp 2 1 mb about pdf this report attempts to quantify the private and public costs and benefits of green roofs or ecoroofs in portland oregon.