Q: What does “green building” mean and what does it mean for a building to be certified?

A: Green Building can mean a variety of things to different people.  Green to some people might mean targeting energy or water efficiency.  Others might target indoor air quality or green materials like those with recycled content.  All of these elements are green, but the question of  how green they make a building is where a certification system like LEED comes into play.  Not only does a certification help to quantify what has been done in a variety of areas, it also makes sure that all of the most important areas that make a building green have been addressed through prerequisite credits and minimum performance standards.  Buildings that are certified under the rating system have had a third party review of the project to make sure that the standards outlined through design are what is actually installed.  This type of rigorous review process helps insure the integrity of the certification system and gives weight to the LEED certification standard.

Q: How much of a building or what percentage of a building deems it “green” or certified “green”?

A: Programs like LEED are designed to address the whole building. Some credits, like those associated with materials, have percentages attached.  Others, like the some of the prerequisite credits, must be achieved throughout the entire building, and still others may have some flexibility in where the “green” elements are located. An example of flexibility in application would be that some areas of the building may require a higher energy use due to the needs of the facility, but that higher use should be offset by a lower use somewhere else in the building. Thus, buildings that are certified through LEED must demonstrate that they have met the minimum targets for the whole building in a variety of areas, but the rating system acknowledges that not every component will be “green” and flexibility in how credits are targeted provides a mechanism and guidance for project specific elements.

Q: How much more expensive is it to build a house green versus a traditional build?

A: Costs can vary widely depending on the scope of how green a project intends to go. Costs need to be looked at on a system-wide basis, as more expensive improvements in one area may create cost reductions in another. For example, spending money on better building envelope performance can affect how air conditioning systems are sized and perform, and can potentially reduce some of the initial costs as well as long term operating costs. In general, base level green buildings that meet the minimum performance standards associated with LEED should be able to be constructed with little additional cost increase, while more extreme buildings, such as a LEED Platinum building, will have a much higher premium associated with initial construction but also lower operating costs. Understanding tax incentives and rebate structures is also an important element when analyzing the costs. For more information you can read my article, “Paying for Green”. Additional studies and articles can be found in the peer reviewed articles on the USGBC website.

Q: I am already planning to build a “green” house. How much does it cost to get it certified and what benefit is there to going through the certification process?

A: Typically, residential certifications end up costing less than one percent of the construction costs, but that figure can vary according to project team experience and level of building performance testing or consulting required. The LEED certification provides the client with a valuable tool for analyzing the building as a whole and making sure that all critical areas are looked at from durability planning and water efficiency, to energy performance and indoor air quality. Using a Green Rater to actually certify the home provides additional value because a third party is now inspecting and performance-testing the home to make sure the targeted goals are achieved and items in the plan are implemented. A keen understating of building science and the ability to identify items that will affect building performance are important components of the Green Rating process. Once the certification is complete, the project team has a third party certification that verifies that the home met the required standards, and this statement can potentially provide additional value in marketing, sales, and dispelling green washing.