Because the green building industry is so new, there is a lack of industry experience and a general lack of understanding and agreement on the added costs to make a new building “green”.  Some sources have claimed that there is no additional cost, and other estimates range to over 10% of the base building cost.

Design Fees

First, the level of effort from the design team is much greater for a green building than for a standard “code compliant” building.  There is much more interaction among team members as part of the Integrated Design Process that is needed to achieve building-use objectives and green targets at the same time.  The design evolves as the various specialists negotiate and educate each other on trade-offs and compromises.  Each will spend more time than they would on a standard building where the architect sets the broad parameters and the other professionals work independently on their specialties.  In one specific example, someone on the design team (usually the mechanical designer) will have to perform a software energy simulation.

One extra line item that will appear on the project budget is the LEED facilitator, an added role to coordinate the design process and help the Owner make informed decisions to resolve conflicting priorities.  The LEED facilitator is also responsible for maintaining and expediting the substantial record-keeping task involved in all LEED projects.

A LEED consultant will base their fees on the number of hours expected to complete the project.  A very low quote may mean that the consultant has underestimated the time needed to complete the job.  A very high quote could mean they don’t have systems and processes in place to execute the job efficiently or they’ve added a contingency to allow for a lack of green experience on the design team.  As a guideline, the following sources have done market research to help owners anticipate the cost of a LEED Facilitator:

• US General Services Administration, Oct 2004, Document GS-11P-99-MAD-0565, pp.6, 403-406; Rates are US$65/hr to US$150/hr depending on team member used.  Total cost of LEED Facilitation:  LEED Certified $110,540; LEED Silver $111,840; LEED Gold $127,240.

• Northbridge Environmental Consultants, April 2003.  Range of 0.5% to 0.9% of total project cost, with 0.7% as best estimate.

• The Brendle Group, 2004.  $60,000 for LEED documentation.

Construction

By their nature, green buildings must not be “over-designed”.  Because redundancy and oversizing leads to material waste and energy waste, the design team strives to make sure that systems and equipment are sized carefully to meet the requirements.  This tends to drive down the cost of green buildings.  However, there are other factors that tend to increase the cost, such as:

• Higher design fees (discussed above)
• More expensive materials in many cases
• More construction management allowed for documentation
• Added tasks (construction site recycling program, air flush procedures, more careful commissioning of mechanical systems ...).

Overall we believe that a LEED building costs a bit more than a standard building, and this is borne out by the research referenced below.

• Kema Green Building Consultants, 2004.  LEED Certified 0 to 2.5% on project cost; LEED Silver 0 to 3.3%, LEED Gold 0.3 to 5.0%, LEED Platinum 4.5 to 8.5%.
• David Langdon, July 2004. Overall cost increase of 1.0%to 10.3%.
• National Conference on Building Commissioning, May 2007, p.4.  Overall cost increase of 1% to 6%.

We know that those extra costs can be contained at the design stage by following some basic principles.

1. Nail down and document the functional requirements of the building early.  Make room for early input from the mechanical, electrical, and LEED consultants even before the site plan is prepared.
2. Make sure everyone on the design team understands their responsibilities with respect to the LEED process and is committed to an Integrated Design Process.
3. Very systematic and professional management at the design stage as well as the construction stage.  Online collaboration tools are an excellent aid.
4. Keep the mechanical / electrical systems as simple as possible.  Avoid complex technologies that have little chance of being operated correctly once the building is occupied.
5. Keep the owner engaged and informed, understanding the nature and impact of decisions being made to achieve competing goals.

More effort on the design will lead to fewer problems and lower costs overall.  Buildings at the higher end of the cost scale will be those that didn’t follow these fundamentals of green building design.