LEED vs Green Globes: An MEP Point of View

By Paul Johnson, P.E., LEED AP BD+C

This article is part of Wood Harbinger’s newsletter series.

Washington State has a history as a staunch supporter of sustainable design. We were the first state to make green building the law in 2005, requiring that publicly funded major facility projects attain at least LEED Silver certification. There are exceptions, such as schools, projects under 5,000 square feet of conditioned space, or renovations under 50% of assessed value. There are also other exceptions based on building type, such as pumping stations and research facilities. But many major projects must be measurably sustainable.

LEED has dominated the national sustainable certification landscape, but Green Globes is putting on the pressure and offering an alternative. As you may or may not know, Washington State retained Senate Bill 5384 in 2010, which allows the use of Green Globes (GG) in lieu of LEED for measuring the sustainability of a building. The Washington State mandate for minimum LEED Silver certification can also be met by achieving Green Globes standard. In another move towards opening the certification field, the U.S. General Services Administration gave its blessing to Green Globes in October 2013, now recommending either LEED or Green Globes be used as the sustainability metric for federal projects. The net result is that both metrics are now nationally accepted green rating and certification tools for federally funded projects, and give private facility owners a vetted choice for reducing the environmental footprint of their buildings and receiving an independent source certification for their sustainable efforts.

There are umpteen articles* comparing the two metrics, looking at pricing, ease of use, scoring, and sustainable impact. Without rehashing all the details and similarities between them, LEED v4 and Green Globes have two primary things in common: they raise the awareness of sustainability as applied to the built community and provide a measuring tool to determine the level of sustainability.

As a mechanical and electrical engineering consulting firm, the systems we engineer have a major influence on the sustainable operation of a building over time, and both LEED and Green Globes affect our design decisions, our workflows, and the overall outcome of our contribution to a building.


LEED’s newest version includes modifications in the prerequisites and credits applicable to MEP.

Water Efficiency: LEED has removed one prerequisite for minimum water use for health care and added two. These new prerequisites require reduced landscape water use by 30% and to be able to measure whole building water use. Typically, the whole building water use measuring isn’t hard to do with a utility meter for the site, and a separate sub-meter for the irrigation. The sub-meter can be deducted from the main meter to get the building consumption.

Other credits have been adjusted to require WaterSense labels on certain fixtures. This will influence the mechanical engineer to ensure the correct fixtures are selected and installed to meet this requirement.

Energy and Atmosphere: Since Wood Harbinger also provides commissioning, the several items added to the prerequisite for commissioning will have certain impact. These include preparing an Operations and Maintenance Plan, starting the CxA’s involvement at the end of DD, and design review of the building envelope. These items will add time and cost to the Owner and consultant. If an owner opts for enhanced commissioning, more effort will be required for monitoring systems, envelope commissioning, and operator training.

In addition, a new Advanced Energy Metering credit has been included. Interestingly enough, the WSEC requires major systems to be sub-metered and monitored through a building energy management system (DDC). This will be an additional effort for the MEP consultant, but will be required no matter what.

Indoor Environmental Quality: Several items have been modified under this category that affect MEP. The biggest one is outdoor air. This is, in my opinion, a negative impact area. Some studies say that personal performance is enhanced with improved air quality, but a definitive value has yet to be determined. Obviously, indoor pollutants are not healthy, but in general, CO2 control provides a measurable method of ventilation air control that is adjustable and controls the energy use associated with increased ventilation. Local exhaust systems usually cover specific pollutant issues, and most other air quality issues are handled through general ventilation.

The credit for increased ventilation, although now moved to Enhanced Indoor Air Quality Strategies, has always troubled me, since it negatively affects energy use. Getting a point or two for this item requires a fair amount of effort for the consultant, but in my opinion shouldn’t be allowed in the first place. This should be a controlled and monitored design element per code, not a point on a chart.

The new credit for Acoustic Performance, requiring additional sound attenuation, also affects the MEP design. Although Wood Harbinger has extensive experience with noise-level mitigation from our school design experience, this is an added effort for MEP consultants as it is applied to other building types. This typically increases duct size, fan selection, and energy use. All these require more space, more upfront equipment cost, and continued increased energy cost, not to mention additional coordination by the mechanical engineer.

Green Globes

Green Globes addresses some of the same parameters in water efficiency, energy, and indoor environmental quality.

Water Efficiency: Labels are not required on fixtures and savings are already certified by the tested fixture showing they save water. Although sub-metering is not required by Green Globes, local green or mechanical codes are now requiring sub-metering and monitoring of flows.

Energy and Atmosphere: Green Globes includes sub-metering categories for individual systems and equipment thresholds that can receive points for M&V. Again, the WSEC requires major systems to be sub-metered and monitored through a building energy management system (DDC), so sub-metering is becoming the norm and will have design impact on the MEP consultant.

Indoor Environmental Quality: Both LEED and Green Globes utilize ASHRAE Standard 62.1-2010 for baseline ventilation requirements. However, Green Globes does not recognize increased ventilation as an additional point, presumably for the reasons that I discussed above regarding energy use.

Green Globes already had an indoor noise assessment criteria with points applied to multiple building types, so we now see like effort required by the MEP on this front.

The Benefit of Competition

Many articles and bloggers note that a competition between the two is good for the industry. I haven’t quite determined in my own mind what that competition is. Is it to see which is better in the sense of ease of use?  Green Globes is simpler, costs less, takes less time, and provides similar sustainability certifications exemplifying a building owner’s commitment to sustainability. LEED is continually changing requirements, becoming more stringent and charging more money to review and re-review submissions. Is the competition over which provides the most sustainable outcome? Green Globes does look at different categories such as project management, measuring another input towards sustainability. However, both use a point system to evaluate the outcome. Green Globes has a 1,000 point total and LEED has 110 points. In this respect, I believe they are both of equal value in measuring a sustainable outcome.

* Here’s a few recent ones:

LEED vs. Green Globes: How to Choose,” by MulvannyG2’s Stuart Hand, published by the Seattle DJC on February 27, 2014.

LEED vs. Green Globes,” by Steve Law, published by the Portland Tribune on November 14, 2013.

Competition for LEED: GBI’s Green Globes Shakes Up Building Certification,” by Jennifer Whelan, published by ArchDaily on May 26, 2014.


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