Outdoor air can contain contaminants that lead to unhealthy working or living conditions. You may need to assess the quality of the local outdoor air before bringing it indoors. HHigh efficiency MERV filters (13 or higher) are one solution to treating poor-quality outdoor air before supplying it to the indoors. This can be part of a strategy for achieving EQc5: Indoor Chemical and Pollutant Source Control.

Determine the best ventilation strategy for your building: natural, mechanical, or mixed-mode ventilation. The choice of ventilation system is more likely to be shaped by the LEED minimum ventilation prerequisite (EQp1) and increased ventilation credit (EQc2), not this credit.

Make final calculations of the estimated building energy loads. Confirm that renewable energy generation capacity is 2.5% of building energy, at minimum for the LEED credit, or that the project’s goals are met.

Conduct a preliminary cost-benefit analysis to determine the first cost and life cycle payback. Most teams use LEED point thresholds as a way to frame the analysis. For example, what is the cost and the payback of meeting the 2.5% threshold?

Start by reducing the building’s energy load. The smaller the load, the less renewable energy you have to generate to meet the credit thresholds, which saves money and might expand the options you can use. For example, a 100-MMBtu/year building needs to produce 2.5 MMBtu/yr to reach the 2.5% credit threshold, while an 80-MMBtu/year building needs only 2 MMBtu/year.

The refrigerant charge is typically calculated automatically in the LEED Online submittal template. It is the relationship between how much refrigerant is needed (in pounds) and the cooling capacity (in tons) of the equipment.

This credit involves the use of an Environmental Impact Calculator & USGBC Credit Calculator which will be available for use by projects participating in the pilot. USGBC has not made it available for public viewing. To access the calculators, register your project for the credit (see Resources).

The default leakage rate used in the credit form calculator is 2%, and the end-of-life refrigerant loss value should be 10%. If your project has equipment with different leakage rates, those values can be used instead. 

Even one piece of equipment can tip your calculations to compliance or noncompliance. Use the calculator in the LEED Online submittal template to run calculations from the beginning of HVAC system selection (note that your project has to be registered through LEED Online to download those forms). This gives a sense of how far from compliance a system may be; teams then get a better idea of how significant a change may be required. Note that annual leakage and end-of-life refrigerant loss rates are set to defaults but can be edited if needed. 

If your project building is connected to a district chilled-water system, you have to include all the chillers in that system in the calculations, even if they are outside your project’s scope or control. As a rule of thumb, if the system is serving your LEED project it should be included in calculations, whether it is within your project scope of work or not.