Specifying high-quality equipment with a long lifespan can reduce environmental impacts, since most leakage occurs during installation and decommissioning. For information about the service life of different types of HVAC equipment, refer to the 2007 ASHRAE Applications Handbook—HVAC Applications. (See Resources.) 

The refrigerant charge is typically calculated automatically in the LEED Online credit form. It is the relationship between how much refrigerant is needed (in pounds) and the cooling capacity (in gross ARI-rated tons) of the equipment.

Complete credit calculations based on the finalized mechanical system design.

Note that this credit requires the weighted average of all refrigerants to be less than 100, even if, individually, some are higher. That’s why it’s important to run the calculations several times until the final equipment is selected for your project. 

All refrigerants involve tradeoffs. HFCs, for example, don’t contain chlorine and have zero ozone depletion potential, but they have significant global warming impact. HFCs are also less efficient than conventional, chlorine-based refrigerants, which are the most damaging to the ozone layer. Ammonia is highly efficient and ozone safe, but it can be hazardous to human health if released in large quantities.

There are trade-offs with all refrigerants. R-410A, for example, has a lower refrigerant charge, defined as the ratio of refrigerant to gross cooling capacity, but it uses more energy which may increase operating energy costs and will have a negative impact on your compliance with EAc1: Optimize Energy Performance, and total energy use reduction for the project. 

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. 

Common split systems use varying refrigerants, in a range of quantities and leakage rates. These systems can have a hard time meeting the threshold for credit compliance because their leakage rates are high. Check your specifications early in the design stage and investigate these products if you’re thinking of using split systems. 

Packaged terminal air conditioners (PTACs) typically use refrigerants with a high environmental impact. These units may make meeting the credit requirements more challenging, especially for hotels and multifamily residential projects, which tend to use them. The industry has been moving toward upgrading these refrigerants, so check with manufacturers for recent upgrades to their products. Newer refrigerants may help credit calculations. 

Check multiple equipment manufacturers to see what refrigerants they specify for their equipment. There may be a variety of system types that will help meet the credit requirements in a variety of ways.