“A sales decline during May is not unexpected since the cooling degree days were off by 25% from last year,” said Brian Loftus, HARDI’s macroeconomic and residential market analyst, in a press release. “Another drag on the sales growth was this May had one less billing day than May of 2024. With the same number of billing days, we estimate the sales growth was better than 2.5%.”

The monthly sales survey also calculates distributor’s Days Sales Outstanding (DSO), a measure of how quickly customers pay their bills. “The DSO turned at 37 days during May of 2025 after being close to 40 days for the month from 2021 through 2024,” said Loftus.

The underlying trend of the HARDI distributor sales growth during 2025 has been a nice improvement versus last year, the press release said. “After adjusting for the same number of billing days, the rolling three-month average monthly sales growth has been in the 5% to 6% range so far this year versus the 2% area last year,” said Loftus. “But so far this year inventories have been growing faster than sales. Hopefully those boxes begin to melt away now that summer has arrived.”

HARDI members do not receive financial compensation in exchange for their monthly sales data and can discontinue participation without prior notice or penalty. Participation is voluntary, and the depth of market coverage varies from region to region. An independent entity collects and compiles the data, which can include sales information about products not directly associated with the HVACR industry.