Sales may be slowing for distributors of HVAC products.

After 10 months of strong growth, average sales among Heating, Airconditioning and Refrigeration Distributors International member companies in April were up less than 1 percent from year-ago levels, according to the group’s Targeted and Regional Economic News for Distribution Strategies report.

Distributors in the association’s eight North American territories were widely varied, with some companies reporting sales increases up to 8.6 percent and others declines of 11.7 percent.

Inventory levels were also generally higher than 2010 figures, the association reported.

“The construction markets for commercial and single-unit housing have failed to make substantial gains so far in 2011, and this is no doubt having a negative effect on member sales,” said HARDI’s chief economist, Alan Beaulieu of the Institute for Trend Research. “After five consecutive months of same-month sales growth versus last year, sales in April were flat. It has been traditionally difficult for member sales to improve when the market for new single-family homes is stagnant, but some opportunities for growth can be found in the smaller, but booming, multiunit housing market, up 39 percent from last year and growing.”