During World War II, the company also built electric water heaters. Tops and bottoms for each unit were molded from cast iron, metal jackets formed, and heating elements made at the company's Little Mary Street plant.
In March of 1947 T.C. (Carl) Harkleroad took complete ownership of the company; purchasing from his brother Fred the land, building, equipment and the name, which at that time was Harkleroad Brothers Sheet Metal Workers.

In the early 1950's, T.J. Harkleroad entered into partnership with his father. Carl retired in 1960 and T.J. was later joined in the business by two of his brothers, Tommy and Jimmy. Tommy worked at Harkleroad Brothers unitl his death in 1995.