Needleless electrospinning can produce nanofibers on large scales, which is promising for industrial manufacturing. It is known that solution temperature is an important parameter for electrospinning. However, the influence of solution temperature on needleless electrospinning has not been reported much in the research literature, nor has the application performance of needleless electrospun nanofibers. In this study, using a curved slot as the needleless electrospinning spinneret and PVA as the material model, we show that solution temperature has a considerable effect on fiber diameter, packing density of nanofiber mats, and fiber productivity. Increasing the solution temperature from 20 to 60 degrees C can lead to finer fibers with a larger fiber production rate. The nanofiber mats produced at higher solution temperature show increased air filtration efficiency. Increasing solution temperature may form a new strategy to improve nanofiber productivity and meanwhile increase nanofiber quality.