•Currently, the air channel of SAH were mostly used serpentine flux paths composed of spoilers.•The sharp turn of 180° could create eddy current in the flow path and form “dead zone” during the flow process.•It reduces the ability of heat convection between the absorber plate and air in solar air heaters.•Therefore, the spiral solar air heaters (SAAH) is proposed in this paper, in which there is only a 90° turn of the channel.•Based on this design, pressure and power consumption of fans can be reduced and heat convection can be enhanced in SSAH. A new type of solar air heaters was proposed by using the spiral shape of spoilers instead of the serpentine shape. The function of the spiral solar air heaters (SSAH), including heat collection efficiency, temperature differences between inlet and outlet, irradiance, and air volume were experimentally studied in this paper. According to the testing, the difference of temperature between inlet and outlet is related linearly to irradiation, and heat collection efficiency is related the quadratic function relationship to irradiation with a constant flux. Finally, the heat loss coefficient of the SSAH is determined by the normalized temperature to be 5.69 W m−2 K−1. Compared with the conventional and serpentine SAH, this kind of solar air heaters had a higher heat collection efficiency.