•A method for evaluation of solar spectrum range selection to reduce heating losses.•Case study with real data using crystalline silicon modules.•The results indicate that the optical filter should reflect radiation with a wavelength greater than 1000 nm.•The construction of a film with such characteristics is technically feasible. This paper proposes a method for evaluating and selecting the solar spectrum range to be absorbed by a photovoltaic cell to obtain a better relationship between radiation absorption for photovoltaic conversion and heating efficiency losses, in order to maximize the power generated by the cell. The methodology proposed considers the spectral response of the photovoltaic conversion technology and environmental operating conditions that affect the photovoltaic cell performance. The application of the methodology to a case study with real data from an equatorial location resulted in an optical filter that reflects wavelengths above 1000 nm. The application of this proposed filter reaches earnings between 6.8% and 1.1% in energy generated by crystalline silicon modules, depending on the reflectance of the filter.