The control of temperature is a critical factor that contributes to the success or failure of many reactions in synthetic chemistry. Despite this, very little attention has been paid to temperature as a variable in both photocatalytic reactions and reactors with little description of internal temperatures in the literature, leading to difficulty in the reproduction of exact conditions. Svejstrup et al recently described the light intensity and temperature data for a number of commercial photochemistry reactors. They concluded that for the next generation of photoreactors, accurate control of light intensity and reaction temperature would be highly desirable. More recently we described the design and development of a lowcost 3D printed CDR that could be used for continuous flow photochemistry. In that publication we demonstrated that light intensity, as a function of distance from the light source, correlated with conversion using a photocatalysed bromination reaction. In this publication we now wish to describe our recent development in controlling the temperature of the photo-CDR under an LED light source. This was achieved by designing a 3D-printed holder for the CDR which uses compressed air for the cooling and temperature standardisation of the reactor. For consistency of temperature measurements, we designed a modified photo-CDR that included a recess in the centre to locate a temperature probe so that we would have a greater record of the temperature of the solution in the photo-CDR. All files for the reproduction of components exemplified in this paper are provided with links to the files in stl format in the supplementary information. Modifications were made to the design of the reflective lamp holder to include a distribution point for a stream of compressed air that was designed to flow both below and over the surface of the reactor and the mirror base of this apparatus in order to maximise the light intensity focused on the photo-CDR and minimise heating from the lamp. Previously we showed that the lowest distance from the lamp and inclusion of a mirror to reflect the light passing through the photo-CDR, led to the highest conversion in our standard reaction. We sought to investigate the temperature that would be observed under these optimum conditions and whether we could lower and control the temperature in order to avoid elevated temperatures leading to undesirable side reactions that would also be applicable to scaleup synthesis. Our desired aim for the air-cooled lamp holder was for it to be amenable to 3D printing to enable it to be low cost, analogous to the photo-CDR itself. The photo-CDR was printed in polypropylene due to its transparency to blue-light and its chemical resistance.