Aim We compared potential differences in drug delivery between different valved holding chambers (VHCs) used by asthma patients, with and without facemasks. Methods An in vitro study design was created using a fluticasone propionate (FP) pressurised metered dose inhaler (pMDI) connected to a VHC. VHCs without facemasks and with sealed and unsealed facemasks were placed against face models that mimicked the features of a 1‐year‐old infant and a 4‐year‐old child. We analysed the amount of FP deposited on the filter in the face model after five breaths with a tidal volume of 75 mL. Results Our measurements showed significant differences in the amounts of FP deposited on the filters, even without facemasks. The amount of FP delivered through the VHC and facemask combinations differed significantly, depending on the degree of the lack of facemask to face seal. All the tested VHCs showed significantly better drug output without a facemask. Conclusion The VHC and facemasks chosen had a considerable and significant impact on FP delivery. The facemask seal should be checked whenever a VHC facemask combination is used. Young children should be taught to use the VHC mouthpiece as early as possible to optimise FP delivery and achieve more effective asthma therapy.