Densities were measured over the entire range of composition and at atmospheric pressure for the three binary mixtures of water, 2,2,2-trifluoroethanol, and 2,5,8,11,14-pentaoxapentadecane (tetraethylene glycol dimethyl ether) al temperatures T from 283.15 K to 333.15 K. The experimental Values were fitted by an empirical equation in temperature and mole fraction. Methods for predicting ternary excess volumes from the V(E)s of the three binary mixtures involved are examined and tested for the ternary mixture at T = 303.15 K. Comparison of the predictions with experimental excess volumes and densities at T = 303.15 K are presented by different methods. Some of these methods together with the correlations of the reported binary excess volumes could be used to obtain good estimations of the densities for the ternary mixtures in the range T = 283.15 K to 333.15 K.