Three softwood species, spruce (Picea abies Karst.), fir (Abies alba Mill.), and larch (Larix decidua Mill.), and five hardwood species, oak (Quercus petraea Liebl.), ash (Fraxinus excelsior L.), beech (Fagus sylvatica L.), cherry (Prunus avium L.), and black locust (Robinia pseudoacacia L.) were treated at high temperatures under vacuum conditions with Termovuoto® technology. All of the wood species were treated at different temperatures (from 160 to 220°C), different times (from 45 minutes to 5 hours), and under different pressure conditions (160, 210, and 330 mbar). The treated material was characterized in terms of mass loss, color changes, and equilibrium moisture content. Results showed dissimilar behavior of various wood species and their different sensitivities to treatment schedules. Consequently, the series of tests performed allowed a detailed characterization of the Termovuoto® process and its effect on product quality.