The study of deployable buildings, together with their technical systems and energy sources, is driven by the urgent need for effective mobile shelters for military personnel and internally displaced persons in war-affected areas and humanitarian crises. The primary object of the research is a modular pneumatic tent structure integrated with an autonomous “energy block” containing HVAC systems and a PV with storage installation. The methodology combines instrumental testing of relevant material properties, hygrothermal calculations, and dynamic energy modelling in climatic conditions of Ukraine. The first stage of the research focuses on the experimental investigation of a small-scale prototype of a modular pneumatic tent structure in a climatic chamber, as well as on testing the thermal insulation and vapour permeability properties of tent materials at Riga Technical University. For the four different samples of additional insulation tested for tent applications, thermal resistance ranged from 0.163 to 0.562 m²·K/W, while water vapour resistance ranged from 17.75 to 74.67 Pa·m²/W. Because insulation in tent structures is applied to the internal surface of the walls, interstitial condensation may become a significant issue during the winter period. Hygrothermal calculations showed that significant interstitial condensation risk was identified without a vapour barrier. The results were derived for blended cotton and hemp-fibre insulation, with the latter showing a lower risk of interstitial condensation. For the configuration including an internal vapour barrier, the simulations indicated that moisture condensation was practically eliminated. Energy demand models were used to assess the impact of different design configurations and operating modes. The results showed that increasing the insulation thickness for from 2−20 mm can substantially reduce heating demand. In addition, the application of adaptive or intermittent HVAC control schedules can deliver a further 25–40% reduction in energy demand. Energy modelling confirms that system configuration strongly affects both energy use and self-sufficiency. The air-to-air heat pump performed best, with the lowest annual consumption (3,500 kWh) and only 54% grid dependence. The solid-fuel heater offered the highest self-sufficiency (27.5% grid electricity) but at much higher total energy use. A 3.66 kWp PV system with 10.64 kWh storage partially covered demand but did not achieve full energy autonomy.