Due to increasing environmental concerns, significant attention has been gained for seeking out alternative sources for deforestation and to reduce as much as possible for the utilization of petroleum-based chemicals. In the present work hybrid bio-composites have been developed using epoxy resins (DGEBA-isophoronediamine and DGEBA-phenalkamine) and hybridized blend of bio-based cardanol-diaminodiphenylmethane (C-ddm) benzoxazine and DGEBA-isophoronediamine (bio-benzoxazine: epoxy resin 50:50 wt%)reinforced with desert cotton (DC) and areca nut husk fibres (ANF) separately under appropriate experimental conditions, in order to utilize them for high performance thermal, electrical and acoustic insulation panel applications. Mechanical behaviour, thermal conductivity, thermal resistance, electrical surface resistivity, electrical volume resistivity, sound absorption coefficient and sound transmission loss were studied as per standard methods. Results obtained from different studies infer that hybrid blended cardanol benzoxazine composite panels reinforced with desert cotton sandwich areca nut husk fibre (DC-sw-ANHF) possess appreciable thermal resistivity and electrical volume resistivity and the corresponding values are 0.22141 M2 k/w, and 1.888 × 1010 Ω, respectively. Data obtained from acoustic studies, indicate that all the fibre reinforced composites possess more than 0.7 value of sound absorption coefficient at 6400 Hz. The composite panel specimens developed using both desert cotton, and areca nut husk fibre reinforced with hybridized blend of bio-benzoxazine/epoxy resin can be used as insulation materials in the field of building construction.