Insulation

4 clues
Fuel saver
Stuff in the attic
Attic covering, maybe
Energy-saving material
Similar answers:
Abbreviation
Abbreviations
Aberration
Aberrations
Abjuration
Ablation
Abomination
Acceleration
Accreditation
Accumulation
Accusation
Accusations
Acestationzebra
Acmecorporation
Acrossthenation
Activation
Activations
Actofabdication
Adaptation
Addinsulttoinjury