Conservatory vs Extension vs Garden Room

ConservatoryExtensionGarden Room
Typical cost\u00a38k\u201330k\u00a320k\u201360k\u00a38k\u201325k
Build time2\u20134 weeks8\u201316 weeks1\u20133 weeks
PlanningUsually not neededUsually neededUsually not needed
Year-round useCold in winter, hot in summerYes \u2014 fully insulatedDepends on insulation
Adds property value?Modest (5\u20137%)Significant (10\u201315%)Modest (3\u20135%)