Conservatory vs Extension vs Garden Room

ConservatoryExtensionGarden Room
Typical cost£8k-30k£20k-60k£8k-25k
Build time2-4 weeks8-16 weeks1-3 weeks
PlanningUsually not neededUsually neededUsually not needed
Year-round useCold in winter, hot in summerYes - fully insulatedDepends on insulation
Adds property value?Modest (5-7%)Significant (10-15%)Modest (3-5%)