Three things: insulation level, electrics, and how much you can change.
Both are insulated, and that is what separates a pod from a garden building. A garden pod uses a high-specification foil insulation system in the walls, roof and floor, which is enough to make it comfortable through a British winter. A garden room steps up to a fuller specification again.
Electrics is the bigger difference. A garden room includes them as standard. A pod does not.
Finishes are the third. A garden pod has a good, straightforward specification and you choose your cladding and where the doors and windows go. A garden room opens up far more choice on glazing, doors, internal finishes and extras.
Price follows all of it. Garden pods start at £6,976 and garden rooms at £9,321. Both are 8 × 6ft buildings in their standard specification, each with its cheapest door, and the garden room price includes the electrics a pod adds as an upgrade. A pod also tops out at 200 square feet where a garden room reaches 420. For a lot of people a pod does everything they actually needed.
What is not different is who builds it. Same workshop, same panels, same installers, same ten-year structural guarantee. You are not buying a lesser building, you are buying a smaller specification.
Compare the Garden Rooms range