What is a better word for renovation?

There's no single better word for renovation, only more precise ones, and which you pick depends on what you're emphasising. Renovation is the broad term for improving an existing building. The alternatives each narrow it down.

Refurbishment points at finishes and fittings: new kitchen, new bathroom, redecoration, flooring, all without major structural change. Restoration means bringing original features back, so on a Victorian terrace that's repairing cornices, stripping paint off a staircase, or having sash windows rebuilt rather than replaced. Remodelling is about layout. When we take down the wall between a kitchen and rear reception in an Edwardian semi, that's remodelling, even though most clients would just call it renovating. Retrofit is the energy word: insulation, airtightness, new heating, better windows.

The practical way to pick is to name the work by its main purpose. Updating a tired ex-rental flat is a refurbishment. Reinstating period detail is restoration. Moving walls makes it a remodel, and cutting heating bills makes it a retrofit. If a project mixes all four, which most whole-house jobs do, renovation is still the honest umbrella word. How renovation differs from refurbishment in the strict sense is a separate question. For quotes and planning conversations, though, precision pays. Ask a builder to price 'a renovation' and you'll get a vague answer. Describe a remodel or a retrofit and the quote gets sharper.