Generally yes, demolishing a habitable house is development requiring planning permission unless it falls within limited exemptions, such as demolition ordered by a local authority for safety reasons or as part of an already-permitted redevelopment scheme. Demolition of a protected structure or a structure in an Architectural Conservation Area is very unlikely to be exempt and normally needs both planning permission and, where relevant, prior consultation with the conservation officer.
Under the Planning and Development Act 2000, the demolition of most structures is treated as 'development' and, in the case of a habitable house, generally requires planning permission from the local authority. This applies whether you intend to rebuild on the same footprint, redevelop the site for something else, or simply clear the land. The rules exist partly because demolition removes the housing stock and can affect the character of a streetscape or area, so local authorities want the opportunity to assess proposals rather than have buildings disappear without oversight.
There are limited exemptions under the Planning and Development Regulations 2001 (as amended), Schedule 2, mainly covering demolition works that are part of development already granted permission, certain minor works, or emergency demolition directed by the local authority under dangerous structure powers where a building poses an immediate risk to public safety. Outside of these narrow categories, demolishing an intact, habitable dwelling without permission is unauthorised development and can expose the owner to enforcement action.
If the house is a protected structure, listed on the Record of Protected Structures, or located within an Architectural Conservation Area, the position is stricter again: demolition is very rarely exempt and will usually require full planning permission, with the local authority's conservation officer likely to object to demolition unless the structure is genuinely beyond repair and alternatives have been ruled out. Given the consequences of getting this wrong, it's best to confirm the exact position with the planning authority before any demolition work begins.