Asked to picture a 20th-century interior, the under-30s may conjure up an IKEA catalogue while those a little older might opt for Habitat. However, as the new extension of the Geffrye Museum shows, interest in modern interiors goes back to the beginning of the century.

The Geffrye Museum was established in 1914 in Hackney, at that time the centre of London’s furniture trade, in the grounds of former alms houses of the Ironmongers’ Company. This was at the behest of the Arts and Crafts movement to educate the local population in furniture and woodwork.

After being taken over by London County Council in 1935, the museum was reorganised to show the history of domestic life. Until December last year, it specialised in period living rooms, tracing styles and tastes from the l600s to the end of the 19th century. The rooms reflected the changing social and economic priorities of the urban middle classes through the interiors of their homes.

The philosophy, according to deputy director and head of education Christina Lalumia, is not to show a random selection of historical objects but to recreate how a particular individual lived. Each room evokes an imaginary occupant: “We’re not just looking at decorative trends but who was buying what and why, and how they might have put the pieces together. We are not about objects in themselves, but the relationships people have with them. All our rooms are contextual, so it matters who used them. They are meant to be snapshots in time.”

The aim is to illustrate defining movements in living patterns. “It involves painstaking research, especially for our 20-century rooms,” say Ms Lalumia. “We looked at how land was used, where and how it was developed. We had to define new building types in London down the century and pull out new and meaningful styles that had a future influence.”

A measure of their success is that elements from all four of the room sets representing the 20 century are still commonplace. You feel that you could walk into any of them.

The Edwardian drawing room in a Golders Green house built after the Tube had breached Hampstead Heath reflects the new ideal of light sunny rooms with large French windows leading out to the garden, popular with the middle classes in the first part of the century. Sunlight and fresh air were key elements in the new emphasis on health and hygiene in the home. A large removable rug, for example, replaced the “unhygienic” fitted carpet. The room was less cluttered than in Victorian times with simple furniture reflecting Art and Craft style. The focus of the room is the plain wood-surround tiled fireplace.

In the 1930s the fireplace remains the focal point, despite central heating, but is replaced by an electric fire surrounded in green marble. This set, combining a living and dining room, reflects the move to fashionable apartment blocks, especially by the surprisingly numerous childless professional couples. The flats, although small, offered all the latest conveniences, including electricity, telephones, constant hot water and central heating and, in the most upmarket developments, facilities such as shops, hairdressers, swimming pool and even a ballroom.

The Geffrye flat has a simple Modernist interior: a large plain easy chair, a bold geometric patterned rug, low shelves with a few carefully chosen objects including a state of the art gramophone, wireless and bakelite phone. The dining table, by Gordon Russell, is tucked into the recess of the large curved window giving on to a balcony.

The 1950s room also leads out on to the patio with Ernest Race Antelope chairs in bright colours to rival the plants. The small town house on a Span estate illustrates that space is at a premium.

Open-plan living areas replace small separate rooms. The stairs rise directly from the living room removing the need for a separate hall, possible only with the advent of central heating. The walls are white, with Scandinavian-style open-framed teak furniture on spindly legs which could easily be placed against the large windows without blocking the light.

A bright abstract rug partially covers the easy-to-clean wood-block floor. There is no fireplace; the focal point of the room is now the television.

The television remains in the “loft space” set of the 1990s. Today’s domestic interior is yesterday’s industrial space. It is minimalist, with living, cooking and eating area in one, the furniture and artefacts echoing many of the shapes and style details of the 1950s room. The emphasis is on space and light, where a lot is spent on the least.

Trying to be objective about contemporary culture was difficult for the curators, says Christine Lalumia. “One of our main worries was that if we choose objects from our own time, would we be making them more significant than they really are? And are we just including our own taste?” To avoid this the curators consulted major design and retail stores as well as interviewing loft dwellers about their purchasing patterns.

The Geffrye has always had a clear educational remit: “The education rooms are in the best position in the new building and it is no accident that they are designed to be absolutely visible,” says Ms Lalumia. The dramatic horseshoe plan on two levels with a low undulating steel and glass roof connecting to the original buildings stretches out like a dragonfly’s wings. Alongside the purpose-built teaching areas is the Geffrye Design Centre, devoted to the many designers and craft-makers practising in Hackney. It has an interactive data base, exhibition space and offers workshops.

In the past the museum has been well known for its work with primary pupils but its extension allows more secondary provision, for example in history GCSE components such as Britain between the Wars, and in design and technology, especially on the cultural components at A-level. Pupils will find it an enjoyable and worthwhile visit - and you might even get some ideas for home sweet home.

Geffrye Museum, Kingsland Road, Shoreditch E2 8EA. Tel: 0171 739 9893. Free.