If you are a person that is concerned with the effect on the environment of producing goods for an ever demanding population, or are worried about the amount of rubbish that we are creating for landfill, there is no better way of being responsibly 'green' than by using an attractive antique piece for a key position rather than a flatpack from a Swedish company.
In the antiques trade one of the most repeated phrases we hear is 'I love that piece but I live in a modern house'. If your house was built in 2015 or 1615 the space you create is yours to be an individual, and using a piece such as an antique pier table in the hall or a small Victorian mirror in the downstairs cloakroom will add an interesting feature that guests will comment on, rather than not even notice, as well as the possibility of gaining value rather than ending up in the local tip in a few years.
If you are furnishing with antique pieces it doesn't mean that you have to live in a museum. A modern simple sofa in the middle of a sitting room suddenly gains elegance when a pair of small antique side tables are placed at either end, maybe finishing the effect with a pair of re-wired Edwardian brass lamps. Or in the guest room use a painted 19th French window seat at the end of a bed, both practical and interesting.
I have been in a house built in the 1960's that had one of those open tread staircases popular at the time, this was complemented by a collection of antique glass pictures, and when you reached the landing it was very simply furnished with an 18th century walnut 'fret' framed mirror. The whole effect was interesting and welcoming, the arrangement complemented the modernity without fighting with it.
Original Art Deco furniture is still very desirable and will blend well with simple modern items, In his town house in London Elton John furnished with Art Deco combined with early 19th century continental 'Biedermeier' pieces in blond wood. The designs blending well with the walnut tones of Deco. He also commissioned modern pieces designed by David Linley, the whole effect was elegant comfortable and harmonious.
Whatever your taste there is always an antique piece that will complement and add interest to a scheme, as well as being 'green' and potentially a good investment.