It features a whole roof of solar panels, an artesian water well and a few Gripples in its construction.
The Facey family’s new home stands in stark contrast to Clifford House, the Victorian mansion they have just moved out of across the lawn.
Mulberry House was a grand design which the family were involved in every step of the way. It is so green it has no need of a gas supply and with water flowing naturally up a borehole from rock strata 180ft down, it can go completely off grid.
Gripples are small lozenge-shaped wire joining devices which have made Hugh Facey a fortune. They revolutionised the fencing industry and have gone on to be used for suspending everything from electricity cables to air ducts - their use in Mulberry House.
The four-bed home also has huge floor-to-ceiling windows and is mostly built on one level - apart from the terraces.
Mr Facey said: “I have no plans to retire. The thing I find frustrating in Sheffield is the loss of the big, well-known family businesses. It’s really sad. I’m trying to build something that will last forever.”
The company is famous for being innovative and fair and successful.
In the last period, one eighth of the year, it turned over £7million for the first time and made £1m profit.
Mr Facey is a champion of employee-ownership and pays workers a £20,000 minimum. It also pays into a non-contributory pension and offers life and private health cover.
The firm, which employs 500 - including 100 in Chicago, 100 in Europe and 20 in India - had its best year ever in 2015 when it just missed a £50million turnover.