California is poised to become the first state to require solar panels on virtually every home under a newly passed rule.

The building standard approved by the California Energy Commission would mandate the existence of solar arrays on new single-family residences and on multi-family buildings of up to three stories.

Commissioners unanimously passed the proposal, saying it would bolster the state’s efforts to combat climate change and help California accomplish its energy reduction goals.

“We cannot let Californians be in homes that are essentially the residential equivalent of gas guzzlers”, said commissioner David Hochschild, who hailed the change - which takes effect in 2020 - as a “very bold and visionary step”.

The state is working towards cutting emissions to their 1990 levels by 2020 and has a goal of making all new homes “net energy zero” by 2020 - in other words, ensuring they do not consume more than they produce.

The measure seeks to help California get there, but it will also add to housing costs in a state that is already facing a dire shortage and soaring real estate prices. An official analysis found that the solar mandate would add about $9,500 to the price of building a single-family residential home.

Solar Technology in the UK Show all 7 1 /7 Solar Technology in the UK Solar Technology in the UK Roofs tiled with photovoltaic solar energy panels receive maximum sunlight exposure in Dyfi Eco Park, Machynlleth, Wales. These panels are made up of photovoltaic (PV) cells. PV cells convert sunlight into electrical energy Getty Solar Technology in the UK Jake Beautyman installs solar panels on a barn roof on Grange farm, near Balcombe. The installation is part of an initiative by local residents in Balcombe to encourage more people to use renewable energy rather than energy based on carbon such as fracking. The initaitive is called Repowerbalcombe and is supported by the charity 10:10 Getty Solar Technology in the UK The Solar array of community project Low carbon Gordano, a Solarsense renewable energy project. Delivering 1,750HWh per annum. Avon, Somerset Getty Solar Technology in the UK The solar panels array on the roof of Oldfield Park Infant School, installed with the support of Bath and West Community Energy a community project. Bath, Somerset Getty Solar Technology in the UK The solar array inverters that monitor and invert the energy made by Brixton Energy Solar who have installed several hundred square metres of solar panels on the roof of Elmore House in the Loughborough Estate in Brixton, London Getty Solar Technology in the UK The solar array inverters that monitor and invert the energy on the roof of Elmore House in the Loughborough Estate in Brixton, London Getty Solar Technology in the UK The 25kW solar panel array on the roof of Knowle West Media Centre. Supported by Bristol Energy, a community-owned energy cooperative, growing Greater Bristol's local green energy supply and making the benefits available to all Getty

But those costs would be offset by reductions energy savings, the commission predicted, estimating that the average single-family home would save about $19,000.

Given California’s size - it is America’s most populous state and the world’s 5th-largest economy - its decisions can influence the rest of the country. Robert Raymer of the California Building Industry Association suggested that the state’s “quantum leap in statewide building standards” would ripple outwards.

“You can bet every other of the 49 states will be watching closely to see what happens”, he said.

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The California Building Standards Commission must still approve the change.