Campaigners have called for increased funding to improve the energy efficiency of Scotland's homes as MSPs prepare to debate fuel poverty.

The Existing Homes Alliance, which includes WWF Scotland, Changeworks and the National Insulation Association, wants a commitment for all homes to achieve a minimum energy efficiency rating by 2025.

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Labour will use its parliamentary debating time to call for a new target to eliminate fuel poverty after the Scottish Government failed to meet its pledge to eradicate the problem by November 2016.

The latest figures show about 845,000 households - or 35% of homes in Scotland - are still living in fuel poverty. Almost half of those affected are pensioners.

Speaking on behalf of the alliance, Fabrice Leveque, climate and energy policy officer at WWF Scotland, said: "It's a national shame that there are nearly 850,000 households in Scotland living in fuel poverty, and that energy inefficient homes are preventing many of those from escaping that poverty.

"That's why we're calling on all political parties to support greater investment in energy efficiency measures and end the scourge of cold, damp, unhealthy homes.

"The Scottish Government already has all the powers it needs to improve the quality of the homes we live in, we now need to see a commitment in the draft budget that will lift all homes to the Energy Performance Certificate Band C standard by 2025.

"Investment in energy efficiency is a no-brainer, working alongside efforts to raise incomes and reduce energy costs, it will help lift people out of fuel poverty, stimulate the economy, create jobs and cut our climate change emissions."

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Earlier this month, Housing Minister Kevin Stewart announced an extra £10 million to tackle fuel poverty, defined as households spending 10% of their income on heating.

The Scottish Government has said an independent review of the definition of fuel poverty will be carried out.

Labour's deputy leader Alex Rowley said: "In 2016 nobody should have to face the choice between heating or eating. We live in a modern, wealthy country, yet hundreds of thousands of Scots can't afford to heat their home.

"The fact that 845,000 households in Scotland live in fuel poverty is shameful and should spur every political party into serious action.

"Labour wants to see a Warm Homes Act to drive up standards and regulations along with a measurable plan of action that will show year on year targets for eradicating fuel poverty in Scotland.

"Action speaks louder than words and to date, despite the warm words from the SNP, hundreds of thousands of adults and children remain in cold, damp and unacceptable housing conditions.

"I challenge the other political parties to back Labour's call for a new fuel poverty target to be set, so that once and for all we can tackle this issue."

The Greens will use the debate to propose a series of measures including a minimum energy efficiency rating for homes, street-by-street retrofitting and extra support for home owners to carry out repair work.

The party's housing spokesman Andy Wightman will argue fuel poverty should be treated as a welfare problem.

He said: "Those living in a fuel-poor home face higher risks of poor health and lower educational attainment, as well as the added stress of having to make difficult choices between heating and putting food on the table or buying a new school uniform.

"The SNP must increase funding in the Scottish budget for 2016-17, as part of a progressive long-term increasing of the fuel poverty-energy efficiency budget."

READ MORE: Number of winter deaths down to just over 20,500

Kevin Stewart, minister for local government and housing, said: "We remain absolutely committed to tackling fuel poverty in Scotland. This debate is a welcome opportunity to raise the profile of this important issue and work constructively as a Parliament to make clear our priority is that everyone should have a warm home.

"It was this Government that set up the Fuel Poverty Strategic Working Group and the Rural Fuel Poverty Task Force - to deliver our commitment to introduce a Warm Homes Bill to tackle fuel poverty.

"We will now work to bring this forward, while taking into careful consideration the over 100 complex recommendations from the both of these groups' reports and a new effective eradication strategy to be published in 2017."