More than half of Devon homes deemed eligible for new energy-saving measures under a government grant scheme have had them installed, new figures show.
The Green Homes Grant scheme saw the Government pledge millions to low-energy efficiency or low-income households, to allow them to make energy-saving changes to their homes.
Friends of the Earth welcomed the scheme but warned its progress has been "patchy and unequal".
Some £500 million was available across the first two phases of the scheme, with the first administered by local authorities after submissions were open between 2020 and 2022.
Now, new figures from the Department for Net Zero and Energy Security show 52 households in Devon were approved for upgrades during the first phase of the scheme.
To qualify, households could be identified by the local authority or apply directly for a grant.
As of August, 32 separate measures had been installed in 28 Devon homes.
Across England, some 27,387 homes were signed up to the scheme, with 23,821 individual measures installed across 18,528 (69%) of them.
Rosie Downes, head of campaigns at Friends of the Earth, said: "Upgrading the UK's poorly insulated housing stock is one of the quickest and most effective ways to cut carbon and reduce bills.
"While thousands of eligible homes have been upgraded under the scheme, delivery is patchy and unequal.
"The climate emergency and cost-of-living crisis mean we need a robust national plan to roll out energy efficiency upgrades consistently and fairly.
"This requires proper investment to make sure every home is warmer, cheaper to run and low-carbon."
The measures funded by the scheme include wall, loft and roof insulation, improvements to windows and doors, installing solar panels and fitting heat pumps.
The upgrades in Devon included 17 solar panel deployments and 10 loft insulation installations.
Simon Francis, coordinator of the End Fuel Poverty Coalition, said every home upgraded was a "step in the right direction", but warned progress should "be delivered at speed and with the urgency the energy bills crisis deserves".
He added: "Every winter spent in a cold damp home causes misery and health complications for millions of households.
"This is why the Government's Warm Homes Plan must be rooted in a "warmth first" principle, treating a warm, dry and affordable-to-heat home as a basic human right.
"And upgrades to homes must come alongside reform to electricity pricing and moves to secure our energy supply in the future."
A DESNZ spokesperson said: "The energy shocks of recent years have shown the urgent need to upgrade British homes.
"Our Warm Homes Plan will make them cheaper and cleaner to run, rolling out measures from new insulation to solar and heat pumps.
"We are investing £13.2 billion to improve up to five million homes over this Parliament, helping families to cut their energy bills for good."