Simon Duffy's heart sank when he received another energy bill. "It's ridiculously expensive," he said.

Mr Duffy lives in a traditional stone-walled detached house in Sheffield. He estimates that he spends £3,100 a year on heating and electricity.

Although he was concerned about climate change and was keen to retrofit his property to make it more efficient, there was a problem.

"The whole question of how to better insulate homes is a real mystery to me," said Mr Duffy, director of the Citizens Network, a sustainability think tank. "I don't know where the expertise is for this," he said, adding that he was also unsure if solar panels could be installed, given that he lived on a reserve.

Millions of homeowners across the country may be facing the same dilemma.

Around 29 million UK homes will need renovation by 2050, According to the British Green Building Councilan industry body.

Renovations may involve measures such as improving the insulation of the home, upgrading the heating system or installing electricity generation equipment such as solar panels or even a private wind turbine.

These adjustments can cost thousands of pounds, but if done correctly they can improve comfort and reduce people's bills in the long run.

Additionally, improving energy efficiency should reduce a home's carbon emissions, especially if homeowners no longer use a gas or oil boiler.

Accounts for around a fifth of the UK's total emissions from residential building.

Amy Peace lives with her husband in north-west England, near Warrington. Both are committed to sustainability, advising businesses The road to net zero.

They are passionate about improving the quality of their families and applying the principles they advocate at work to their own lives, but they also face challenges in deciding how to achieve this goal.

“Despite our backgrounds and the fact that we were engineers, we didn’t exactly know where the best money would be spent,” Ms. Pease said.

The couple spoke to a number of consultants, but Mrs Pease found that the advice they received was usually to meet Passivhaus standards - an ultra-energy-efficient building type.

"There aren't many people in that pragmatic middle space who are actually saying, 'We have all this money, where would we better put it?'" Ms. Pease added.

However, persistence over the past three years has paid off and the couple's 1930 detached house now has improved insulation, a heat pump and electric car charging points. If all goes according to plan, solar panels and batteries could be available soon.

Recognizing the confusion surrounding remodeling methods, some organizations are working to improve the advice provided to homeowners. These include Ecofurb.

“We can model all the different options available that suit your home and budget and identify a package,” says Liz Lainé of Parity Projects. Parity Projects is a housing data analytics company that operates Ecofurb.

The company offers an initial consultation free of charge, but full plans with personalized input from a renovation coordinator start from £470. Ecofurb can also oversee any works carried out by contractors to avoid "horror stories", Ms Lane said.

There are many other organizations that can help homeowners plan their renovations.

This work often involves conducting heat loss surveys to identify cold areas that require insulation and to better understand the heating needs of the home. An expert may also provide advice on whether solar panels are suitable for your home, for example.

Some are Get Heat Pump Websitelaunched by charity Nesta and the MCS Foundation, explains what heat pumps are and how they fit into home renovation plans.

The Royal Institution of Chartered Surveyors (RICS) has also just launched new retrofit standards for its members – essentially encouraging surveyors with appropriate training to provide services to homeowners who are planning or undergoing retrofits.

Steve Lees from RICS's retrofit project team said the RICS website will soon provide a range of retrofit advice and tools to help homeowners find the right surveyor in their local area.

Gerald Charles, head of housing renovation at the Center for Sustainable Energy, said improving home energy efficiency was "vital" to decarbonisation, but added that a lack of good advice was still a real problem.

“The industry as a whole doesn’t realize the importance of good retrofit advice,” he said.

One entrepreneur who noticed a knowledge gap in the market was James Major, founder and CEO of HubbPro, a company that helps architects plan energy-efficient buildings. Mr. Major noted that architects do not always have the latest information on how to incorporate energy-saving technologies into their designs.

"Clean technology is not part of what they do or what they should know - it's an engineering function," he said. However, architects' clients are increasingly asking about such technologies when planning new homes or extensions.

Through a scheme called MyHubb, Mr Major now provides architects with detailed reports estimating the carbon reduction potential and payback period of retrofit measures such as heat pump-based heating systems or solar panels.

He said the reports would cost around £1,000, although he added that the price had not yet been finalised.

Mr Duffy said he would continue to look for solutions to his retrofit woes. But he made another point. Many of the techniques and advice currently available are tailored to the individual homeowner.

He suggested that community-scale schemes, such as solarizing entire streets, might make more sense and benefit more people at once.

"I think that's the logical way to think about it," he said.