When Simon Duffy gets another energy bill, his heart sinks. “It’s madly expensive,” he says.

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

Despite being someone who cares about climate change, and keen to retrofit his property to make it more efficient, there’s a problem.

“The whole question of how to better insulate the house is a real mystery to me,” says Mr Duffy, a director of sustainability think-tank Citizen Network. “I don’t know where the expertise for that is.” He also adds that he’s also not sure whether he could install solar panels, given that he lives in a conservation area.

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

Around 29 million British homes require retrofitting by 2050, according to the UK Green Building Council, an industry body.

Retrofitting might involve measures such as improving your home’s insulation, upgrading the heating system, or installing energy-generating devices such as solar panels, or even a private wind turbine.

These adjustments can cost thousands of pounds up front, but, if properly executed, they could improve comfort and reduce people’s bills in the long-run.

Plus, increased energy efficiency ought to cut carbon emissions from homes, especially if property owners switch away from gas or oil-fired boilers, for example.

Roughly one fifth of the UK’s total emissions comes from residential buildings.

Amy Peace and her husband live in the northwest of England, near Warrington. The pair both work in sustainability, advising businesses on their path to net zero.

They were keen to improve the quality of their home and apply the principles they promote at work to their own lives – but they too faced challenges when deciding on how to go about it.

“Even though we’ve got this background, and we’re engineers as well, what we weren’t entirely clear on was where was best to spend the money,” says Mrs Peace.

The couple spoke to multiple consultants, but Mrs Peace found the advice they received was often geared towards meeting Passivhaus standards – an ultra-energy efficient type of building.

“There weren’t many in that pragmatic middle space where you are literally saying, ‘We’ve got this much money, where would we be best putting it?’,” Mrs Peace adds.

Perseverance during the past three years paid off, however, and the couple’s 1930’s detached house now has improved insulation, a heat pump, and an electric car charging point. Solar panels and battery will follow shortly, if all goes to plan.

Conscious of the confusion around approaches to retrofit, some organisations are moving to improve the advice available to homeowners. Among them is Ecofurb.

“We can model all the different options that are available, suitable for your home and your budget, and identify a package of measures,” says Liz Lainé, of Parity Projects, a housing data analysis company, which runs Ecofurb.

The firm offers this initial consultation for free, but full plans, with personalised input from a retrofit coordinator, start at £470. Ecofurb can also oversee any works as they are carried out by contractors to avoid “horror stories”, says Ms Lainé.

There are many other organisations that offer to help homeowners plan a retrofit.

The work often involves carrying out a heat-loss survey, to spot cold areas that require insulation, and to better understand a property’s heating demand. Experts might also advise on the suitability of solar panels for your home, for example.

There’s the Get a Heat Pump website, launched by the charities Nesta and The MCS Foundation, which explains what heat pumps are and how they might fit into a home renovation plan.

RICS, the Royal Institution of Chartered Surveyors, has also just launched a new retrofit standard for its members – essentially, it encourages surveyors with the appropriate training to offer their services to homeowners planning or undergoing a retrofit.

The RICS website will soon include a range of retrofit advice and a tool to help homeowners find a suitable surveyor in their local area, says Steve Lees, from the RICS retrofit project team.

Improving the energy efficiency of homes is “essential” for decarbonisation, says Gerald Charles, head of housing retrofit at the Centre for Sustainable Energy, but he adds that the current lack of good advice remains a genuine problem.

“The industry as a whole don’t appreciate the importance of good retrofit advice,” he says.

One entrepreneur who has noticed a knowledge gap in the market is James Major, founder and chief executive of HubbPro, which helps architects plan energy efficient buildings. Architects don’t always have the latest information about how to incorporate energy-saving technologies into their designs, notes Mr Major.

“Clean tech isn’t part of what they do or what they should know – that’s an engineering function,” he says. And yet architects’ clients increasingly ask about such tech when planning a new home or an extension.

Through an initiative called MyHubb, Mr Major is now offering architects detailed reports that estimate the carbon reduction potential and payback period on retrofitted measures – such as heat pump-based heating systems or solar panels, for instance.

He says these reports cost around £1,000, though he adds that this price is not yet finalised.

Mr Duffy says he will keep looking for solutions to his own retrofit conundrum. But he makes another point. So much of the currently available technology and advice is tailored to individual homeowners.

He suggests that neighbourhood-scale schemes, for example to provide solar power to a whole street, might make more sense and could include more people in one go.

“That’s what I would think is the logical way of thinking about this,” he says.