Installing “green” energy saving measures in the home is so expensive it can take more than 200 years to cover the cost.

Solar panels are one of the least cost effective upgrades, according to the Royal Institution of Chartered Surveyors (Rics), which today published The Greener Homes Price Guide.

The cost of adding solar panels to the average home is between £4,000 and £5,000, but the energy savings are worth as little as £24 a year, according to Rics, meaning it would take about 208 years to pay back the price of installation.

The report also reveals that the average cost of replacing a wall-mounted boiler with a more energy-efficient version is about £1,700. But with expected savings of just £95 a year, it would take up to 18 years to offset the cost.

The most cost effective energy saving measure is cavity wall insulation. At a cost of between £440 and £2,400, depending on the size of the home, and an average energy savings of as much as £145 a year, the cost could be paid back over as little as three years.

Joe Martin, director, of Rics’s Building Cost Information Service, said: “We all have a role to play in helping to reduce our carbon footprint, be it through changes to our behaviour or by choosing greener alternatives. The reality is, however, that most people struggle with the cost, time, and effort it takes to make these changes.

“The Greener Homes Price Guide gives consumers a comprehensive heads-up about the costs and effectiveness of green upgrades, whilst protecting them from being duped into changes that won’t save them money or do little to reduce their carbon footprint.”

However, the solar panel industry vigoursly denied the claims. Andrew Lee, head of solar at Sharp Electronics, said. “Rics's claim on solar panels is massively misleading and potentially damaging for both the UK solar industry and the UK’s renewable energy targets, being based on outdated and inaccurate information. Instead of 50 years plus for payback, most average installations will payback within approximately 12-15 years.

“Solar power works, it’s long term and effective – and it’s more than adequate to meet the UK’s energy demands. What’s more, once installed, solar power is free – and super-green - it can even add up to 10 per cent to the value of your home.”

Less than 100,000 properties in the UK have some form of microgeneration system, such as solar panels, wind turbines and heat pumps. In contrast, German householders installed more than 75,000 solar generation systems alone in 2006. In Germany, the Government pays people to generate their own electricity, which is fed into the National Grid.

The research by Rics follows an investigation by Times Money which discovered that wind turbines are rarely cost effective.

A large free-standing wind generator can cost anything from £12,000 to £24,000 to install. But they are only really economic or practical for people in rural areas, particularly those not connected to the electricity grid. Even then, and taking account of electricity fed back into the grid, it would take at least 15 years for them to pay for themselves.

The same goes for ground-source heat pumps. They take natural heat from the ground and boost it to useable levels using a small amount of external electricity.

The Energy Savings Trust, a government-backed group that promotes better energy use, says that a six-kilowatt ground-source heat pump will cost up to £10,000 to install and save as much as £750 a year in energy costs. But heat pumps work best with under floor heating, which can cost a further £20,000 to install.