Small wind turbines for homes and farms: do they pay back?

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The short version: a home wind turbine only pays on a genuinely windy, open site. Even then, payback is usually 20 years or more. For most homes, solar is the better buy.

Why wind speed is everything

The energy in wind rises with the cube of its speed: double the wind and you get eight times the energy. So a 10% overestimate of your wind speed can overstate generation by around 30%. That's why two sites that look alike on a map can perform very differently.

How windy is Guernsey?

Very, by British Isles standards. Guernsey Airport averages about 6.45 m/s (12.5 knots), blowing hardest in winter, which is handy because that's when you need the most power for heating.

Source: Met Office UK climate averages, Guernsey Airport, 1981–2010, measured at the standard 10 m height (checked 27 Oct 2026). The airport is on an open plateau, so it is more exposed than most gardens.

Treat the airport as the island's best case. Valleys, hedge-lined lanes and St Peter Port's streets will be much calmer. Exposed west- and south-west-facing cliff-tops and coastal fields may be similar or windier.

Costs and typical savings

The Energy Saving Trust (updated 20 May 2026) puts a 6 kW pole-mounted turbine at about £35,000 fitted, saving about £650 a year in GB (about £800 in Northern Ireland). That's over 50 years to pay back. Building-mounted turbines are smaller, typically around 2 kW. There are currently no GB grants for wind turbines.

A strong, open site that uses lots of its own power, like a farm with daytime loads, can do much better. Our calculator, using Guernsey's airport averages, an open site and a 15 m hub, suggests about £1,300 a year after £300 of maintenance. That's still over 20 years at the EST price, before any repairs. Real quotes, turbine choice and measuring your own wind could change this a lot either way.

Why small turbines struggle in towns

• Buildings and trees slow the wind and make it turbulent. Turbines make less in gusty, shifting wind and wear out faster.
• Rooftop turbines sit in the messy air around the building, and vibration and structural loads limit their size.
• UK field trials, including the Warwick Wind Trials and the Energy Saving Trust's 2009 field trial, found many urban and suburban rooftop turbines produced only a small fraction of their predicted output, sometimes less than the power they used themselves.
• The Energy Saving Trust says wind is less suitable for built-up or sheltered areas. For most town houses, solar will be the better buy: see our solar payback guide.

Planning and noise

• Wales and Northern Ireland: planning permission is required (EST).
• England and Scotland: some smaller turbines can be permitted development, but there are strict conditions on size, height and distance from boundaries, and the rules are complex (EST). Check with your council before buying.
• Noise: permitted development relies on the turbine meeting the MCS noise standard (MCS 020) at the nearest neighbour. Turbines close to houses often fail it. Larger farm turbines usually need a full application with a noise assessment.
• Guernsey: contact the Development & Planning Authority before you commit. We haven't confirmed the island's specific rules for domestic turbines.
• Listed buildings, conservation areas, airports and radar can all add restrictions.
• Use an MCS-certified turbine and installer. You need this for export payments in GB.

Before you buy

1. Measure the wind at your site for at least a few months with an anemometer at hub height, or ask installers for a site assessment.
2. Ask for the turbine's certified power curve and annual energy figure at your average wind speed.
3. Get a written price for servicing, insurance and inverter replacement.
4. Compare it with solar on the same budget.

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