Do houses need lightning protection?

Lightning rods are common on houses in parts of the United States, which is where much of what you read online comes from. In the UK, very few homes have one, and for most that is the right answer. But there are exceptions, and there is a related protection that most homes should consider.

Why most UK houses do not need one

Whether a building needs lightning protection is decided by a risk assessment under BS EN 62305-2. It weighs how likely the building is to be struck, from its size, height and surroundings and how often thunderstorms occur locally, against what a strike would cost in lives, heritage and money.

For a typical two-storey house in a street of similar houses, the chance of a direct strike in any one year is very low. The surrounding houses, trees and buildings share the exposure. The assessment usually comes out below the level where protection is needed.

When a house might need it

The picture changes for homes that stand out:

Historic England recommends that lightning protection is considered for tall or prominent historic buildings. Insurers of thatched and listed homes may also ask about it.

What a house system involves

The same parts as any other building, on a smaller scale: an air terminal or ridge conductor on the roof, one or two down conductors on the outside walls, and earth rods at the bottom of each. It is designed to BS EN 62305 and should be installed by a specialist. Once fitted, it needs inspecting and testing like any other system. Published UK prices for testing a house or small building run from about £200 to £350 excluding VAT.

A badly fitted system, or one that has been damaged and not repaired, can be worse than none, so do not fit a rod without the earths and testing that go with it.

Surge protection: the protection most homes need

A direct strike is rare. A strike nearby is much more common, and it can still do damage. The strike induces a voltage spike in overhead lines, underground cables and phone lines, which travels into the house and through anything plugged in.

Surge protection devices fitted in the consumer unit divert that spike to earth. The wiring regulations, BS 7671, now expect protection against transient overvoltages in most new and altered installations, so many homes get one when the consumer unit is replaced. Published prices are around £120 to £180 fitted for a Type 2 device, or £250 to £400 for a combined Type 1 and 2 where the supply comes in overhead. See our page on surge protection for how the types differ.

Does home insurance cover lightning?

Most UK buildings and contents policies cover damage caused by lightning, including fire from a strike and, often, electrical damage from a surge. Policies vary on what they class as lightning damage rather than a general electrical fault, and some exclude damage to equipment unless there is evidence of a strike nearby. It is worth checking the wording on your own policy, particularly for expensive equipment such as home offices, heat pumps, solar inverters and electric vehicle chargers.

Insurers of thatched, listed and high-value homes sometimes ask whether the property has lightning protection, and may ask for a current test certificate if it does. If you are told a system is needed, ask what standard and class they expect, and get it in writing before you commission the work.

Solar panels and heat pumps

Rooftop solar does not by itself make a strike more likely, but it adds metal and cables on the roof and electronics inside. If the house already has a lightning protection system, the array should be kept a safe distance from it or bonded to it, as the designer decides. If it does not, surge protection on the solar circuit and at the consumer unit is the usual answer.

What to do if you are unsure

• If you live in an ordinary house, ask an electrician about surge protection next time the electrics are worked on.
• If your home is tall, isolated, thatched or listed, ask a lightning protection specialist for a risk assessment before deciding.
• If the house already has an old conductor, have it tested; a neglected system should be repaired or removed, not ignored.

For anything larger than a house, such as a school, church or commercial building, the lightning protection contractors homepage explains the options. To get a specialist to look at your property, use the form below.