How Much Does it Cost to Install a Velux Roof Window or a Sun Tunnel?

Would you like more natural light in your home? This page is all about roof windows and sun tunnels, the difference between the two, which one is best and how much they cost to install, including DIY and professional installer prices.

As a bonus, we can also point you in the right direction so you can get a competitive quote for installing one.

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What is a Sun Tunnel?

A sun tunnel consists of a window or dome on the roof and a tube that allows light to enter the house through the ceiling.

velux sun tunnel

Sun tunnel manufactured by Velux

These tunnels have several different names but they are all very similar:

  • Sun tunnel
  • Light tunnel
  • Sunlight tunnel
  • Sky tunnels
  • Sun tubes
  • Sky tubes

The tube that connects the ceiling light to the roof can be flexible or rigid and will be made of reflective material such as foil.

As a general rule of thumb, the shorter the tube, the better as more light will come through.

Rigid straight tubes also transfer more light than flexible ones that have ridges, bends and angles that reflect some of the light back out to the roof.

What is a Roof Window?

Roof windows come in several different flavours:

  • Non-opening windows
  • Opening windows
  • Domes (opening and non-opening)

Dome With Opener:

Image source: Loft Shop

Fixed Non-Opening Dome:

Image source: Keylite

Window For Pitched Roofs:

Which One is Best?

Opening windows are almost always preferable to fixed non-opening versions, although they cost more to purchase.

Don’t forget that windows allow sunlight into the room, this causes the temperature to rise, so ventilation in the form of an opening window is ideal.

Many popular roof windows can be opened manually by hand while some can be opened by installing an electrical switch, which obviously costs more.

Velux-style windows for pitched roofs are often found in loft conversions, domes are frequently seen on flat roofs while sun tunnels are used to transfer light from a roof, through a loft space and into the home below.

How Much Light Do You Get Through a Sun Tunnel or Window?

Domes and windows allow a lot of light into the room and consideration should be given to blinds that can limit the amount of direct bright light through.

Sun tunnels don’t have an off switch, neither can a blind or curtains be fitted to limit the light coming through. They are therefore great for communal areas such as dark hallways, kitchens and even living rooms but shouldn’t be installed in bedrooms.

Several sun tunnel manufacturers claim their products are equal to a 200watt light bulb. In our experience, however, most sun tunnels generate around 100-150watts of comparable light on a good bright day and 50-75 watts on a cloudy day.

How Much Does it Cost to Install a Velux Window or Sun Tunnel?

Sun Tunnels

A typical sun tunnel costs between £275 – £375 for all the parts needed. The distance between the roof tiles and the ceiling will affect the cost, tunnels that require a longer tube will cost more.

The labour fee for the installation is usually between £300 – £500, your location and the size and type of company you choose will affect the labour cost.

Because your installer will need to access the outside of your roof to fit the sun tunnel, complex, high and difficult to access roofs may require scaffolding, this will add extra cost to the project, see how much scaffolding costs here.

Not every home will need to be scaffolded as many roofing firms own equipment, such as roof ladders and access towers etc that could be used to gain access to the roof safely and without additional cost to the customer. Our guide to scaffold alternatives is a great read.

Roof Windows

Roof windows cost more than sun tunnels but they allow much more light into the room and you have the option of openers that let in fresh air too.

Replacing an existing window with one of the same size is cheaper than cutting open the roof and installing one for the first time or fitting a larger window.

Small Velux windows cost around £300 off the shelf plus the flashing kits and sundries at £100. To replace an existing window, expect the work to take 2 men no more than half a day and probably less. Expect the total cost to be between £650-£850.

For larger windows, a replacement will cost between £1200 and £1600 depending on the size of the window.

All the prices above assume that scaffolding isn’t required. If it is, you’ll need to add that to the overall cost.

Installing a new window for the first time or enlarging the existing window space involves additional work such as:

  • Planning the location
  • Cutting the roof timbers
  • Supporting the existing roof timbers to prevent sag
  • Plastering on the inside of the ceiling
  • Painting and decorating the inside

For small roof windows in a new location, expect to pay £900 – £1300 each.

For larger windows, expect to pay £1500 – £2500 depending on size and location.

Don’t forget; the cost of scaffolding isn’t included in these prices but it may not be needed.

Can Tunnels and Windows be Fitted DIY?

The most difficult aspect of fitting a tunnel or window is gaining safe access to the roof.

The process of fitting a sun tunnel is quite simple and a competent DIYer should be able to complete the work easily, assuming safe access has first been gained.

Roof windows are more difficult to install, especially if the roof has deep rolling profiled tiles such as these.

If you’re a competent DIYer but aren’t comfortable working on a roof, you could instruct a roofing company to fit the tunnel or window and then finish off the internal work yourself to save money.

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