Lighting Levels

There are two elements when considering Lighting levels for your new house.

  • Electrical Power (Watts)
  • Amount of Light (Lumens)


incandescent bulb

In the old days with incandescent bulbs it used to be simple, bulbs came in 40, 60 and 100watts and you were allowed up to 25 watts/square metre of floor space.

Now for your new build, in order to limit energy consumption, you are only allowed:

  • Indoors 5 watts /sqm (5W/sqm)
  • Outside 4 watts/sqm (4W/sqm)
  • Garages 3 watts/sqm

This doesn’t mean you have to have a gloomy house. 

Modern light fittings such as Compact Fluorescent Lamp (CFLs) and Light Emiting Diodes (LED) give much more light than Incandescent Bulbs.

The above power consumption figure are for the initial construction. (After handover you can add additional lights)


Probably the best way to think about lighting is to consider what task you are going to do.

Then look at how you will provide enough light in that area rather than the whole room.

Here are some suggested light levels for various tasks.

Under 10 lumens/sqm – Outside Security.

10-20 lumens/sqm – Conversation, Eating, Watching Television, General Circulation.

20-50 lumens/sqm – Cooking, Casual Reading, Bathrooms.

50- 100 lumens/sqm – Detailed Craft Work, Study.


A typical LED delivers around 80-100 lumens per watt so a single 10w LED will provide a high lighting level for a 10m2 room (1 watt/sqm)

For more posts see Electrical or Light Fittings



  1. Simon

    There is the stupidity of the entire system, after occupancy you can change it all! There are so many wrong things with the building process – don’t know where to start.

    After nearly 2 years we are almost at the end of the process – BAL ratings, soil tests etc

    What amazes me is just how much more an owner builder has to do in comparison to a someone who uses a surveyor – I know that we will have a better built house and less corners cut – but the standard should be the same.

  2. Nont

    Its disappointing how much these regulations don’t take into account peoples disabilities, as well as their age. I’m getting on in my years and find I need significantly more light to see what I am doing than I did in my younger years.

    1. Brian Ashworth (Post author)

      The good news is that if you go for LED bulbs you will actually get more light than the old incandescent bulbs but save money.

      There will be a post on Wednesday 8th of October which will have a bulb comparison.


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