I can’t directly answer your question as I have to admit I don’t have the slightest clue how it works with downlighters. What I would say though is ask your electrician. I left it up to mine to work it out, he asked me various questions and it worked out fine. Electricians should have the knowledge for this so involve them.

Is there any windows in this kitchen area?

I really don't like downlights at all, hate the runway look too. I'd only have them if absolutely needed eg if there are no windows in your kitchen area. And they'd need to be dimmable too.

I don't like strip lights above/below units either.

In our kitchen 6m x 5m we have 2 pendants above island and 2 wall lights. We have bifold doors and 2 veulx which bring in loads of light.

Thanks @Ellie, unfortunately no windows as the living area is in the extension and the front is a typical terraced London house...so need good artificial illumination!

Think about how much this is costing and then consider investing a small chunk in some advice from a lighting consultant. You have a space that will receive very little natural light, which in itself will have an impact on how colours will look. I am really sensitive to lighting and hated the LED's in my kitchen. I was convinced they looked greenish even though they were the correct colour temperature. CRI is something that isn't mentioned much but you really need high CRI (colour rendering index) lights to get the balance right. We changed our standard cheapish LEDs over to anti glare CRI downlight and the whole atmosphere in the kitchen changed, the effect is more like the old halogen dichroic lights. I would seriously consider getting some advice from a lighting consultant to make sure it is done properly, electricians tend to put things in a grid.

I would recommend that you work with a lighting designer.

Personally I hate grids of downlights - it looks like the runway at an airport! Also it's not great because you get a dark ceiling and the best kind of lighting is more indirect with planes lit rather than direct pools of light. Downlights are great for task lighting but terrible for general lighting.

Less bad in a kitchen where a lot of worktop tasks take place though. But you can get a much more moody and atmospheric look that will feel much more enjoyable with other forms of lighting.

A decent electrician will be able to advise from experience. But with lighting the intensity is also affected by distance so if you have very high ceilings you will have less light, twice the distance is a quarter of the light. Your electrician can also zone the lighting so not all the downlights operate from one switch.

The quantity of downlights depend on the lumen output of a fitting, height of the room, reflectance of the walls, maintenance factor and the achieved lux levels in a space. 20 downlights are way too much. You need to take the power consumption with 20 downlights into consideration as a health and safety constraint. As per best practice we aim for 200 lux on the floor and 500 lux on working tops. Usually the counter top light levels are achieved by an additional linear lighting mounted below the cupboards. To verify your design I could run the lighting calculations in my lighting software. Probably it would need me about 1h-2h to verify your design given you provide me with your 3D model. If interested, feel free to contact me on www.light-dew.com.
Good luck.

Best wishes
Nitika

Hi Dominic, if you’re feeling like really getting into it you can download Dialux Evo for free - it’s professional lighting simulation software used by lighting designers and it’s free of charge. Takes a bit of effort to learn but you sound like you are interested. It enables you to create a 3D model of a room, install various lights in it and see what the light looks like. You can then experiment with dimming levels. There’s also a function to see the lux levels on various surfaces to meet the recommendations mentioned above. I used my furlough time to learn it and have been enjoying creating the lighting plan for my kitchen renovation. Good luck with whatever you decide.