We swapped our kitchen fluorescent tubes with a 2'x4' led panel and are super happy with it. To answer your question though I would find out how much light you had before and then adjust up or down depending on how happy you were with the previous setup.

This topic is more complicated than you think, but this should help:

Short form: it's possible (but difficult) to have a workspace that's too bright. Many designers/builders are stingy with fixtures, and we don't realize how dim a room is until it's properly lit.

For a 100 sq ft kitchen, 10K lumens may be a touch high but it's not exceptionally bright.

About 100 lumens per square foot (10k lux/M^2) is what I think of as "drugstore bright" - it's good enough for workbenches etc. It's equivalent to a shady spot on a bright sunny day. (50-100 lm/ft is a good go to for a well lit area)

Remember to get as high as CRI as you can; it makes a difference!

Here's a guide that's focused on workshops, start at

"How much light do I need?"

https://www.woodcraft.com/blog_entries/workshop-lighting-1

Edit: this is a few years old, but addresses kitchens specifically.

https://www.proremodeler.com/sites/proremodeler/files/Kitchen%20Lighting%20Done%20Right_PR0216.pdf

What's your goal, more light/lumens or less power consumption? Or both?

I replaced our 4 tube fixture after trying to use led tubes to replace the florescent tubes, but the thing was so old that the ballast immediately buzzed very loudly. So I replaced the whole fixture with a similarly sized led panel from Lowes. End result was more light and less power consumption. And the new panel makes no noise whatsoever. It also looks better as the old unit had a fake woodgrain frame, plus it's plastic lens was yellowing unevenly.

I just went through this and couldn’t be happier with the results.

First, it helps a lot if you have a light meter. I didn’t, but I downloaded an app that works well enough with my phone camera and the required diffuser (a piece of printer paper as instructed by the app)

Second, look up recommended lux for a kitchen. Lots of sites like https://www.archtoolbox.com/recommended-lighting-levels/

You can figure how many linens you need for your space based on distance from lights to surfaces, lighted sq ft, etc. I had to have a friend do this-I couldn’t grasp the formulas which are also out there in abundance

I ended up with 12 recessed LED lights on a dimmer that put out around 840 Lm each, for a 200-ish sq ft kitchen, which gives me 500+ lux on all surfaces, if that serves as any kind of reference at all

LED panels are wonderful.

You can swap the driver in your 4 lamp fixture with a 2 Lamp direct drive driver or a TLed driver, and then run 2 of the correct corresponding lamps and have planty of light. In my experience the color temp is going to affect you way more than the lumen or foot candle. Recently did a lab spaces like this and reduced the lighting from 30 to 25 foot candles and the techs were like this is way to bright. In truth they lost light, but went from an old failing green led to a fresh 4100. For your home I wouldn't go above 3500. Pm me if you need specific products.

LED is the way to go these days. They use less electricity and give off less UV radiation etc.

Fluorescents dim over time,

they were likely closer to 10-15 foot candles when you replaced the bulbs.

Sorta these were first gen LEDs that had dimmed over time. We take readings before and after instillation. But old LEDs start to discolor like florescents. The green tint was real.

The goal is get rid of old generic(and cracked and yellowing) fixture for something nicer since we are remodeling the kitchen, and to switch to LEDs for power consumption. I'd say the amount of light before was fine, I don't need more and don't think I want much less.

I'd be perfectly happy with the standard LED box replacements, but it's my mother's kitchen and my sister isn't going to settle for a new plain box light.

When I saw the old bulbs are 2600 lumens each, I started to worry about the kitchen being dim.

I believe it.

( I've been out of the loop a while, is anyone making a decent LED bulb or strip light that's at 4K Kelvin? )

Philips does an okay job, but we have been using a lot of Keystone LEDs lately and I have been really happy with their performance.

What’s a good CRI level for home use? The top google searches are all from light manufacturers so of course they recommend insanely high CRIs.

80 is a bare minimum.

90 is great. (replace all your CRI 80 bulbs with these)

More than 90 is better still.

--

Kind of like your mattress affects how you sleep, the lights you use affect how you see the world around you. They're invisible in that way, and the extra $5-10 is less than pennies a day over the lifespan of the bulb.

Good lighting will show you what's there.

Bad lighting will make what's around you look dingy, dim, and terrible.

Cool, thanks for the info!

Thanks! I just looked at my past orders and all my bulbs are 80. I can’t wait until they burn out in 15-20 years so I can get 90!

It’s all personal preference. We prefer our main kitchen light source to be very bright and our accents to be warm. Then you just turn on accordingly. A dimmer may also be the solution if you only have the one light source

Edit typo

Wow, with that kind of lead time you should seriously go for the 95+ CRI bulbs!

I put strip LED lights under all the wall cabinets, so they put more light directly down on to the work surfaces. I wired them all together in a junction box, connected a rocker switch under the cabinet, and ran a cable up to the top and along to the double receptacle for the microwave.

Then I did the same with upward-facing LED strip lights along the top of the wall cabinets..... and connected them to the same double rocker switch under the cabinets.

Whole set-up uses standard electrical connectors, boxes and switches, but is still a "plug in" set-up, consistent with the strip lights design as plug in fittings.

If you get an LED panel the rated lumens are what actually come out of the fixture into the room. Since fluorescent bulbs can be placed in any fixture they’re rated on what comes out of the tube, not the fixture itself. Depending on what fixture you have the effective output could theoretically be anywhere from 0-100%. At my company we tend to use 50% of the total rated output of fluorescent tube fixtures as a basis for LED panel selection. This is because fluorescent tubes are omnidirectional, so you tend to lose a lot of light going sideways/upward into the fixture itself. In this case it would be 2600x4/2=5200 lumen LED panel. Now from there we do one test fixture and use meters to do an actual comparison, but it’s a good starting point if you wanna keep things easy. LED panels also tend to have a much wider projection, so it’ll seem like the entire room gets lit evenly vs the spotlighting effects you have from recessed fixtures.

Thank you, I suspected the full 10,400 was unlikely because of the shape of the fluorescent tube, but wasn't sure what kind of estimate to use. 10,000 lumens of LED light would be insane in a kitchen.

We put a cabinet over the sink where there was none before, so the recessed bulb in that space was replaced with an under cabinet strip light. There is an extra outlet up there and an extra outlet where the microwave will go above the stove, so I can add more later.

Yeah, it’s part of what helps the “efficiency” of LED lights. I’m using quotes because the portion of the energy savings that comes from what I was talking about in my last message isn’t actually in the LED tech itself, but in the fact that it’s directional. Even LED tubes only have light shooting in one direction (at least all the ones we use) so it’s very important to orient them in the right direction or you won’t be getting the light where you want it (i.e. in the recessed ceiling fixtures the light could just end up going straight up into the ceiling instead of down in the room).