Does a dimmer switch save energy?

[Pine]

You will have to forgive my lack of technical knowledge.  In my lounge I have a ceiling light with three bright bulbs in it.  Great for reading but unnecessarily bright in the evening when watching TV.   I was thinking of getting a dimmer switch fitted.  If I use the dimmer switch to dim the lights am I also saving energy?

[JimSh]

New ones Yes
Old ones No

https://www.schaferelectric.com/do-light-dimmer-switches-save-energy/

https://www.electricrate.com/data-center/dimmed-lights/

[olduser1]

Your electricity supplier will ensure any savings are swallowed by the increase in daily standing charge

[Westy36]

You're just showing off that you can still afford to put the lights on!! 

[Kremmen]

These days you'll need dimmable LED's and a LED compatible dimmer switch.

I've got my lounge on LED dimmable but it's only a single bulb. Screwfix do a good range of Varilight LED dimmer switches.

[Jocko]

All dimmer switches reduce energy usage. Even old ones. Just that old ones didn't save very much.

[JimSh]

I thought the older dimmer switches with incandescent bulbs converted some of the electricity into heat rather than light.

[Toptek]

I have been on a mission to replace old school filament bulbs to LED, including replacing 12v halogens on individual transformers to mains GU10 dimmable LED in the kitchen dimmed by a Varialight dimmer.
Also, I have a Varialight feeding 3 ceiling pendants. On occasion I have had to reset the dimmer due to it not attaining maximum brightness, not sure what happened.
If you would like to keep things simple, you could fit smart bulbs if they have BC or ES fitting. I have some in standard table lamps, they are controlled by an app to control brightness, default power levels and schedules etc. These are TP link Kasa bulbs.
One word of advice I received from a contractor was to stick to major brands.

[Jocko]

I thought the older dimmer switches with incandescent bulbs converted some of the electricity into heat rather than light.

The light is caused by heat. You reduce the heat and that reduces the light.

[Toptek]

Thinking about it, if the light is switched on and off from two switches, you may need to explore the suitable options for 2 way switching regarding the dimmer re master and slave switching.

[nowster]

I thought the older dimmer switches with incandescent bulbs converted some of the electricity into heat rather than light.

They'd have to be really old ones with rheostats!

Any dimmer switch made in the last forty years for incandescent lights would have used a triac switching circuit.

[JimSh]

My bad.
My simplistic mind just had a vision of a rheostat controlled system for incandescent bulbs.