Combi boiler - using hot tap to wash hands

[SomeUnspokenThing]

I've Googled but can't the answer, most likely because it's a bit of a garbled question.... I have a combi boiler which heats the water as needed. Force of habit means I tend to use the hot tap to wash my hands even though I'm not washing them for long enough for the water to be heated up - I'm not running the tap till it's hot and then washing, I just wash my hands in the cold water. Is this costing more than simply using the cold water tap? It's doing my head in trying to find an answer! Thank you in advance.

Why is it baffling ?
Some people leave a pool of gravy or ketchup or some other sauce or grease on their plate. Quick rinse at the time and it is gone. But if you leave it sitting there for several hours, it dries and becomes much more difficult to shift.
The weetabix residue in a dish is a bugger for it.

DC are the sensible ones in my family then because they always use the cold tap after using the toilet. I will follow their lead.

Same thoughts here so I am looking into the cost of installing an electric above sink water heater as so many public areas and work.
instant hot water so low water use and only heating the water used.

Remember how cold the water will be in the winter months. Not good for people effected by the cold.
3 kw water heater for 10-20 seconds can’t be as much as running the combo for 30 seconds before it starts to get warm. Money going to heating the pipes only.
Got to be cheaper

I keep a spreadsheet of usage, i used 8 units of gas last month (7 the month before) but everything is electric with the exception of washing hands. we have a dishwasher, elec shower etc. so that 8 units was just hot water and with the exception of an odd bowl of washing up will have been mostly for hand washing (in cold water because the water takes too long to get to the tap) so yes you are paying gas to wash your hands even in cold water. i have considered turning the boiler off but sometimes you do want hot tap water and dont want to switch it on for that one moment

I do a quick rinse in cold water then use a bit of sanitiser left over from covid.

I boil a kettle in my en suite to wash hands and face morning and night. Yes, I know there shouldn't be a plug socket in an en suite, but there is one so there!

Intrigued why you have a kettle in your en-suite but not a hot water tap? (And I love my tea just as much as anyone)

Likewise, as the route from the boiler to the taps here is tortuously long, it takes ages. I now only wash hands in warm water as a treat when I know the hot has been running immediately before for some other reason. If/when we eventually replumb I'll try to shorten the routes if possible.
Pre energy costs shooting up, to save (metered) water I would run the cold water off first into a bowl and dump it into a bucket outside the back door, and use it for watering plants or whatever.

nuttynotty, i do have a hot tap but I'm trying not to use it, to save gas and thereby defeat Putin singlehandedly.

My OH has done this for years and it really winds me up, especially when they say "but I didn't actually use any hot water!"
Water is being heated by the boiler and is running through the pipe to replace the cold water you are drawing off, if you allow the hot water to reach the tap and actually make use of it then not so bad but when you don't even use the hot water that has just been heated then yes, you are spending money unnessarily.