New kettle with a whistle for gas hob, is it worth using?

Hi.  I have a gas hob and also bought myself a hob kettle.  We used this for a time but didn’t see much of a reduction on our monthly bills so I also bought myself a large insulated thermos flask.  Now we boil a filled  electric kettle then fill the flask, using the water from the flask for drinks/cooking during the day.  Two filled kettles does tea for most of the day.

More of a concern is the amount of electricity used by our electric oven.  Having a small kitchen I don’t have much room for an Air Fryer but wondered if anyone uses one instead of an oven and if so, are you seeing much of a saving on monthly bills?

We purchased an air fryer a few months ago and now only very rarely use the oven. 
From what we’ve monitored, the air fryer uses around 1/3 of the energy of the oven - bear in mind that will depend on your oven and which air fryer you get but look at the kw power on each to check

Yes we have used a air fryer for years on our second one .

we like the glass ones which you can cook at 2 levels and also expands upwards as then you have a larger cooking area .Compared to the air fryer my daughter has with two drawer section . Lots of yummy food can be made 

Also a slow cooker is used occasionally which also contributes to lowering energy levels.

So main oven only used very occasionally .

We cook for 4 and eat for 2 freezing portions for the future .

Gas hob kettle definitely cheaper than electric, we only use our hob kettle.  Shame about using gas, but it is cheaper.