We already have one woodburning stove which we love but we also spend time in another room that has a nice stone fireplace and a standard 16″ open fire. but since getting the first stove I hate the way an open fire is so uncontrollable.
So I was thinking about putting an inset stove in – but do they give off more heat than an open fire?…I would have thought so but wanted to check!

yes absolutely loads more, think of it ike a wood burnere enclosed in a box with vents at the top and bottom for the air to circulate out – not as good at heating the room [just as good at heating water if a boiler is fitted] as a wood burner but way better than an open fire.

You will notice the difference.
You could probably achieve as much putting a huge metal plate /chimney in /on your open frire though to radiate out heat]
It is far more controlable as well than an open fire

Would doend on cost and use tbh – there are deals on ebay as I did consider it for the same reasons as you but knocked the fireplace out in the end.