It’s always a good idea to check out your windows, if you are in an older house, as they could be older style single glazed. And therefore will not be good insulation, they will let in drafts and it will cost you more in fuel bills.
Your windows, have to be double or triple glazed these days to ensure they keep the warmth in and cold out, you will be surprised how good glass windows will save you in the long run.
They also look very stylish or can do, as there are so many designs and so many glaziers to install them for you, also a lot of glazing companies, from local, regional and even national who will give you a good price to change out your old cold windows for some new double glazed ones or even triple glazed ones.
Go do it, we did, we used a great glazier – Hamlets Glass 24/7 and they were fantastic.