You will reduce the amount of energy you use by a significant amount. This will reduce your carbon emissions and save you money.
Do an EIA (Environmental Impact Assessment)
Hot air rises so most heat loss is through the roof - ensure that it is properly insulated.
Insert triple (or double at least) glazed windows.
Insulate your floors - ideally install underfloor heating as this is the most effective
Insulate your cavity walls - if they are solid, book shelves help!
Use thick curtains.
Insulate your tanks and pipes
Draught-proof your home by sealing any cracks, holes, gaps or chimneys with door brushes, beading, and rubber seals.
Keep your indoor and outdoor doors closed to conserve heat.
Make use of government grants for insulating your home:
https://www.gov.uk/guidance/apply-for-the-green-homes-grant-scheme
In order to keep warming below 1.5C we need to halve emissions by
2030. Share this action and help play a part in reversing climate change.