All homes are unique; they can be different sizes, made from a variety of different materials and have different quality finishes so it's important that the sum insured reflects this. As you know your home and situation better than us, it makes sense for you to determine your sum insured amount.
If you get an online quote for your home or landlord insurance, you'll notice we've included some questions from the Cordell Sum Sure calculator. This is to give you an indication of how much your sum insured could be. However, it's up to you to check this figure, and make sure it's right for you and your circumstances.
You can find more information around your sum insured and how to calculate this here.