Can a non-student dependant affect my health insurance price? 

Yes. A non-student dependant can affect your health insurance price. 

If you have a child aged 18 to 31 who is not a full-time student, they may be covered as a non-student dependant on your policy, which may result in a higher premium. Non-student dependants can include those who are adopted, foster and stepchildren. 

Health insurers are allowed to set their own definition of a non-student dependants, and may cap the age limit below 31 years of age. They may also require non-student dependants to be living at home, so check your insurer’s rules for non-student dependants.