An annexe is a separate dwelling that is attached or located adjacent to a larger property. It can be a self-contained unit or a converted space within the main house that is used for additional living space. Annexe properties can be popular among homeowners who need additional space for family members or for those who are looking for a rental property to generate extra income. In this article, we will explore the pros and cons of annexes, their costs and energy performance ratings.


Extra living space: Annexe properties can provide extra living space for families, which is particularly useful if you have elderly parents or adult children living with you.
Rental income: If you have an annexe on your property, you can rent it out to generate extra income. This can be particularly useful if you live in a desirable location or near a university.
Added privacy: If you have guests staying in the annexe, it can give them added privacy and independence from the main house.


Planning permission: Depending on the size and intended use of the annexe, you may need planning permission from your local authority.
Cost: Building an annexe can be costly, particularly if it requires significant modifications to the existing property.
Maintenance: As with any property, annexes require regular maintenance to ensure they remain in good condition.

The cost of building an annexe can vary significantly depending on the size, type, and location of the property. A basic self-contained unit can cost as little as £20,000, while larger, more luxurious annexes can cost upwards of £100,000. Other costs to consider include planning permission fees, building regulations, and ongoing maintenance and upkeep costs.

Energy Performance Ratings:
The energy performance of an annexe will depend on its size, age, and construction. Most annexes are newly built or recently converted, and will therefore have a good energy performance rating. However, it is important to ensure that the annexe is properly insulated and has efficient heating and hot water systems to minimise energy usage and costs.

In conclusion, annexes can be a great addition to a property, providing extra space and rental income opportunities. However, they can be expensive to build and require regular maintenance. It is important to consider the pros and cons, as well as the costs and energy performance ratings before deciding whether an annexe is right for your property.