Other factors can affect the average cost of a conservatory:
Size of floorplan – this is quite obvious that the bigger the conservatory, the more it will cost. Although, small conservatories are not necessarily much cheaper because you still have all the installation costs and a bigger conservatory might work out cheaper on a cost per square foot comparison.
Style – the most popular style of lean-to, Victorian and Edwardian all differ in price, with lean-to being the cheapest option. The different options available for glazing and styling all will make a difference to your cost.
Flooring – often overlooked, but you do need to consider what style of floor you would like – tiled, wooden, laminate, carpet. Underfloor heating is a popular choice in a conservatory for heating in colder months.
Amount of doors and opening windows – a standard conservatory might have two French doors and 2-4 opening windows. If you want more doors to open into the garden or even a wall of bi-fold doors this can raise the cost considerably.
Ground preparation/complex foundations – any structure is only as strong as the foundations it sits upon to distribute the load. And, all construction work is dependent on your unique ground conditions – the type of soil, over old mining shafts or landfill, trees and the dreaded drains and sewers. Most foundations are straight forward but if you come across a problem the cost does escalate.
Opening up walls from the house – technically a conservatory should be connected to the house by a closing door or window. Many homeowners choose to make an open plan space with their conservatory and that involves removing the adjoining wall. This is another expense that makes a huge difference, depending on if you need to insert beams and lintels to keep the open wall strong.
Brick base or full glazing – traditional conservatories have a fully glazed wall frame to the floor but some styles such as Edwardian have a small brick wall. The option to add brickwork at the base of your wall will make the space warmer and more like a traditional room. Many people do have a hybrid structure that sits between a conservatory, orangery and an extension.
Heating, electrical points, TV point – the small details can add the most costs and are often not considered. If you're using the space as an office or a family room you will need a power point and a TV co-axial point. Technically a conservatory has a heating source separate from the house (for building regulations) so you need to think about how you will heat the space and factor that into the cost.