The eight things that change what a door costs

The three that decide whether it is a good door

Core construction comes first. A 70mm solid core is a different product to a thin skin over foam, in weight, in insulation and in how it takes an attack.

Frame replacement is second. A new slab in an old frame keeps the original keeps and hinge fixings, so nothing about the security specification is certified on your house. Third is the cylinder, because cylinder snapping is the most common forced entry method on modern doors and a TS007 3 star unit is the specific defence against it.

• Core: solid 70mm against a skinned foam panel
• Frame: replaced as a tested doorset or left in place
• Cylinder: TS007 3 star anti snap, or a basic euro cylinder

The five that decide what it costs to build and fit

Glass type and area, since laminated costs more than toughened and a decorative panel is a made item. Size and configuration, because side panels and top lights enlarge the frame. Colour, especially dual colour. Threshold detail, particularly where level access is wanted. And access on the day.

None of these five make a door more secure, which is why they are the right place to economise if the budget is tight and the wrong place to spend if the first three have been cut.

How to use this on a quote

Ask for the core thickness in millimetres, confirmation that the frame is being replaced, and the cylinder standard in writing. Three short questions, and any installer who cannot answer them plainly has told you something useful.

Then compare the remaining differences knowing they are choices about appearance and convenience rather than about how the door performs.