Composite vs uPVC Door | What a Locksmith Would Choose

You're standing in a showroom in Bolton or clicking through a double-glazing website at midnight, and everyone wants to sell you a door. The composite salesperson says uPVC is old-fashioned. The uPVC rep says composite is overpriced. Neither of them is lying, exactly. But neither is telling you the whole truth either.

Here's what I'd actually put on my own house. And more importantly, why.

The slab is not the security

I'll say this plainly because the showrooms won't: the door panel itself is rarely where a burglar gets in. Kick-ins on a decent modern door are uncommon. What fails is almost always the cylinder or the multipoint gearbox. A weak euro cylinder can be snapped in seconds with a pair of pliers and a screwdriver. A worn-out gearbox fails to hook the door properly, and a shoulder barge does the rest.

So before you spend £1,500 more on a composite door versus a uPVC door, ask yourself what cylinder and what gearbox either door is fitted with. If the answer is a standard Yale or ERA cylinder and a budget mechanism, you're paying for aesthetics, not security.

That said, composite and uPVC aren't identical. Let me give you the honest differences.

What composite actually gives you

A composite door has a solid timber or foam core, usually around 44mm to 48mm thick, wrapped in a glass-reinforced plastic (GRP) skin. It doesn't flex or warp the way uPVC does over time. In Horwich, where we get a proper winter and the BL6 postcodes sit at some altitude, thermal movement matters. A warped uPVC door is a nightmare: the multipoint locks won't engage cleanly, the gearbox strains on every turn of the key, and eventually something gives.

Composite holds its shape better. That's a real, practical benefit. It also looks closer to a timber door, which counts for something on the older semis around Wallsuches and the Victorian terraces near the town centre.

But you're paying for that. Installed, a decent composite door runs from around £1,400 to £2,200. A mid-range uPVC door with the same ironmongery spec comes in at £700 to £1,200.

What uPVC actually gives you

Plenty. Modern uPVC doors are reinforced with steel, they take the same high-security cylinders and multipoint gearboxes as composite, and they're easier and cheaper to repair when something goes wrong. On the new-builds around Lostock and Middlebrook, you'll find uPVC doors that are perfectly secure because someone's fitted them with a decent cylinder.

uPVC also handles the rain better in terms of maintenance. No painting, no swelling. The frame can degrade with UV over many years, but a door bought in the last decade won't give you trouble for a long while.

Where uPVC loses is thermal stability. A hot summer followed by a cold November can cause enough movement that multipoint locks start to feel stiff. On cheaper profiles this is worse. On better profiles (Mila, Maco) it's much less of an issue.

The hardware is where you actually spend wisely

Whichever door you choose, this is where I'd put the money:

The cylinder. Get a TS007 3-star rated anti-snap cylinder. Ultion and Avocet ABS are both excellent. Mul-T-Lock is solid. I've written about this before but it bears repeating: a 3-star cylinder on a uPVC door beats a standard cylinder on a composite door every single time. Cost is £50 to £120 fitted. Not an optional extra.

The gearbox. This is the multipoint locking mechanism inside the door. GU, Fuhr, Lockmaster, Winkhaus and Maco all make reliable gearboxes. If your installer is fitting a budget no-name mechanism to save £30, that's where I'd push back. A good gearbox costs around £80 to £160 fitted and can last 20 years. A bad one will let you down in five.

The letterbox and handle. Both are attack points. A letterbox restrictor costs a few pounds. A solid handle escutcheon with cylinder guard covers the cylinder from direct grab attacks. Small things, genuinely useful.

Cost comparison at a glance

The gap between a well-specified uPVC door and a mid-range composite is roughly £500 to £700 fitted. That's real money.

So which would I fit on my own house?

Honestly? Composite, but not for the reason the showroom gives you.

I'd choose it because a composite door stays true in its frame year-round, which means the multipoint locks engage properly every time, which means less wear on the gearbox and less chance of a fault developing quietly over winter. On a detached or semi in Brownlow Fold or up towards Blackrod, that's worth the premium over fifteen years of ownership.

But, and this matters: I'd insist on a TS007 3-star cylinder from day one, even if the installer tries to quote me a standard one. And I'd check the gearbox brand before signing anything.

If budget is tight? A mid-range uPVC door from a reputable profile manufacturer, fitted with an Ultion or Avocet ABS cylinder and a GU or Fuhr gearbox, is a secure front door. Full stop. It's not a compromise that keeps me up at night.

What does keep me up is the composite door on a property in Aspull that a homeowner paid £1,900 for, fitted with a builder-grade cylinder that snaps in eight seconds. The door looked beautiful. The lock was the cheapest part of the job.

Spend the money in the right order

1. Get the cylinder right. Non-negotiable, first thing, cheapest fix relative to impact.
2. Make sure the gearbox is a named brand and the door engages cleanly on all hooks.
3. Then consider whether composite or uPVC suits your budget, your house style, and how long you're staying.
4. If you're renting out a property in Westhoughton or Adlington, uPVC is usually the sensible call: easier to repair, cheaper to replace if it gets damaged.
5. If it's your home for the next decade, composite earns its price in stability and longevity.

The door salesperson wants to sell you the door. I'm trying to tell you that the door is the frame. What goes inside it is what actually matters.

If you want a second opinion on what's already fitted, or you're upgrading an existing door and want the cylinder and gearbox assessed, Locks Local covers Horwich and the BL postcodes and I can usually be with you in under 30 minutes. Pricing is given honestly on the call before any work starts.