A sliding patio door costs roughly 20–30% more than a similar-sized French door, but the trade-off is space-saving performance.
Choosing between sliding and French patio doors often comes down to how you use the space inside and outside your home. The typical cost for a standard 1.8m x 2.1m uPVC sliding patio door (supply and installation) is £1,800–£2,500 in 2026, versus £1,400–£1,900 for a French door of the same size (Checkatrade, 2026). Sliding doors save floor space because they do not swing inward or outward, making them the better choice for tight patios or balconies. French doors offer a wider opening (up to 90% of the frame width) but require a clear swing arc, which can block furniture or reduce usable room area.
Aluminium frames cost 40–60% more than uPVC but last twice as long and need less maintenance.
A 1.8m x 2.1m aluminium sliding patio door costs £3,000–£4,500 installed in 2026, compared to £1,800–£2,500 for uPVC (Checkatrade, 2026). Aluminium frames have a typical lifespan of 35–45 years; uPVC lasts 15–25 years before brittle cracking or colour fade (Glass & Glazing Federation, 2026). Aluminium requires only occasional cleaning; uPVC can need repainting or replacement of seals after 10–15 years. For homes where you plan to stay long term, the higher upfront cost of aluminium often pays back over the extra 20 years of service.
The U-value you need depends on the door type 1.4 W/m²K for a new patio door is the legal minimum in 2026.
Building Regulations Part L (2026 edition) require new patio doors to achieve a whole-door U-value of no more than 1.4 W/m²K (GOV.UK Approved Document L, 2026). Triple-glazed units can lower the U-value to 0.8–1.0 W/m²K, but increase cost by 15–25% and add weight that may require stronger frames. A poor U-value above 1.4 will fail Building Control inspection and reduce the home’s EPC rating, which can affect your ability to sell or rent the property.
Quick numbers
| Door type | Typical installed cost (1.8m x 2.1m) | U-value range (W/m²K) | Lifespan (years) | Opening width (%) | Space required for door swing | Security rating (PAS 24:2022) |
|---|---|---|---|---|---|---|
| Sliding uPVC | £1,800–£2,500 | 1.2–1.4 | 15–25 | 50% | None | Yes |
| Sliding aluminium | £3,000–£4,500 | 1.0–1.4 | 35–45 | 50% | None | Yes |
| French uPVC | £1,400–£1,900 | 1.2–1.4 | 15–25 | 90% | Inward or outward swing | Yes |
| French aluminium | £2,500–£4,000 | 1.0–1.4 | 35–45 | 90% | Inward or outward swing | Yes |
| Bi-fold uPVC | £3,000–£4,500 | 1.2–1.4 | 20–30 | 90% | None (folds to side) | Yes |
| Bi-fold aluminium | £4,500–£7,000 | 1.0–1.4 | 30–40 | 90% | None (folds to side) | Yes |
Sources: Checkatrade 2026 price guide, GOV.UK Approved Document L, PAS 24:2022 standard.
The best patio door option for most UK homes is a uPVC sliding door with a U-value of 1.2–1.4 W/m²K and PAS 24 security.
This combination balances cost (£1,800–£2,500), thermal performance, and security without requiring structural reinforcement. uPVC sliding doors avoid the swing-space problem of French doors and the higher cost of aluminium. For homes with direct sun exposure or south-facing patios, a low-E coating (argon-filled) can improve U-value to 1.1 W/m²K at minimal extra cost (Energy Saving Trust, 2026). This option suits most standard 1.8m x 2.1m openings without needing planning permission or specialist installation.
You must verify your installer holds MCS certification if you plan to claim the Great British Insulation Scheme or a local authority grant.
The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. For non-energy-scheme work, FENSA or CERTASS certification is sufficient to comply with Building Regulations for replacement doors. Always check the installer’s registration on the MCS website (MCS Certified, 2026) or FENSA register before signing a contract. Without the correct certification, you risk invalidating your warranty and failing Building Control inspection. how to check installer certification for doors
Bi-fold doors cost 50–80% more than sliding doors but offer the widest opening, ideal for garden-facing rooms.
A 2.4m x 2.1m bi-fold door (uPVC) costs £3,000–£4,500 installed; aluminium bi-folds run £4,500–£7,000 (Checkatrade, 2026). Bi-folds open to 90% of the frame width, compared to 50% for a sliding door, creating a near-open wall. The trade-off: bi-folds have more moving parts (hinges, tracks, folding mechanisms), leading to higher maintenance costs and a shorter lifespan (20–30 years for uPVC, 30–40 for aluminium). If you entertain frequently and have a wide garden-facing room, the extra opening width may justify the higher cost. For standard patio access, a sliding door remains the more cost-effective choice. bi-fold door maintenance guide
