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Gerda THERMO PRIME
The 75mm mid-spec residential steel security door in the Gerda range. Whole-door U-value 0.79–0.9 W/m²K (better than premium composite alternatives), RC2 standard under BS EN 1627:2011, up to 12-point multi-point locking with anti-snap cylinder, 200+ RAL colour options including wood-effect transfers. The practical premium choice when you want Gerda quality without paying for ALTUS's extra thermal headroom or THERMO PREMIUM's RC3 upgrade option. Vitrum Solutions installs Gerda THERMO PRIME across Buckinghamshire, Berkshire, Oxfordshire, Surrey and Hampshire.
THERMO PRIME Specifications
Range
Gerda THERMO PRIME — 75mm mid-spec
Door Thickness
75 mm
Thermal
U-value 0.79 – 0.9 W/m²K
Security
BS EN 1627:2011 RC2 standard
Why THERMO PRIME
75 mm — the practical mid-spec
THERMO PRIME is the 75mm mid-spec door in the Gerda residential range. It sits between the 88mm ALTUS (top thermal) and the value tier — same multi-point locking, same anti-snap cylinder, same 200+ RAL colour range as the higher specs, with thermal performance still better than any composite door on the market. The right spec when you want premium Gerda quality without paying for the extra thermal headroom of ALTUS.
U-value 0.79 – 0.9 W/m²K — better than premium composite
Whole-door U-value of 0.79–0.9 W/m²K — better thermal performance than premium composite door alternatives like Palladio (0.85 W/m²K solid / 0.98 W/m²K glazed). Multi-layer insulation core (steel skin + mineral wool + polyurethane foam + second steel skin) plus thermally broken jamb and threshold. Easily exceeds Approved Document L for a residential entrance door.
BS EN 1627:2011 RC2 standard
RC2 certification under BS EN 1627:2011 as standard. Resists casual forced-entry attempts with simple tools (screwdrivers, pliers, wedges) for at least 3 minutes — long enough that opportunistic break-in attempts are abandoned. Recognised by UK home insurance underwriters; satisfies most premium insurance specifications. For RC3 upgrade (sustained heavy-tool attack resistance), the THERMO PREMIUM and OPTIMA ranges are the alternatives.
Up to 12-point multi-point locking
Hardened steel hookbolts at the lock side plus opposing pins along the hinge side. Anti-snap, anti-drill, anti-pick cylinder — TS007 3-star equivalent. Anti-spread plates around the lock and hinge sides resist crowbar and jack attacks. Same locking spec as the higher Gerda tiers.
200+ RAL colours plus wood-effect transfers
Same external finish range as ALTUS and THERMO PREMIUM — any RAL Classic colour with optional structured/matt/satin finish. Wood-effect transfers (oak, walnut, anthracite woodgrain) on request, indistinguishable from premium composite at conversational distance. Glazed sidelights, bullseye lights and panelled designs available.
Get a free quote for Gerda THERMO PRIME Steel Security Door
Free no-obligation written quote. Fast response times. FENSA registered with a 10-year CPA insurance-backed guarantee. Serving Buckinghamshire, Berkshire, Oxfordshire, Surrey, Hampshire, Hertfordshire & West London.
Other Gerda Ranges
THERMO PRIME is the practical mid-spec. The other three Gerda residential ranges trade off thermal vs security vs price differently.
Gerda THERMO PRIME — Frequently Asked Questions
What is Gerda THERMO PRIME?
THERMO PRIME is the 75mm mid-spec residential steel security door in the Gerda range. Whole-door U-value of 0.79–0.9 W/m²K, RC2 standard certification under BS EN 1627:2011, up to 12-point multi-point locking, and 200+ RAL colour options including wood-effect transfers. Sits between the 88mm thermal-priority ALTUS and the value-tier ranges, with the same locking and finish quality as the higher specs.
How does THERMO PRIME compare to ALTUS?
ALTUS is 88mm thick with U-value 0.74-0.81 W/m²K — the absolute thermal top spec in the Gerda range. THERMO PRIME is 75mm thick with U-value 0.79-0.9 W/m²K — slightly thinner and slightly less thermally efficient, but with the same locking, security and finish quality. Choose ALTUS where every fraction of thermal performance matters; choose THERMO PRIME where the extra thermal headroom isn't worth the price difference for the project.
Is THERMO PRIME RC3-eligible?
No — RC3 burglar resistance upgrade is available specifically on the THERMO PREMIUM and OPTIMA ranges, not on THERMO PRIME (or ALTUS). THERMO PRIME is RC2 standard. If RC3 is a requirement (insurance underwriter spec, higher-risk area), the THERMO PREMIUM or OPTIMA ranges are the alternatives.
How does THERMO PRIME compare to a Palladio composite door?
THERMO PRIME's thermal performance (U-value 0.79-0.9 W/m²K) is better than Palladio's (0.85 W/m²K solid / 0.98 W/m²K glazed). Security is meaningfully higher: RC2 BS EN 1627:2011 vs Palladio's PAS 24:2022 baseline. Where Palladio wins is design flexibility (decorative glazed centre panels, full glass-surround configurations, woodgrain texture) at a more accessible price point. Choose THERMO PRIME for steel-grade security + better-than-composite thermal performance; choose Palladio for the heritage/contemporary composite-door aesthetic.
Why choose THERMO PRIME over a budget steel door?
Most budget steel doors in the UK are imported uncertified or PAS 24-only. THERMO PRIME carries RC2 (BS EN 1627:2011) certification, multi-layer thermal insulation (matching premium composite door performance), up to 12-point multi-point locking with anti-snap cylinder, and Gerda's full 200+ RAL colour and wood-effect finish range. The price step versus a budget steel door is meaningful but the security + thermal + finish step is also meaningful — and the door looks like a premium composite door rather than an industrial steel security door.
Will my insurer recognise THERMO PRIME?
Yes — RC2 (BS EN 1627:2011) is the security rating UK insurers look for. THERMO PRIME satisfies most premium home insurance policies' requirements. For the strictest underwriter specs (typically Hiscox/Chubb/AIG Private Client high-net-worth policies), RC3 may be specifically required — in which case THERMO PREMIUM or OPTIMA are the appropriate Gerda choices instead.
Are you a Gerda Approved Installer for THERMO PRIME?
Yes — Vitrum Solutions is one of the few UK installers of Gerda steel security doors. We supply and fit the full Gerda residential range including THERMO PRIME, with FENSA registration and a 10-year CPA insurance-backed guarantee on top of Gerda's manufacturer warranty. Structural opening survey, weather detailing and finish making-good are all carried out by our own team.
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