Window energy ratings and your EPC in Malta

Most homeowners meet the Energy Performance Certificate at the worst possible moment: a week before the konvenju, when the notary asks for it. It is worth understanding earlier than that, because the rules that govern it also govern what happens when you take the apertures out of a house.

When an EPC is required

The Energy Performance of Buildings Regulations, S.L. 623.01 — Legal Notice 47 of 2018, since amended by LN 134/2020, 409/2021, 231/2022, 305/2023 and most recently LN 153 of 2026 — transpose Directive 2010/31/EU into Maltese law. They require an EPC when a building is constructed, sold or rented. It must be shown to the prospective buyer or tenant and handed over before the promise of sale or the rent agreement, not at the final deed. Adverts must display the rating. For dwellings, this has been compulsory on sale or rent since 2 January 2009.

A certificate lasts ten years unless the building undergoes a major renovation. It is produced by an assessor who must be independent and registered with the Building and Construction Authority, and it comes with a recommendation report of cost-effective improvement measures.

Two details matter to buyers. First, if the seller or landlord does not provide an EPC, the buyer or tenant may commission one and deduct the cost. Second, Grade 1 and Grade 2 scheduled buildings are exempt — which, in Valletta, the Three Cities, Mdina and the Gozitan village cores, covers a lot of houses.

Shell-form property sits awkwardly here. A shell is a building, and the regulations attach to construction, sale and rent rather than to finishing, so an EPC is part of the transaction paperwork; what the rating of an unglazed, unfinished shell means in practice is not something our sources address.

The 5% and 25% triggers

This is where apertures stop being a private matter between you and your contractor.

Regulation 8 of S.L. 623.01 requires a perit's or engineer's compliance certificate where glazed elements amounting to more than 5% of the building envelope are replaced. The equivalent threshold for opaque elements is 10%. Five per cent of the envelope is not a large job. A terraced house having its front and back apertures done can pass it.

Separately, the regulations define a major renovation as including the renovation of 25% or more of the windows, roofs or external walls. Where that applies, the owner must give the BCA a perit's or engineer's compliance certificate within one month of completing the works and before the building is used. A major renovation also ends the ten-year validity of any existing EPC.

None of this is a planning matter. Under the Development Notification Order, S.L. 552.08, Schedule I, Class 1(ii), replacing apertures is permitted development unless it materially alters the character of the building — and in scheduled buildings or those of conservation value, restorable original timber apertures must be retained and restored rather than swapped. Planning permission and building-performance compliance are two separate questions, and clearing one does not clear the other. In an apartment block, the condominium deed is a third.

The number we could not confirm

S.L. 623.01 requires buildings to comply with Technical Document F (2023), published by the BCA in three parts: Part 1 Dwellings, Part 2 Non-Dwellings, Part 3 Technical Building Systems. The regulations state that requirements are reviewed at least every five years.

We could not read Part 1. Both bca.gov.mt and epc.gov.mt returned a Cloudflare challenge, and we did not get past it. So the current maximum window U-value, and whether there is now a g-value limit, are unconfirmed here.

What is sourced is the 2015 edition, as reported in the Ecofys study for Glass for Europe:

Two qualifications from the same source. Each new envelope element had to meet the maximum U-value even for a single window — but the window U-value rule applied only where windows and glazed doors make up at least 20% of the exposed wall. For major renovations, the overall energy demand per m² was capped at the highest dwelling-typology limit.

Treat 4.0 W/m²K as history, not as the law today. If you need the live figure, download TGD F 2023 Part 1 yourself through a browser.

The grant threshold is stricter, and it is a different thing

The REWS RIDG 2023 retrofitting scheme pays 50% of eligible cost including VAT, capped at €1,000 for double glazing, and has been extended to 31 December 2026 by GN 2031/2025. It is first come, first served. Part A must be submitted before you purchase. The product and the retailer must be REWS-registered, the finished unit must reach 3.7 W/m²K or better, the property must be your own primary residence (owner, or lessee of more than five years), the work must be fitted within six months, and a five-year warranty applies. The 3.7 figure is backed by a manufacturer's conductivity certificate plus the installer certifying the gap. For roof insulation the scheme asks for U no greater than 0.4 for the whole roof, certified by an architect.

That threshold is a condition of being paid, not a building regulation. Whether funds remain in the scheme is something we have not verified — ask REWS. Budget 2027, due 26 October 2026, may change the picture. The Birżebbuġa 2024 scheme, BCA Irrinova Darek 2026 and PA Irrestawra Darek 2026 are closed.

Why U-value is the wrong thing to obsess over here

A 2016 M.Sc. dissertation at the University of Malta (Etienne Magri) modelled glazing systems in the central Mediterranean climate and reached an uncomfortable conclusion: g-value — solar gain — was left out again in the 2016 revision of Technical Document F, and in Malta, beyond a point, lower U-values stop helping and can raise cooling loads. On that analysis g-value is the most important glazing parameter here, not U-value.

The orientation findings were specific. Solar-control double glazing performed best facing south. Spectrally selective low-e performed best east, west and north. Plain uncoated double glazing — the local norm — was the least effective of those tested. The dissertation argues that double-glazing incentives may be counterproductive without g-value criteria.

We are not going to turn that into a promise about your bills, and nothing in our sources quantifies a saving or a payback for a Maltese house. But it does mean that a south-facing Gozitan façade and a north-facing Sliema flat are not the same problem, and a specification that only quotes U-value is answering half the question.

What is coming

The recast EPBD, Directive 2024/1275, had a transposition deadline of 29 May 2026 and brings a common EPC template and common class criteria, renovation passports, and targets to cut residential primary energy use 16% by 2030 and 20–22% by 2035. Malta's S.L. 623.01 was last amended by LN 153 of 2026. Expect the EPC you are handed in a few years to look different from the one issued today.

Where this lands on a real job

Prices published in Malta give you orientation, not a quote: ready-made standard PVC windows run €169–319 supply only and PVC doors €509–579 supply only; aluminium is guided at €200–450/m² non-thermal and €350–700/m² thermal break; a two-panel sliding door €700–2,000; a fly screen €40–120; stripping, repairing and repainting timber persjani €150–400 a pair. There is no published fitted PVC price, no published double-glazed unit price and no published price for new persjani — those are quoted after the measure-up.

We survey and measure every job ourselves. Delivery is either by us as contractor, using CheckYourTraders-verified installers, or by a vetted partner who contracts with you directly. Either way, the compliance certificate under regulation 8 is a perit's document, and if your job crosses the 5% glazing threshold you need that perit engaged before the old apertures come out — not after. In Gozo, add the ferry to every delivery when you plan the sequence.