FENSA, A-rated windows and what Spain uses instead
FENSA certificates and BFRC energy ratings do not exist in Spain. Here, the proof of a good window is its CE marking, its Declaration of Performance and a quote that states the Uw and the g-value.
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Last reviewed: 26 September 2026
FENSA and the BFRC window energy rating are UK schemes, and neither applies in Spain. Here, windows carry CE marking under the European standard UNE-EN 14351-1 and come with a Declaration of Performance. They must also meet the Spanish building code, the CTE. Ask for the Uw and the g-value in writing, not a letter rating.
UK terms and their Spanish equivalents
| In the UK | In Spain | What to ask for |
|---|---|---|
| FENSA certificate | No equivalent scheme. Windows must carry CE marking and meet the CTE building code. | The Declaration of Performance (Declaración de Prestaciones) of the window. |
| Window energy rating (A++ to E) | Not used. The performance values are declared one by one. | Uw, air permeability class, water tightness class and wind resistance class. |
| U-value | Uw (whole window), Uf (frame) and Ug (glass). | The Uw of the whole window, not the Uf of the frame alone. |
| Solar gain (g-value) | Factor solar (g), from the glass data sheet. | A low g-value on south- and west-facing openings. |
| Air leakage (L-value) | Air permeability class under UNE-EN 12207. | The class, written on the quote. Class 4 is the highest. |
| Building Regulations, Part L | CTE, Documento Básico HE (energy saving). | Confirmation that the new openings meet DB-HE. |
What FENSA and the BFRC rating are
FENSA is a Competent Person Scheme for window and door installers in England and Wales. Its certificate shows that replacement windows meet Building Regulations and were registered with the council.
The BFRC rating grades a window from A++ to E. It is an energy balance: solar gain counts as a benefit, while heat loss and air leakage count against the window.
Both schemes belong to the UK system. They are not part of Spanish rules, and a fitter in Spain does not issue them.
What a window sold in Spain must have
A window sold in Spain must carry CE marking under the harmonised European standard for windows and external doors, UNE-EN 14351-1. The manufacturer must also issue a Declaration of Performance.
The Declaration of Performance lists the tested values of that window. Typical ones are the U-value, air permeability, water tightness and resistance to wind load.
These rules come from the EU Construction Products Regulation, Regulation (EU) No 305/2011. The EU is replacing it in stages with Regulation (EU) 2024/3110.
Under article 94 of the new Regulation, the rules of 305/2011 on the Declaration of Performance and CE marking remain until 8 January 2040.
What the Spanish building code asks of windows
The Spanish building code is the Código Técnico de la Edificación (CTE). Its energy section is the Documento Básico HE. It sets limits by climate zone.
The low-lying coast of Alicante province is climate zone B4. The letter measures how hard the winter is and the number how hard the summer is. B4 means a mild winter and a demanding summer.
In winter zone B, the U-value of an opening must not exceed 2.3 W/m²K. This covers the frame, the glass and, where there is one, the shutter box.
In a renovation, that limit applies to the elements you replace. A modern uPVC window with low-E double glazing is well inside it.
Air permeability of new openings in zones A to C must not exceed 27 m³/h·m² at 100 Pa. That is class 2 under UNE-EN 12207. A good window reaches class 4.
For new buildings and large renovations, DB-HE also limits the sun that enters through the windows in July. Spain's own code treats summer sun as a problem to control.
What is inside a uPVC window
The whole process in a minute and a half. You see how the profile is made, where the steel goes, how the corners are welded and how the glass goes in. This is what you cannot see once the window is on your wall.
Why an A rating can mislead on the Costa Blanca
The BFRC rating rewards solar gain, because in a heating climate free heat from the sun saves energy. On the Costa Blanca the same sun heats your living room in July.
The AEMET weather station in Alicante records about 2,850 hours of sunshine a year (1981–2010 normals). Winters are mild, and frost on the coast is rare.
So a window with a high g-value can score well on the UK scale and still make a west-facing room too hot. Here, the g-value on south and west openings matters more than an extra tenth of U-value.
Read more in our guide to glass for the Spanish sun.
What to ask for in writing
- The profile manufacturer and system name, and the Declaration of Performance.
- The Uw of the whole window, and confirmation that it is not the Uf of the frame alone.
- The glass make-up, its Ug and its g-value.
- The air permeability class (UNE-EN 12207), water tightness class (UNE-EN 12208) and wind resistance class (UNE-EN 12210).
- How the joint between frame and wall is sealed.
- The guarantees: profile, glass, hardware and installation, one by one.
In short
Tu Ventana Costa Blanca, the Benidorm office of Tu Ventana Madrid, makes and fits Kömmerling uPVC windows for English-speaking homeowners on the Costa Blanca. Instead of FENSA or a BFRC rating, each written quote states the profile system, the glass make-up, the Uw and the g-value. The Kömmerling profile carries a manufacturer guarantee of 10 years.
See our uPVC windows and the Kömmerling systems we fit.
Sources
- FENSA: about FENSA (England and Wales)
- BFRC: energy performance and ratings
- Regulation (EU) No 305/2011, Construction Products Regulation (EUR-Lex)
- Regulation (EU) 2024/3110, new Construction Products Regulation, article 94 (EUR-Lex)
- CTE, Documento Básico HE: energy saving, tables 3.1.1.a, 3.1.2 and 3.1.3.a, and Annex B climate zones (codigotecnico.org)
- AEMET: standard climate values, Alicante/Alacant station, 1981–2010
Get a quote you can check line by line
We measure on site and send a written quote with the profile, glass, Uw and g-value. Ask for a free quote.
Eduardo answers in English on WhatsApp, 9:00–20:00 Spain time (8:00–19:00 UK time).
Questions about FENSA and energy ratings in Spain
Last reviewed: 26 September 2026
Do I need a FENSA certificate for new windows in Spain?
No. FENSA covers England and Wales only. In Spain, windows must carry CE marking under UNE-EN 14351-1, come with a Declaration of Performance and meet the CTE building code.
Is there an A-rated window label in Spain?
The BFRC scale is not used in Spain. Compare windows by their declared values instead: Uw, g-value, air permeability, water tightness and wind resistance.
Is an A-rated window the right choice for the Costa Blanca?
Not always. The UK rating counts solar gain as a benefit. On this coast, summer sun is the main problem, so a low g-value on south and west openings matters more.
What U-value do Spanish rules require for windows here?
On the low-lying Alicante coast (climate zone B4), the CTE limit for an opening is 2.3 W/m²K, including the shutter box. Modern uPVC windows with low-E double glazing are well inside it.
What is a Declaration of Performance?
It is the document in which the manufacturer declares the tested values of a construction product, such as a window. EU law requires it for CE-marked products.
What is the difference between Uw, Uf and Ug?
Ug is the glass alone, Uf the frame alone and Uw the whole window. Ask for the Uw: the frame value alone always looks better. Our glossary explains more terms.