Windows are the weakest point in any home's insulation. According to Spain's Institute for Energy Diversification and Saving (IDAE), a very significant share of a home's energy losses occurs through its windows. In other words, much of what you pay to heat or cool your home escapes through the openings in the facade.
In the climate of Granada and Malaga, where summers exceed 40 degrees and Granada winters drop below zero, efficient windows are not a luxury but a necessity. A home with old aluminium windows without thermal break spends considerably more on climate control than one with modern windows, and also suffers from condensation and draughts.
At Tecnisun C.B., we have been installing high energy efficiency windows throughout Granada and Malaga provinces for over 25 years. As official STRUGAL installers, we work with the most advanced aluminium RPT and PVC series on the market.
The Uw value (thermal transmittance of the complete window) measures how much heat passes through the window. The lower the Uw value, the better the window insulates. It is measured in W/m²K (watts per square metre per degree Kelvin).
This value includes three components: the profile (Uf), the glass (Ug), and the perimeter spacer effect (Ψg). That is why improving only the glass or only the profile is not enough — the whole system must be optimised.
| Uw Value | Window Type | Performance |
|---|---|---|
| Above 3.0 W/m²K | Old aluminium without RPT | Very poor — Frequent condensation |
| 1.8 - 3.0 W/m²K | Basic improved windows | Insufficient for current CTE |
| 1.2 - 1.8 W/m²K | Quality aluminium RPT (STRUGAL S74RP/S88RP) | Good — Meets regulations |
| 0.8 - 1.2 W/m²K | High-end STRUGAL PVC | Excellent — Maximum efficiency |
| Below 0.8 W/m²K | PVC + triple glazing | Premium — Passivhaus standard |
Not all glass is equal. The right glazing choice makes a noticeable difference to the window's energy performance:
| Glass Type | Approximate Ug | Features | Recommended For |
|---|---|---|---|
| Single (4 mm) | 5.7 W/m²K | No air chamber. Obsolete. | Nothing (fails CTE) |
| Double (4/16/4) | 2.7 W/m²K | 16 mm air chamber | Minimum required |
| Double low-e + argon | 1.0-1.1 W/m²K | Metallic coating + argon gas | Recommended standard |
| Double solar control + argon | 1.0-1.1 W/m²K | Reflects solar heat. Solar factor 0.3-0.5 | South and west-facing |
| Triple low-e + argon | 0.5-0.7 W/m²K | Maximum insulation | Cold zones, Passivhaus |
Real savings depend on several factors: the type of window being replaced, home orientation, climate zone, and your consumption habits. That is why we do not give generic figures: two identical flats in the same building can have very different results if one faces south and the other north. What we can tell you is what changes when you move from an old window to an efficient one:
| Aspect | Old windows (Uw ~5.7) | Efficient windows (Uw ~0.9-1.4) |
|---|---|---|
| Temperature next to the window in winter | Cold spots and draughts | Warm interior surface |
| Condensation on glass and frame | Frequent in winter | Practically disappears |
| Summer heat on south and west facades | Very high | Controlled with solar control glass |
| Use of heating and air conditioning | Constant | Lower and steadier |
| Outside noise | High | Much reduced |
Savings depend on the home, its orientation and how you use it. When we prepare your quote, we take into account the windows being replaced, the climate zone and the orientation of each facade to recommend the profile and glass combination that makes most sense for you.
Stable temperature throughout the home, with no cold spots near the windows and no draughts
Noticeably less outside noise, especially with acoustic glass
No droplets on the glass and no mould on frames and nearby walls
A better energy certificate makes the property more attractive to sell or rent
The energy performance certificate is mandatory for selling or renting property in Spain. Windows are one of the factors with the greatest impact on the rating. The exact improvement depends on the whole building (walls, roof, systems), not just the windows, but replacing old aluminium with modern efficient windows is one of the most effective upgrades you can make.
Andalusia has one of the widest thermal ranges in Spain. Granada city belongs to climate zone C3 (cold winters and very hot summers). Malaga, in zone A3, has mild winters but extremely hot summers with high humidity.
This duality makes efficient windows especially worthwhile in our area, as you notice the difference in both heating and air conditioning. With over 2,800 hours of sunshine per year in Malaga, solar control glass is essential on south and west-facing facades.
Priority: winter thermal insulation. PVC with Uw ≤ 1.0. Double low-e glazing with argon. Solar control on south facade.
Priority: summer solar control. Solar control glass mandatory. Solar factor ≤ 0.40 on south/west. Ideal: aluminium RPT + solar control.
Priority: maximum insulation. PVC with triple glazing. Uw ≤ 0.8. Anti-corrosion hardware for altitude.
Heat/cold balance. PVC or aluminium RPT depending on each home's needs. Double low-e + argon minimum. SAXUN screen blinds for exposed facades.
Public administrations periodically open calls to improve home energy efficiency. Requirements and amounts change with each call.
Grants for the energy renovation of homes and buildings, subject to each programme's requirements and deadlines
There are deductions for energy efficiency improvement works; whether they apply depends on your tax situation
Check the calls currently open before deciding; we advise you on your case and provide the technical documentation for the windows we install. Read our subsidies guide for more details.
Efficient windows are the foundation, but to get the most out of them, combine them with solar protection systems:
At Tecnisun C.B. we review your current windows and recommend the most efficient solution for your home. Official STRUGAL installers with over 25 years of experience. Tell us about your project in our quote request form: the online quote is free and with no obligation (the technical home visit has a cost, which we tell you before arranging it). You can also call 627 84 14 04.
See all windows →Is it worth replacing windows in a rental property?
If you are the landlord, yes: efficient windows improve the property's energy certificate and prevent complaints about condensation or noise. If you are a tenant, talk to your landlord about any grants that may be available.
Can I replace just the glass without changing the frame?
Technically yes, but we do not recommend it for aluminium frames without thermal break. The old frame remains a thermal bridge causing condensation. The ideal approach is to replace the complete window.
How long until the investment pays for itself?
It depends on the windows being replaced, the orientation and use of the home, and whether you can benefit from any grant. What is certain is that well-chosen, well-installed windows perform for decades, and the comfort is noticeable from day one.
Is the quote free?
Yes. The online quote is free and with no obligation: you send us approximate measurements and photos and we prepare the proposal. The technical home visit has a cost, which we tell you before arranging it.
A window's rated Uw value is only achieved with correct installation. Poor installation can seriously degrade thermal performance and negate much of the investment. Common errors include insufficient foam sealing around the frame (creating thermal bridges), incorrect shimming causing hardware misalignment and air gaps, and missing or damaged vapour barriers at the frame-wall junction.
At Tecnisun, the manager takes part in every installation alongside our regular professional installation team, following STRUGAL's official protocol. The profiles carry the manufacturer's warranty, subject to STRUGAL's terms.
Windows alone provide the foundation, but the best results come from a holistic approach. Our most successful projects combine efficient windows with complementary systems:
Replacing your windows in Granada or Malaga is an investment in comfort for many years. Tell us about your home and we will recommend the most efficient solution. Free, no-obligation online quote; the technical home visit has a cost, which we tell you before arranging it.
Request a quote →
Free, no-obligation online quote with your measurements and photos. The technical home visit has a cost, which we tell you before arranging it.