Yes, it exists. It is not a marketing trick: it is a regulated mechanism that can fund attic insulation. Here is how it actually works, when it comes close to zero cost and when it does not — no small print.
See the official sheet and its calculator (RES022)The “€1” is not an offer: it is the CAE system
You have probably seen adverts for “free” or “€1” attic insulation and rightly assumed something was off. Nobody gives away building work. Yet in many cases the owner pays nothing, or only a symbolic euro. The explanation is not generosity but a market mechanism worth understanding before signing anything.
Since Royal Decree 36/2023, large Spanish energy retailers have a legal obligation to demonstrate each year that they contribute to national energy savings. To comply, they fund real efficiency measures. Each measure generates certificates — CAE — evidencing the savings achieved, and the retailer buys them to meet its obligation.
In one sentence
Insulation can end up at zero cost because an energy company pays for the energy savings your work generates. That payment flows through Energy Savings Certificates (CAE).
- 01
The insulation is installed
An installer insulates the attic and documents the work.
- 02
Certifiable savings are generated
The energy that will no longer be consumed is calculated and the file prepared.
- 03
The owner transfers the CAE
You assign the economic right to the savings in exchange for funding the work.
- 04
The energy company pays
It buys the certificates to meet its quota, so you pay nothing up front.
Why attics are the most favourable case
Not every measure ends at zero cost. Insulating an unconverted attic — the storage space under the roof — is often the best case for three reasons: the work is inexpensive (blown mineral wool or cellulose over the floor, no rubble and usually a single visit), the savings are high because a poorly insulated roof loses a large share of the heat, and the equation adds up when the value of the certifiable savings matches or exceeds the installation cost.
~30%
of heat lost through a poorly insulated roof
1 day
blown-in installation, no building work
20–30%
potential saving on the heating bill
Indicative figures: the real result depends on the home, the climate zone and the starting condition.
When it costs €1 and when it does not
Zero cost is not universal: it depends on the certifiable savings covering the work. These are the deciding factors.
- Unconverted attic. The standard blown-in case and the best fit. If the space is habitable, the technique changes and funding covers less.
- Climate zone C, D or E. The colder the winter, the greater the certifiable savings.
- Older home. The poorer the starting insulation, the larger the improvement and the evidenced savings.
- Enough surface area. Above a certain floor area, the savings generated cover the cost more comfortably.
- When a balance may remain. In milder zones, on small surfaces or borderline cases a residual cost can remain. The honest thing is to say so beforehand.
Warning sign
Be wary of anyone promising a “guaranteed €1” over the phone without seeing your case. Zero cost is real, but it is confirmed after a pre-assessment: attic type, zone, surface and starting condition.
How we work
At CAE Economía we do not sell a promise: we build a file that withstands verification. Before anything is touched we check whether your case fits and what savings can be evidenced. Only then do we tell you your cost — zero, one euro or, where applicable, the real figure.
From there we handle everything: savings calculation under the applicable methodology, evidence (measurements, photographs, material data sheets), documentation and processing through to validation. Our principle is simple: every figure must lead to a supporting document.
Frequently asked questions
- Do I really pay nothing?
- In many eligible cases, no. You assign the economic right to the savings and the work is funded by the CAE. If a balance remains in your case, we tell you in advance.
- Is it messy building work?
- No. Blown-in insulation is projected onto the attic floor, with no rubble and usually in a single visit of a few hours.
- What do I gain beyond funded work?
- A more comfortable home — less cold in winter, less heat in summer — and a lower heating bill year after year.
- Is it compatible with other support?
- CAE is an independent mechanism and can often be combined with other renovation support routes. We check this during the pre-assessment.
- How do I know if my attic is eligible?
- Send us the basics (location, attic type, approximate surface) and we check it. The eligibility check is free and without commitment.