2026 ratios by item
| Item | Indicative range 2026 |
|---|---|
| External wall insulation, SATE, with standard EPS (6 cm) | €55 – 95/m² of façade |
| High-performance SATE (mineral wool or greater thickness) | €90 – 150/m² of façade |
| Roof insulation | €40 – 90/m² of roof |
| Window replacement (PVC or thermally broken aluminium, low-emissivity glazing) | €350 – 700 per m² of opening |
| Air-to-water heat pump for a home (equipment and installation) | €8,000 – 15,000 per single-family home |
| Ventilation with heat recovery | €3,000 – 7,000 per dwelling |
SATE ratios are expressed per m² of treated façade and window ratios per m² of opening: translating them into cost per m² of dwelling requires knowing the real areas of each element, and that step is where most framing errors occur. Measuring façades and openings is prior work, not an estimate proportional to the built area.
Ratios by intervention package
Expressed per built m² of dwelling, for a typical residential building from the 1960s-80s:
| Package | Content | Order of magnitude |
|---|---|---|
| Basic envelope | Standard SATE plus roof | €90 – 160/m² |
| Complete envelope | Adds window replacement | €160 – 280/m² |
| Full energy renovation | Adds heat pump or efficient centralised system and ventilation | €250 – 450/m² |
The jump between packages is not linear in savings: the envelope reduces demand, the systems reduce consumption per unit of demand, and the correct order (demand first, systems second) avoids oversizing equipment that is paid for twice. The correct sequence also reduces the installed capacity and with it the cost of the equipment.
Subsidies and payback
The current energy renovation subsidy programmes (European funds managed by the regional governments, plus tax deductions for efficiency improvement) can cover a substantial fraction of the cost when demand or consumption reductions are evidenced through before-and-after energy certificates. The amounts, percentages and conditions vary by programme, by region and by call, and they evolve: the specific figure must be checked in the call applicable at the time of the project. What is stable is the mechanism: without before-and-after certificates and a technical justification of the saving, there is no subsidy, so the project must be conceived from the outset with that traceability.
In payback terms, envelope interventions show long periods but improve comfort and asset value immediately; systems interventions show shorter paybacks dependent on energy prices. The joint cost-subsidy-saving analysis per package is the useful decision format for homeowner communities.
The essentials
Energy renovation sits in 2026 between €90 and €450 per built m² depending on the package, with SATE between €55 and €150/m² of façade and windows between €350 and €700/m² of opening. The correct method budgets by packages, respects the demand-then-systems order and builds from the start the certificate traceability that subsidies require. For interventions combining energy with layout changes and finishes, the framework is full renovation; for the highest efficiency standard in new construction, the reference is the passive house.
Note: indicative ranges for Spain in 2026, variable by region, building and market. Subsidy programme conditions must be checked in the current call.