1. Read the three ratings separately
Each scale runs from A to G and describes a different characteristic. The envelope rating concerns thermal protection, including walls, roof, windows and floors. Overall efficiency also considers systems and energy sources, including on-site electricity generation. The CO₂ scale covers direct heating and hot-water emissions. A favourable rating does not mean zero life-cycle emissions.
2. Have the PV calculation explained
Give the expert the layout, capacity, orientation, shading and generation forecast. Ask how current rules treat generation, self-consumption and surplus. Panels alone are not insulation; associated roof work can have a separate effect. Do not infer the final rating from panel count or a general percentage reduction in grid purchases.
3. Compare heating, the envelope and energy use
Request options with their input data and reference conditions. Heating replacement and envelope renovation affect different parts of the assessment. For a heat pump, request heat demand and seasonal performance rather than applying a fixed electricity-to-heat ratio. Compare monthly profiles too: annual solar generation does not establish winter self-sufficiency.
4. Define the CECB or CECB Plus service
CECB Plus adds an advisory report with renovation options. Request a quote specifying the visit, records, calculations, options and explanations provided. Check whether an existing certificate remains valid after building alterations. Assume neither one national price nor an identical net cost after grants for every project.
5. Separate the rating from financial decisions
Compare work quotations, confirmed grants, future costs and calculated building-specific savings. Check renovation programmes and PV procedures separately; the report is not a grant approval. A better rating guarantees neither resale price nor loan terms. Keep the dated assessment, assumptions, each option’s cost and contractor commitments for your decision.