Use an energy assessment before renovation

Why assess before changing insulation, windows or heating

The largest visible problem is not always the largest heat-loss path. A roof, wall, floor, window, thermal bridge, uncontrolled air path or heating-control issue can affect the result differently. Recording the existing building first makes the uncertainty visible before a specification or quotation is chosen.

Envelope measures should be assessed with ventilation and heating. Better insulation and airtightness can reduce heating demand, alter surface temperatures and make a deliberate ventilation approach more important. Heating-system sizing and control should be reviewed after the envelope strategy is clearer.

A practical renovation decision framework

Use the assessment as a sequence for asking better questions, not as a replacement for professional design.

• Step 1: describe the existing building—areas, layers, openings, heating, ventilation, climate and available consumption.
• Step 2: identify the largest estimated loss contributions and the least certain inputs.
• Step 3: compare individual renovation measures using consistent assumptions.
• Step 4: check moisture, condensation and ventilation implications before changing the envelope.
• Step 5: compare combined scenarios, including the effect on heating demand and system choices.
• Step 6: use the documented assumptions to prepare a renovation brief, survey request or professional design discussion.

Condensation and moisture require more than a U-value

The application provides a simplified condensation-related indicator from entered layers and assumed indoor and outdoor temperatures. It is useful for flagging a question, but it is not a hygrothermal simulation, a relative-humidity model or confirmation that condensation will occur.

Insulation can improve interior surface temperatures, but moisture safety also depends on layer order, vapour control, rain exposure, thermal bridges, airtightness, ventilation and workmanship. Seek detailed moisture design where the construction or consequence warrants it.

Use scenarios to plan a system, not a product list

Compare combined measures when they interact: roof insulation with ventilation, window replacement with airtightness, or envelope improvements with heating-system capacity. The report can organise these questions, while detailed sizing, junction design and installation specifications remain professional design tasks.

Assess before renovation

Create a preliminary building record before selecting renovation measures.