Heat can leave through an attic by passing through the ceiling and insulation or by moving with air through gaps in the ceiling. A thin or uneven layer can make the first problem worse. An unsealed hatch or opening can make the second worse. You need information about both to estimate attic heat loss.
Start with an attic inventory
From a safe access point, look for insulation depth that varies across the attic, bare areas along the perimeter, and gaps at the hatch. Note whether the attic has ducts and whether the insulation lies on the ceiling or along the roof deck. Photographs can help a contractor identify the configuration without guessing.
Use measurements to narrow the estimate
A home energy assessment can look at the area and insulation levels of the attic and assess air leakage. Infrared imaging can show unusual temperature patterns when conditions are suitable. A blower door can help identify air leaks, but a whole-house reading by itself does not tell you exactly how much heat goes through the attic.
Ask how the proposal handles coverage and leaks
Have the contractor identify the current insulation boundary, the gaps that will be sealed, and the planned insulation level. Ask how the work will maintain ventilation where required and deal with electrical fixtures or other heat sources. An estimate is more useful when it explains what will be done in each part of the attic.
Provide the details that affect the scope
When you request a quote, include the access type, approximate attic size, and any spots you have seen with low or missing insulation. If you have energy assessment results, mention them so the proposed work can be tied to those findings.
