Understand the distinction
One room may feel different from another at particular times of day. An observation such as “cooler beside this window this morning” is more precise than declaring an insulation defect from one experience. Duration, weather and room use provide useful context.
Put it in your home notes
Record location, date and the ordinary conditions you observed. Do not open building elements, vents or equipment to investigate. Share recurring concerns with an appropriately qualified assessor, keeping the distinction between an observation and a technical diagnosis clear.