Roskilde, Denmark – from dehumidifier to heat-recovery ventilation
An indoor-climate case illustrating the difference between removing moisture from air with a dehumidifier and establishing controlled air exchange.
Denmark · RoskildeBASEMENTATLAS · Europe
Basement ventilation & condensation
Ventilation manages airborne moisture and pollutants; it does not stop liquid water through a wall or floor. In summer, more outdoor air can even increase condensation when the outdoor dew point is above the temperature of cold basement surfaces.
basement ventilationsummer condensation in basementsheat-recovery ventilation in basementshumidity-controlled basement ventilation
What matters before choosing a solution
- Describe when the problem appears and where it is strongest.
- Include building age, ground conditions and photos inside and outside.
- Separate the symptom from the suspected cause and report what was tried.
Have you already completed a similar project? Share the method and the result so others can compare outcomes.
BASEMENT ATLAS
Sources and evidence
Source types stay separate: technical and authority-adjacent sources support rules and risk topics, while project sources document practical experience.
2 technical/authority sourcesUpdated 2026-09-08
Assessment
Basement ventilation & condensation
Ventilation manages airborne moisture and pollutants; it does not stop liquid water through a wall or floor. In summer, more outdoor air can even increase condensation when the outdoor dew point is above the temperature of cold basement surfaces.
1Record ventilation type, operating hours, extract/supply locations and indoor humidity before changing equipment or airflow rates.2Measure room temperature and relative humidity and compare them with the temperature of the suspect surface, especially during warm humid weather.3Define the intended use, heating level, occupancy and moisture production before choosing insulation, ventilation or finishes.4Find service history, clean or inspect accessible components and distinguish a maintenance failure from an undersized or incorrectly designed system.
BASEMENTATLAS · SEARCH INTENT
Start with the problem closest to yours
These paths lead to existing guides, scenarios, checklists and comparisons, not artificial keyword pages.
GuideBasement ventilation or a dehumidifier: choose by the problem→GuideBasement condensation in summer: when opening windows adds moisture→Problem scenarioBasement humidity is high only in summer→ComparisonVentilation vs Dehumidifier→GuideHeat-recovery ventilation in basements→GuideHumidity-controlled basement ventilation→GuideBasement indoor air quality→ChecklistBasement ventilation installation checklist→
BASEMENTATLAS · Evidence & moderation
Evidence & moderation
BASEMENT ATLAS
Continue in the same topic
Related guides, problems, checklists, cases and technical terms from the same knowledge area.
GuideBasement condensation in summer: when opening windows adds moisture→GuideBasement indoor air quality→GuideBasement ventilation or a dehumidifier: choose by the problem→ScenarioVentilation makes the basement wetter in summer→ChecklistBasement ventilation installation checklist→ScenarioBasement humidity is high only in summer→ScenarioCondensation forms on cold pipes in the basement→CaseBagsværd, Denmark – heat-recovery ventilation in a basement→CaseHolbæk, Denmark – basement ventilation through a lightwell→CaseRoskilde, Denmark – from dehumidifier to heat-recovery ventilation→ProblemCondensation / summer damp→ProblemMould or black spots→
Problem guide
BASEMENTATLAS · Problem finder
Key signals to document
AllDamp basement & water ingressMould in basement & musty odourBasement ventilation & condensationBasement drainage & exterior waterproofingBasement excavation & lowering the floorUnderpinning & foundation strengtheningBasement floor, insulation & underfloor heatingRadon in basementBasement bathroom, drainage & waterproofingBasement windows, daylight & exterior exitsBasement walls, insulation & finishes
BASEMENTATLAS · Knowledge map
Problem guide
Guides
Comparisons
Problem scenarios
Checklists
Holbæk, Denmark – basement ventilation through a lightwell
A specialist basement ventilation case where below-ground level and the lightwell dictated a non-standard installation detail.
Denmark · Holbæk
Bagsværd, Denmark – heat-recovery ventilation in a basement
A documented heat-recovery ventilation installation showing wall drilling, placement and the completed unit in a basement.
Denmark · Bagsværd