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    Construction Performance Guidelines

About the Guidelines

These helpful guidelines outline work and material deficiencies in new homes and residential condominium units covered under the statutory warranty [...]

Condensation On Window Systems

Article Number




Acceptable Performance/Condition

Condensation on the interior surfaces of window systems is not warranted unless it is clearly determined to result from workmanship related to the construction or non-compliance with the Ontario Building Code, the design or the manufacturer’s installation guidelines


One-Year -Work and Materials. Damage caused by dampness or condensation due to failure by the homeowner to maintain adequate ventilation or proper operation of moisture-producing devices such as humidifiers is excluded from warranty.


Windows not meeting the acceptable performance criteria shall be repaired.


Condensation can be a result of lifestyle. Condensation occurs when water vapour in indoor air contacts cool surfaces such as window glass. Condensation on interior window surfaces is common during cold seasons. When outdoor temperatures are well below freezing, ice may form on the window. Since it is important for homeowners to maintain proper humidity levels within the home to prevent damage to other components such as hardwood flooring and for physical health, some condensation on windows may be expected. Indoor humidity levels may be controlled by de-humidification, ventilation or air conditioning. Interior air moving over the windows can help control condensation. Heavy draperies or window coverings that cover windows and blocked heat diffusers can prevent this from happening. Running the ventilation fan continuously can also help to control condensation on windows.