Temperature, Relative Humidity, Dew Point, and Condensation on Windows
A quick background to give you context. The 1867 sq. ft. (basement included) semi detach house was built in 2009 as part of a new large subdivision by a big developer in the west end of Ottawa. The house is a basic 2×6 wood frame, R-20 bat insulation, vinyl siding, natural gas furnace, no HRV and solid wood exterior doors. We keep the house temperature at 15°C (60°F) at night and during the day it’s at 20°C (68°F).
We have been seeing moisture build up on the windows since the first winter but the builder simply said it was moisture due to new construction. Before we moved in, we had bought a stand-alone dehumidifier that run almost year around in the living area in the basement and have it set at 45%.
We run the fans in the bathrooms 15-30 minutes after showering on a timer and the hood fan is running while we cook the majority of the time. When the weather is around 0°C (32°F), I will often open the door/windows to air out the house for 3-5 minutes but that only happens maybe once a month due to our cold Canadian winters.
This year I have decided to get rid of some of the plant I had in the house and only give them a tiny bit of water once every two weeks. This seems to have help reduce the amount of moisture that pools up at the base of the windows when the weather is between -1°C and -12°C (32°F – 10°F). The hygrometer in the kitchen island has been around 30% and the dehumidifier in the basement has been showing in the low 30% since Christmas.
On Sunday February 9, 2020 we had a very cold snap come though the Ottawa Canada area and at around 8:00am the temperature at -25°C (-13°F) and feeling like -31°C (-24°F). When we get cold weather around -20°C or colder, there will be ice forming on just about all of the windows.
After leaving in the house for ten years and reading a ridiculous amount on the subject, I believe on have narrowed it down to two issues; no HRV/ERV and cheap windows with low U-factor.
Anyone else have any thought?
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