Cooling an Attic with Soffit Vents
How much of a difference will additional soffit vents make for cooling our attic? We live in a 1950’s 1960 sq. ft. 2 story house in Saskatoon, Canada which has a cold semi-arid climate with warm summers (getting hotter) and cold winters. We have no AC but have successfully (until now) used closed blinds during the day and open windows in the evening to cool our house.
Recently we have had unusually hot weather spells and have not been able to rely on cool evenings to cool our house. I poked my head in the attic and it was hot and there did not seem to be much air movement. Ten years ago, I air sealed and insulated the attic with 22 inches of loose fill pink fiberglass. I also added draft stops and air chutes in each rafter bay. Unfortunately, I also discovered that my vented aluminum soffits were covering the original solid wood soffits. The only attic ventilation was coming from two small gable vents and four roof vents. I added 4 soffit vents to increase attic ventilation and prevent ice dams until all the soffits could be renovated in the future. We have not had any ice dams since these four soffit vents were installed. I had not been concerned about completing this job until now. Removing the solid wood soffits on a 2 story house and replacing them with vented soffits would come at a price. I would be willing to pay it if it would significantly help to keep our house cooler, but I’m concerned that this might be money wasted. Any advice as to if this ventilated soffit reno would help with our overall house cooling would be appreciated.
As added information our Blower door results after the attic air sealing and other improvements was 1000CFM @ 50 Pa. To the best of my knowledge our wall construction is stucco, tar paper, 1 ½ inches EPS, ½” ship lathe, 3 ½ inches mineral wool, rock board and three skims of plaster.
Thank you in advance for your help,
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