New Roof Done but have a question

[06Honda]

We had our one level bungalow home reshingled and they did d really good job. The roofer added a few more vents as there were not many up there when the house was originally built 14 years ago. On humid days I have noticed the house is alot cooler, is this do to the extra vents. Last year the house would have been much more sticky/humid during hot spells. For me this is a good thing physically, just wondering if adding vents would have this effect. They added 4 vents more total.

Paul

[pushkins]

The simple answer is yes, vents will/do reduce attic temps, however there are a few more things that go into a roof vent working as it should, you can put 10 vents in a roof and have no appreciable difference in ventilation, there must be an airflow path into the attic. Typically soffit vents (low on the eaves) allow air to be drawn into the attic then the roof vents allow the air to pass out. The secret here is that for every 150 square foot of attic space there should be 1 square foot of ventilation space (hole). So to look at an example a 1500 square foot house needs (by code) 10 square feet of ventilation. Another condition that is very important is intake air usually represented by soffit vents, if you have 10 square feet of roof vent (holes) you must have 10 square feet of soffit vent (holes) to allow the free flow of air into and out of the attic space, think of it like drinking through a straw and a small piece of ice blocks the straw it becomes instantly harder to draw in.
If your noticing immediate cooler temperatures in the attic from the added roof vents then it sounds like you had plenty of soffit vents and not enough exit air space.

Not only does a cooler attic save you money on heating and cooling your home a cooler attic helps preserve shingle life.

[06Honda]

Thanks for the very informative response, appreciate that. Good to know, the roofer must have known his stuff as it helped for sure. The original shingles were black in colour and starting to curl. The reshingle we used Timberline Architecture shingles, much lighter colour.

Paul