1.   Another problem with tankless heaters, Gifford said, is that they typically require a larger vent hole than the tank-type heaters they often replace.

2.   Berry said that radiator valves come with different-sized vent holes that allow for fine-tuning a heating system.

3.   By blocking the vent holes you can do more than ruin your monitor.

4.   Carefully make a vent hole in raft with spoon handle.

5.   Check the tops of recessed lights and attic vent holes.

6.   Cut a piece of plywood to a size that will accommodate the attic framing that surrounds the vent hole.

7.   Cut vent holes in the center.

8.   Cut vent holes in the top.

9.   Next, measure the openings of the vent holes, including soffit and roof vents.

10.   That can block vent holes.