Re: Adding Attic Insulation
Tony ... welcome to the forum.
In my opinion your idea is good one and is along the current thinking of providing a "conditioned" space ... if you will ... for the air handler and wouldn't hurt for overall insulation value of the home.
The concept of "conditioned " space for the air handler is by insulating not only the underside of the roof but also all areas of the attic including the gable end walls.
What this does is help regulating the temperature in this area from heat buildup in the summer and very cold temperatures in the winter.
During the summer when the temperature is very hot the air handler during the A/C use is working harder trying to generate the cool air because it is inside a very hot environment .... and it will also create a chance of condensation.
In the winter the same situation will be present .... the heating system would normally be inside a very cold environment trying to generate the heat you require ... also creating a chance of condensation.
So by insulating the attic space will aid in reducing the heat gain / loss inside the attic which will also aid in increasing the performance of your HVAC equipment.
If you can lift up the plywood to add insulation to the ceiling below would also help increasing the comfort of the living space ...... since it is the thermo barrier between the attic and the living space.
Hope this makes sense and helps.
"" an ounce of perception -- a pound of obscure "