Someone told me that it is bad for the central air system to cover the intake vents with furniture, even though the furniture sits on legs and is not flush with the floor.any ideas or answers?
The only way you can hurt it is if you cause it to freeze up due to lack of air flow. Check the heat exchanger coil and if it does not ice up and block the air, it will not harm the unit.
insufficient return air can be very detrimental. The goal should be not effectively reduce the opening size. So, if the return air opening is 6 x 24, that's a total of 144 square inches. Your furniture should be high enough so that the area directly over the return air opening will provide at least 144 (in the sum of all four sides). If it's a sofa, no matter how large, that sits above the return air opening 3, here's the deal: 24+24+6+6 60 x 3 180 of open space around return air. Now, if the return air opening is against an outside wall and the sofa was pressed against the wall, you have to take on 24 dimension out of the math: 24+6+636 x 3 108 of open area. This may seem like a complex way to answer a simple question, but this is applied in industry all the time and is especially important if you're dealing with forced air heat.
