We recently had spray in foam insulation put under the roof of our ICF house, completing the insulated building envelope. Although the exterior temps have been 90-100 degrees F, inside the house, with no AC has been 10-15 degrees cooler than the outside. I can't help but think that will translate to lower HVAC needs. I did not see the actual calculations, but I know the HVAC for our new 2778 sq. ft. house is not a whole lot bigger than we have in our current 1680 sq. ft. one. Insulation is not the whole story - a well sealed building envelope will make a lot of difference in the comfort level and HVAC use.

It's a modular. I already asked the company about making one wall deeper but they said they can't. Our township required our present home on the same lot to be demolished within I year after we received a permit for the new home. No builder could guarantee one could be finished in that amount of time so we went with a modular. We're living in the home that will be demolished and it was out of the question to move somewhere else during the build. Too much stuff and too many animals. Halfway through the project the township removed the code. It was too late to back out. My nephew has a modular that is very nice. Very well built. We ran into several limitations in designing it however. This being one of them.

Thanks everyone for the thoughts and ideas. We have two systems, one for each floor. The upstairs has two returns and the downstairs has just this one. I assume for the purposes of your question that means that this is the only return, since the systems operate separately. We will definitely account for being able to check/change the filter without having to move the furniture every time - with the furniture only ~1" higher than the top of the grille, I only need a few inches behind the furniture to be able to open the hinged grille and pull out the filter. Do you think a perforated back (wood or metal) would be a reasonable compromise? For example, if we need 5"-6" clearance behind the bookcase if the furniture has a solid back, would we be able to get away with 3"-4" if the back allows for some airflow? We'll need at least 3" to be able to change the filter as I described. Thanks again!

I think centering it will give it too much importance. In a grouping of other art or shelves, it can be made to take second place to more impactful pieces. I really like the reclaimed wood example you showed above. Here's another idea, since your style is farmhouse. You could attach a 2'x2' tin ceiling tile to the front of the unit and attach three more tin tiles to frames with depth the same as the closed unit. Hang them so there is one piece to the right of the unit and two to the left. Then add a long buffet or shelf under them. You could also try 2x4 tiles hung vertically so the bottom of the arrangement is nearer a buffet or shelf, but the bottom might hit the wall when the unit opens. If you like that look better and it does hit, you could move it up a bit so the top edge of the tile is a few inches above the top edge of the unit. I'd try Command strip. https://www.overstock.com/Home-Garden/Great-Lakes-Tin-Jamestown-Vintage-Bronze-2-foot-x-2-foot-Nail-up-Ceiling-Tile-Carton-of-5/10664456/product.html?refccid=442GC3D25ZKJUY2M6BJCCTAVDI&searchidx=29