Installing the NF-A15 wasn’t as hard as we thought. Our initial reaction to the frame was soon followed by a quick visit to the Noctua website, more specifically: HERE, where we found some guides for installing the A15 into our NH-D14. We didn’t have any clearance issues in our Fractal Define R3.
“The NF-A15 is fully compatible with the NH-U12P, NH-C12P and NH-C12P SE14. On the NH-D14, the NF-A15 fan can only be installed upright, which increases the total height of the cooler by 8mm. Please thus note that in order to use the NF-A15 on your NH-D14 cooler, you need to have at least 8mm of additional clearance above the heatpipe tips:”
The A15 is also compatible with the Noctua NH-C14 although you will need to slightly off set the bottom fan so it isn’t a perfect fit.