Thank you @DianeW777 !
It does not seem I can use the De Minimis Safe Harbor as the limit is 2,500K and the HVAC was 8K, if I understood everything correctly.
However I did also have a small water heater replaced in a rental as well that cost 1.5K and I just assumed I could expense it due to the relatively low cost, or it perhaps being considered an appliance. Seems odd that something costing 1.5K would need to get depreciated over 27.5 years. But now I am thinking it should actually be put under the De Minimis Safe Harbor as I believe it would in fact qualify.
