RAM upgrades don't meaningfully increase power or heat.

Not noticeably. The difference between 8GB and 16GB of RAM is maybe 1–3 watts at most — less than a nightlight.

RAM is one of the least power-hungry components in a computer. A single stick of DDR4 pulls about 2–3 watts at idle, maybe 5–6 under load. Doubling the capacity doesn’t double the draw; it might add 1–2 watts. Heat output scales similarly — barely measurable without instruments.

The real power hogs are the CPU and GPU. A background browser tab uses more energy than the RAM difference. Even overclocked RGB RAM isn’t going to move your electricity bill or raise your case temps by a degree.

If you need 16GB, the performance benefit far outweighs the trivial power cost. Don’t overthink it.