A 100 W continuous load would represent almost 15% of my electricity usage. An average US household uses ~1215 W averaged across a year[0], so 100 W is ~8%, which I'd say is still pretty significant. A more power hungry CPU like a Ryzen 9 7950X (170 W TDP) would be almost a quarter of my electricity consumption at full power (and if you use more energy for AC than heating, then it'll add additional load to keep your home at the temperature you want).
[0] https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 (10,632 kWh / year ~= 1215 W average)