Power meter and heat-flow diagram for a homelab rack Power meter and heat-flow diagram for a homelab rack

Watts, BTUs, and the real cost of running a homelab 24/7

TL;DR A homelab feels free until you read the meter. After a year of running seven k3s nodes plus a pair of Mac Studios under whatever workload I felt like throwing at them, I sat down with a Kill-a-Watt and worked out what the cluster actually costs to keep on. Idle is genuinely cheap. Sustained LLM inference is not. The honest break-even against cloud inference is workload-shaped, and for my workloads, on-prem wins — but only because I run them often enough to amortize the wattage. The numbers below are mine; substitute your electricity rate to get yours. ...

May 14, 2026 · 7 min · zolty
Two Mac Studios bridged by Thunderbolt 5 running a 1T parameter MoE Two Mac Studios bridged by Thunderbolt 5 running a 1T parameter MoE

Running a 1T-parameter MoE locally on two Mac Studios over Thunderbolt 5

TL;DR Two M3 Ultra Mac Studios — 256GB unified memory each — connected by a Thunderbolt 5 cable can run mixture-of-experts models in the trillion-parameter range that no single 256GB box can fit. The hot path stays on Box 1; Box 2 hosts heavier experts and gets called via a local nginx proxy on port 11436. Real-world power draw is nowhere near the spec sheet. Some models still don’t fit even with two boxes (Kimi K2.6 native INT4), and that’s a genuinely useful constraint to know. ...

May 6, 2026 · 6 min · zolty

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