Personal tech blog — energy systems, smart home, urban transport
During the late-June 2026 heatwave we let the sensors run and treated a 40 °C weekend as a thermal stress test. The results: keeping cool cost less than a light bulb, the sun paid for most of it, and the cheapest fix for the hot bedroom isn't an air conditioner.
Real sensor data from a Sendom house near Poznań reveals which ventilation and cooling strategies actually work — from cross-ventilation events to heatwave simulations.
How we built a calibrated six-zone thermal model of a sendom.pl prefab house using Home Assistant sensor data, and what it revealed about insulation quality and HRV efficiency.
I analyzed 365 days of Polish grid data at 15-minute resolution. Poland is already at 46% renewable share — and the data challenges several popular assumptions about intermittency, costs, and the optimal energy mix.