Yup @rev.hodl said something along those lines
https://bitcoinnews.com/mining/households-bitcoin-heater/#:~:text=When%20using%20a%20Bitcoin%20miner%20to%20both%20hash%20and%20do%20work%2C%20any%20electrical%20heat%20source%20that%20does%20not%20hash%20is%2C%20therefore%2C%20less%20efficient%20because%20it%20is%20using%20the%20power%20for%20fewer%20functions%20than%20a%20Bitcoin%20miner%20in%20the%20same%20situation.
