Hacker News Reader

Comment by kec | Hacker News Reader

This isn't really true. Electric heating is as close to 100% efficient as is practical in the real world. I would also be shocked to learn that gas turbines at a power plant extract fewer watts per unit of gas than a simple (likely poorly maintained) burner in a residential setting.

View on HN

That may be true for stoves where heat goes into the air but it’s not true for other appliances. Most modern gas furnaces have an efficiency of about 80%, meaning 20% of energy is lost as exhaust. Some newer systems have efficiencies as high as 98.5%, and older systems might go as low as 56% [1] Natural gas combined cycle plants (they have have multiple turbines for increased efficiency) around 50% efficiency (efficiency is limited by the thermodynamics of converting heat to electricity) [2]

So even with the worst furnace and the best power plant, the furnace still has similar efficiency. In the average case, furnaces are more efficient.

[1]: https://www.energy.gov/energysaver/furnaces-and-boilers [2]: https://www.sciencedirect.com/topics/engineering/natural-gas...

This is not true since the vast majority of electric whole home heating units sold today are heat pumps, which are up to 300% efficient [1]. If the power generation and distribution is 33% or higher efficiency, then a heat pump will outperform a natural gas furnace operating at 100% efficiency.

EDIT - Here's a video that explains it much better than I could, although it's a bit long, this YouTuber is great. [2]

[1] https://tristate.coop/advantages-heat-pumps-energy-efficienc... [2] https://www.youtube.com/watch?v=MFEHFsO-XSI

The best gas generators are (approx) 60% efficient. Gas furnaces are around 90% efficient.

Electric heat pumps can go up to 300% efficient, and they don't care what kind of power source the grid uses.

Reply on news.ycombinator.com