Talks to Watch

Forced-air Furnaces: The What, Why, and How

1.8M views · Oct 10, 2020 · 22:05 · 2 HN recommenders · 6 mentions · discussed 2021–2026

Technology Connections explains what forced-air furnaces are, how they work and why they need electricity. He covers combustion, airflow and the parts of a modern furnace.

Why Hacker News points people here: HN people point to it as the full explanation of how gas furnaces work, mostly in threads on heating, power outages and gas appliances.

“For a full on description of how a good portion of furnaces, tech connections made a video not long ago”HN comment, 2021

What Hacker News said 6

Recommends8noteFeb 2021

“For a full on description of how a good portion of furnaces, tech connections made a video not long ago”

Full description of how furnaces work.

Full comment

For a full on description of how a good portion of furnaces, tech connections made a video not long ago: this video

in “What went wrong with the Texas power grid?” · view on HN
Recommendsthrow0101aFeb 2021

Good overview of forced-air furnaces needing electricity.

Full comment

Yes, they do need need electricity. Source: I live in Ontario, Canada, and am currently being kept warm by one. Most (gas) furnaces are forced air, and how exactly would the fan run without electricity? How do you think the thermostat runs its thermistor (and probably LCD display) without a power? The Technology Connections YT channel has a recent good overview, "Forced-air Furnaces: The What, Why, and How": * this video As for efficiency, you can get units that are 99% efficient (AFUE): * link * link

in “Analysis: Texas power outage leaves officials working political angles” · view on HN
Recommends8noteMay 2022

“Tech connections has what you're looking for”

Covers what the asker is looking for about furnaces.

Full comment

Tech connections has what you're looking for: this video Efficiency wise, the comparison between a heat pump and a furnace depends on the outside temperature. Heat pumps lose their efficiency for high ∆T, so for winter in a Russia, a furnace is likely the better option

in “SEC charges Nvidia with inadequate disclosures about impact of cryptomining” · view on HN
Cites itCaliforniaKarlJun 2022

Shows modern furnaces use outside air for combustion.

Full comment

Modern gas furnaces use the outside atmosphere for combustion. It helps get them high (for gas) efficiency levels! this video

in “What a gas stove ban means for restaurants” · view on HN
Cites itthrow0101cFeb 2023

Shows condensing furnaces are sealed off from the house.

Full comment

> It's not supposed to be sealed, it's just supposed to have draft. It depends on the model. High (>90%) efficiency, condensing furnaces are completely sealed off from the house: they take in air from the outside (via PVC pipe), combust, extract the heat, and exhaust the results (via PVC pipes). * this video Older lower efficiency (<85-90%) furnaces suck in air from the house, exhaust into metal pipes (PVC would melt because not as much heat is extracted from the fumes), can be back-drafted and you have to worry about CO. Basically: if the furnace has vents in which you can see a pilot light, it's the older style.

in “I Bought a CO2 Monitor, and It Broke Me” · view on HN
Cites itfhdkweigAug 2026

“Technology Connections did a video (because of course he did) on how gas furnaces work.”

Explains the flame is contained and never mixes with indoor air.

Full comment

Technology Connections did a video (because of course he did) on how gas furnaces work. The short of it is that the flame is contained inside of metal tubes and never mixes with indoor air. No exhaust gases can leak into the breathable air. this video

in “Switching to electric stoves can dramatically cut indoor air pollution” · view on HN