Talk:Forced-air

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Engineering

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AFUE? Sounds nasty![edit]

What is "90%+AFUE" in the Advantages paragraph? What does that mean? N3362 05:36, 16 July 2006 (UTC)[reply]

AFUE = annual fuel utilization efficiency. It refers to the percentage of heat from the fuel delivered to the heated space relative to the input. So for example 80% implies that 20% of the heat produced goes up the exhaust stack. —The preceding unsigned comment was added by 65.94.132.32 (talk • contribs) .

Advantages/disadvantages section[edit]

This section is highly ambiguous as it's attempting a comparison without explicitly stating what it's comparing anywhere. There are four or five different systems described here, and nowhere is it stated which ones are being compared, or what they are collectively being compared to. AeoniosHaplo 10:34, 20 March 2007 (UTC)[reply]

This is Wikipedia, so you know what to do: be bold and help improve the article!

I clarified it. (original author)

Atlant 11:47, 20 March 2007 (UTC)[reply]

Effectiveness not mentioned in article[edit]

Scientific fact, common knowledge in the industry: As air does not store heat as well as liquids like water do, this kind of heating is ridiculously ineffective. Because of high energy consumption and thus permanently higher costs just to operate such a system it is not worth it. Combined with non-insulated walls and ceilings and technically outdated single-pane windows, the loss of the heat energy is massive. Unless you live in a Koeppen scale BWh desert. — Preceding unsigned comment added by 2003:8C:4C3D:4F00:F94D:4458:30CE:B53A (talk) 14:51, 16 November 2017 (UTC)[reply]

This is non-sense; heat losses being constant, total energy consumption of a heating system is not determined by the specific heat of it's heat transfer medium such as air, it's determined by energy output vs energy input.

Whether water is heated and the heat is transferred to the air via contacting the radiator or surfaces radiantly warmed by the rad or the air is directly heated, it doesn't make a lick of difference.

When the specific heat of a substance is lower, lets say air is lower than water, you just need a higher mass flow rate to deliver the same amount of heat.

Yes, the blowers in forced air systems use more electricity than circulator pumps in hot water systems.

But the efficiency (that is, energy consumed vs total heat delivered) is the same if not higher on forced air than other systems.

Little known fact; condensing hydronic boilers rarely deliver over 85% efficiency despite being rated at 90%+. The return water temperature has to be low to facilitate enough heat transfer to get into the 90s, necessitating the use of an outdoor reset control and lower water temps.

The condensing furnace has room temperature air hitting it's secondary heat exchanger so the heat transfer is always very good - new condensing furnace can achieve 96%+ efficiency in all operating conditions.

At typical aqua stat setting - 180f, the return temp often won't be much lower than 140f. You need 120f water to for the boiler to even start condensing and delivering over 88% efficiency. — Preceding unsigned comment added by 157.52.8.100 (talk) 07:02, 17 December 2017 (UTC)[reply]

If hydronic heating is less efficient, why does it "predominate in Europe" (as the article claims)? 174.24.0.143 (talk) 01:40, 12 February 2018 (UTC)[reply]