People normally get confused when looking for furnaces as there are a number of varieties. When choosing furnaces, people take into account various aspects like price and efficiency. In the market, one can choose between one stage furnace and two sage furnace.
Though these two furnaces have high efficiency, they are different in many ways. One of the main differences between one stage furnace and two-stage furnace is with regard to the BTU rate. A single stage furnace always runs in full capacity (one BTU) when there is a need for heat. On the other hand, a two-stage furnace runs at a low BTU rate during the first stage. The second stage becomes operational only if the first stage is not able to maintain the required set point. This means that the two-stage furnace uses less fuel than the one stage furnace.
The two-stage furnace can be termed as two separate furnaces. A benefit of the two-stage furnace is that one stage operates during mild winter and another runs during colder winter. But this facility is not available with a single stage furnace as there is only one furnace.
When compared to one stage furnace, the two-stage furnace distributes heat more evenly. Â Moreover, the two-stage furnace operates in a quieter atmosphere in contrast to the one stage furnace.
The two stage furnace runs for a longer time than the one sage furnace. When comparing the two furnaces, the two-stage furnace runs in a lower speed. There is also a consistent flow of heat when using a two sage furnace. The one stage furnace only has a single speed furnace blower whereas the two-stage furnace comes in multi speed furnace blowers.
Summary
- A single stage furnace always runs in full capacity (one BTU) when there is a need for heat. On the other hand, a two-stage furnace runs at a low BTU rate during the first stage. The second stage becomes operational only if the first stage is not able to maintain the required set point.
- A benefit of the two-stage furnace is that one stage operates during mild winter and another runs during colder winter. But this facility is not available with a single stage furnace as there is only one furnace.
- When compared to one stage furnace, the two-stage furnace distributes heat more evenly.
- The two-stage furnace operates in a quieter atmosphere in contrast to the one stage furnace.
Great article! Easy to understand and spelled out very well!
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A single stage 3 ton furnace at rated 96% efficiency is just as efficient as a two stage 3 ton rated at 96% efficiency, by definition. They both waste 4% by definition, no more, no less. To claim otherwise about the furnace is false, correct?
Operating cost would be the same. Capital cost would be less for single stage.
To raise the indoor temperature from one set point to another, a specific amount of heat needs to be transferred. A single stage running 100% pushes out more heat for a shorter period of time, and, a two stage operating at say 80% pushes out less heat for a longer period of time. Once again, by definition of simple math. If the single stage used the same amount of time as a two stage then you would have a case, but it doesn’t so this claim is null.
Blowing at 80% compared to 100% should be no different in ECM noise for both so noise is really determined by air flow through ductwork. A 20% lower air flow won’t make that much difference on average, because the ductwork is design for 100% on the 2 stage anyway. The owner won’t know the difference unless the two different units were swapped inside his specific home and a decibel meter used to measure the difference so this claim is really disingenuous. If it was 50% or less then one could consider the claim.
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