A two-stage variable speed furnace offers a number of advantages for heating a home and can be a smart investment when choosing a new furnace.
What is a 2-stage variable speed furnace?
A variable speed furnace has an electronically commutated motor (ECM). It is a DC motor that is able to achieve greater efficiency than most AC motors. While the initial cost of a furnace with an ECM will be higher than a traditional furnace, the typical payback is four to five years.
How does it work?
The variable speed furnace varies the amount of circulated air, unlike conventional motors that operate at one constant speed. By monitoring data from the heating and cooling system, the furnace adjusts for greater comfort and efficiency of operation. This allows the system to compensate for factors like dirty filters or blocked vents by increasing the fan speed. The majority of the time, the first stage operates running at about 65% capacity. When the temperature drops, the second stage kicks in for added warmth.
What are the key benefits?
1. ECMs are low-maintenance
ECMs cycle on and off much less frequently than single-stage furnaces. As a result, there is much less stress put on the furnace. This means minimal risk of breakdowns and a longer operating life for the system.
2. Energy efficient
Unlike a single-stage furnace that only has a high capacity setting, a two-stage furnace operates the majority of the time at the low capacity stage. Therefore, the system uses much less energy overall, even though it operates more often.
3. Can reduce operating costs
The combination of greater energy efficiency, minimal maintenance, fewer repairs and longer operating life all translates to reduced operating costs over the life of the system.
4. Quieter operation
Another benefit of the two-stage furnace running at low output most of the time, is a great reduction of the operating sounds typically associated with traditional heating systems that constantly cycle on and off through many short, full-blast cycles.
5. More even temperatures (increased comfort)
The consistent operation at the lower output stage (less cycling on and off) means your home maintains a more constant temperature. A single-stage furnace, that blasts your home with a large amount of heat every time the system turns on can create temperature spikes and dips. A two-stage furnace, however, operates longer than a single-stage furnace (and at a lower setting), which allows it to heat your home more consistently and with much smaller temperature fluctuations.
6. Improved indoor air quality
The design of the two-stage furnace with its longer heating cycles sends the circulated air through the system’s filtration devices more often than a single-stage furnace. More particles are removed from the air so your home maintains a higher level of freshly filtered air.
Because a two-stage furnace has longer heating cycles than a single-stage furnace, air is sent through your system’s filtration devices more often. This leads to better air quality because more particles are removed from the air and your home will have a more consistent supply of freshly filtered air.