Single-Stage vs Two-Stage Furnaces

When replacing a furnace, you may be asked to choose between single-stage and two-stage equipment. The difference is fairly simple: a single-stage furnace has one heating output, while a two-stage furnace can operate at a lower or higher output depending on how much heat your home needs. 

Both can heat an Edmonton home effectively. The better choice depends on your budget, the size and heating requirements of your house and how much you value features such as longer heating cycles and more consistent temperatures. 

How Single-Stage vs Two-Stage Furnaces Work 

A single-stage furnace operates at full heating output whenever the thermostat calls for heat. Once the house reaches the set temperature, the furnace shuts off. There is no lower heating stage. 

That straightforward operation is one reason single-stage furnaces are generally less expensive than comparable two-stage models. For homeowners mainly concerned with replacing an old furnace with reliable equipment at a lower upfront cost, a single-stage model may be a practical choice. 

A two-stage furnace has two levels of heat output. It can run at its lower stage when the home only needs a moderate amount of heat, then switch to its higher stage when heating demand increases. 

This can be useful during an Edmonton heating season. A home may need relatively little heat on a mild autumn afternoon but substantially more during a January cold snap. Instead of operating at full output every time, a two-stage furnace can adjust between its two settings. 

Two-stage operation should not be confused with a variable-speed blower. Furnace stages refer to heating output. Blower speed refers to how air is circulated through the home. Depending on the equipment, a furnace can combine different heating and blower technologies. 

What Difference Will You Notice? 

The biggest difference between single-stage vs two-stage furnaces is often how the heat feels. 

A single-stage furnace delivers its full heating output each time it runs. You may notice more distinct periods when the furnace is running followed by periods when it is off. 

A two-stage furnace can spend longer periods operating at its lower setting when full output is unnecessary. These longer cycles may help maintain more even indoor temperatures and can be quieter when the equipment is operating at its lower output. 

Neither option, however, will compensate for a furnace that is improperly sized. Installing a furnace with more heating capacity than the house requires can lead to short cycling, where the furnace heats the home quickly, shuts down and starts again soon afterward. Ductwork and airflow problems can also contribute to rooms that remain too hot or too cold regardless of the furnace stage. 

This is why we look at the home rather than recommending equipment based solely on furnace specifications. 

Choosing the Right Furnace for Your Home 

Price is one consideration. Two-stage equipment typically costs more upfront than a comparable single-stage furnace because of its additional controls and operating capability. 

Efficiency should be considered separately. A furnace being two-stage does not automatically make it more efficient than every single-stage model. Check the AFUE rating of the specific equipment when comparing options, along with warranty coverage, blower technology and installation requirements. 

Your existing thermostat and ductwork should also be considered. Depending on the furnace selected, thermostat changes or adjustments near the furnace may be required for the new system to operate as intended. 

If your current furnace needs replacing, Hydro-Flo can assess your home and explain the differences between suitable models without selling you features you do not need. Learn more about our furnace installation in Edmonton and talk to us about the right equipment for your home.