Stat Climate

Early Bird Sale: Save 20% on your AC + Free Bonuses

Furnace Types

About Single Stage, Dual Stage and Modulating Furnaces

When it comes time to buy a new furnace there are some important factors to consider before deciding what is best for your needs.

It’s important to consider the 3 types of furnaces and the advantages and disadvantages that they each offer.

Single Stage Furnace

Also known as a Single Speed Furnace, has 2 settings – Off and On (or 1 stage of high heat output).

How It Works

When the thermostat drops and there is a call for heat the burner turns on at full capacity warming the air before being sent throughout the home by the blower. Once the thermostat temperature setting has been reached the burners shut off.


  • A single stage furnace is the most affordable type of furnace and usually a popular choice for budget conscious consumers.
  • A good alternative if you aren’t planning to keep the home for 10 years or more.


  • Less energy efficient than 2 stage or modulating furnace types.
  • May provide inconsistent heat during colder days as it may feel cold between heating cycles (when the furnace shuts off after reaching thermostat setting). This inconsistent heating effect may be exacerbated if your thermostat is improperly placed too close to a heat register (which warms up faster than other areas of your home).

Bottom Line

If your home already has a single stage furnace and provides adequate heating comfort during Calgary’s cold winter days and your heating bills aren’t outrageous then a single stage furnace would be all you need.

Two Stage Furnace

Also known as Dual Stage Furnace, has 3 settings – Off, Low Mode and High Mode.

How It Works

The first stage of heat (low mode) is the setting which is used for most cool to cold days. During the coldest days of winter the second stage of heat (high mode) kicks in to provide maximum heat.


  • A two stage furnace is more efficient than a single stage furnace as the slower heating cycles (low mode) require less energy.
  • A two stage furnace is also quieter than a single stage furnace.
  • Longer heating cycles provide more consistent heat and less temperature fluctuations in the home because of reduced time periods of the furnace not running as is the case of a single stage furnace.
  • Provides better heat distribution, with slower heating cycles, in two story homes or for homes with more than 2 levels.
  • Because the furnace runs longer pushing the air through the HVAC system more pollutants and unwanted airborne particulates are filtered out – increasing indoor air quality. This will also improve humidity for homes with whole house humidifiers.

A dual stage furnace is an excellent option if you want more consistent heat with less temperature fluctuations than a single stage furnace, and you don’t want to spend more for the top of the line modulating furnace.


  • A two stage furnace costs a few hundred dollars more than a single stage furnace but it will reduce energy cost.

Bottom Line

If you plan on staying in your home for 10 years or more, have more than a 1 level home and want to reduce energy cost a dual stage furnace is an investment worth considering.

Modulating Furnace

Also known as a variable speed furnace has almost infinite settings for precise heat delivery.

How It Works

It will generally run (near) continually at very low speeds, to maintain the temperature, but will also provide comfortable heat throughout your home on the coldest winter days.


  • The temperature fluctuation is minimal as the furnace can maintain the desired temperature in your home by as little as just a few degrees.
  • The heat delivered in the home is even and consistent, continually flowing unlike other furnace types which cycle on, blasting heat and then shutting down. The blower can run at very slow speeds to maximum output when needed.
  • This type of furnace provides maximum efficiency, up to 98% AFUE, which means a mere 2% of fuel is unused.
  • With a variable speed motor you will greatly reduce electricity usage.
  • Near continuous air movement will cycle more air through the system improving indoor air quality. This will also improve humidity levels in winter for homes with whole house humidifiers.
  • Maximized air movement will remove excess humidity in the summer for homes with air conditioning.
  • Variable speed furnaces are very quiet compared to other furnaces with single speed motors.

A modulating furnace is an excellent option if you have the budget and a home where you want better temperature control without temperature fluctuations. These are also the most energy efficient furnaces in the marketplace and as we live in a cold winter climate region, it will help you reduce energy costs.


  • As one would expect the only downside to a furnace designed with the precision and features a modulating furnace offers is the cost.

Bottom Line

If your furnace is costing too much money in energy – this furnace is the best choice for efficiency. If your furnace does not maintain even, consistent heat – this furnace will provide outstanding comfort. If you plan on living in your home for 10 years or more – you won’t be disappointed with this furnace. You won’t find a better-designed furnace – but be prepared to spend more.

Furnace Financing

We can help with financing options to get your new furnace replaced immediately.
We work with who try and take the hassle out of borrowing and make it simple to qualify.
They offer:

  • A quick and easy application process
  • 0% Financing available OAC

If you’re interested in financing or would just like to discuss what your options are for staying warm and comfortable contact us today.

Scroll to Top