Serving the entire Portland Oregon Metro Area
Midway Heating Company
Sep 14, 2017

What’s the difference between single stage, 2-stage & variable speed furnaces

Portland Furnace installationIf it’s time to replace the furnace in your Portland Oregon home, then you need to know the differences between a single stage, 2-stage and variable speed furnaces.

We want you to understand these different types of furnaces so you can find the perfect furnace that meets the comfort needs of your family while saving you money on your monthly heating bill.

Single stage furnace

A single stage furnace or 1-stage furnace means has only 1 setting (high) so whenever it’s operating, it’s running at full capacity-no matter how cold it is outside.

A single stage furnace is not as efficient as every time it turns on, it’s working at full blast to produce as much energy as possible.

2-stage furnace more efficient than 1 stage

So, you have probably already guessed that a 2-stage furnace has 2 levels of output-high and low.  Most of the time the furnace runs on the low setting and only kicks into high gear in really cold weather when an extra boost is needed to bring your home up to the desired temperature.

On average, a 2-stage furnace runs on high about 25% of the time.  A 2-stage furnace runs for longer periods of time because it’s running on the low setting BUT this type of operation provides a more even heat distribution so it reduces air fluctuations or cold spots in your house.

Most homeowners find they don’t need to adjust the thermostat as often as with a single stage furnace.  Plus, it’s much quieter as it’s not operating at 100% capacity all the time and is more energy efficient than a single stage furnace that operates on ‘high’ all the time.

Variable speed furnace is most efficient

With a variable speed furnace, the ‘variable speed’ doesn’t refer to the furnace itself but to the furnace’s indoor blower motor.  Variable simply means that the blower motor operates at different speeds to more accurately control the flow of heated air to your home.

Lennox 95% AFUE gas furnaceIts advanced technology is able to constantly monitor and adjust its blower settings to account for things in your home that restrict airflow, such as your ductwork, furnace location and even dirty filters.

Being able to constantly adjust the blower motor means your furnace runs much more efficiently than a single stage or 2-stage furnace so you save money and energy.

These types of furnaces are also great for zoning, which allows you to set the thermostat on different settings for various parts of your house.  Of course, there’s many other benefits to a variable speed furnace so keep reading.

Comfort and efficiency in 1 furnace

A variable speed furnace provides a more consistent comfort as it gets rid of temperature swings.  For example, the SLP98V from Lennox has Precise Comfort™ technology that adjusts the fan speed, heat and airflow in increments as small as 1% for the ultimate in temperature control.

The variable-capacity function is like cruise control for your furnace’s operation and these automatic adjustments is why this type of furnace delivers maximum fuel efficiency.

You won’t even hear it running

A variable speed furnace is definitely quieter than a 1 or 2 stage furnace.  It runs on a lower setting the majority of the time so the amount of heat that’s required is lower (as opposed to being on ‘full blast”) so there’s no big blast of air when it starts up. In addition, the SLP98V from Lennox (mentioned above) uses sound absorbing materials in its construction to further dampen any sound.

Better air quality

Portland Furnaces

Even when the furnace is not on, the motor in a variable speed furnace can be in constant operation so it will circulate the air in your home 24/7.

That means there’s more air going through the filter and therefore, more contaminants (bacteria, viruses, and mold spores) are being removed.

Compare this to a single or 2-stage furnace that only circulates air when its running and you can see a variable-speed furnace truly does deliver better air quality.

The other advantage to continuous airflow is that since warm air is constantly being redistributed throughout your home, your furnace will not have to operate as often. This results in less energy consumption and lower heating bills for you.

Free estimates on furnace installation

In summary, a variable speed furnace is the cream of the crop when it comes to energy efficient furnaces.  While they cost more than other furnaces, they will pay for themselves in the long run.

Now that you know the difference between single stage, 2-stage and variable speed furnaces, you can start doing your research and be sure to contact Midway Heating for your free estimate.