Auto Versus On: Which Setting Is Best for Your Furnace This Winter?

Home Furnace

Warm and cozy or cheap (or at least affordable) – that is the dilemma so many of our furnace customers struggle with when another Canadian winter rolls in.

After all, while it feels great to walk into your warm, comfy space, it doesn’t feel so great to pay the heating bill each month.

Is there a way you can stay comfortable all winter without running up a hefty bill?

One of the keys to managing winter energy expenses is figuring out how to optimize your furnace run times. There are several tools to help you control how much you pay to keep your family warm and that is exactly what we will look at in this post.

Basic Furnace Thermostat Types

Before we get too far into this topic, it might help to start with a basic overview of the “typical” furnace thermostat board.

Like the thermometer the doctor uses to take your temperature, the furnace control board tells you about your furnace output and current settings.

Depending on the age, make and model of your furnace, you may see one of four types of thermostats:

Mercury dial

This bi-metallic (two metal pieces) is round and rotates manually. You will see the brand name in the center and two temperature strips – upper and lower for cool and heat. It uses actual mercury to sense and control temperature.

Mechanical contact box

This boxier analog thermostat also displays two temperature strips – one at the top and the other at the bottom. It uses a simple mechanical contact point to sense and control temperature.

Digital thermostat

The digital thermostat is what more of us are used to. Gone are the two temperature strips and in its place is a simple numeric readout that tells you the temperature depending on which mode you select (cool, heat).

Programmable thermostat

The programmable thermostat is the brains behind the body of the furnace itself. As its name suggests, you can use this thermostat in very precise ways to control your energy expenses all year. Happily, many programmable thermostats sold after-market can integrate with your existing furnace if you want to upgrade.

Basic Furnace Thermostat Controls

Depending on the type of thermostat your furnace is equipped with, you may find these basic settings located in different places.

Heat versus cool

This simply tells you whether you are running your furnace or your air conditioner.

When the setting reads “off,” you are not using either.


If you have an air exchanger installed, when you have the fan setting activated, your HVAC system is pulling air in from outside, filtering it through the furnace filter and using it to ventilate your home. Otherwise, the fan is circulating and filtering the air inside your house.

This air is not being heated or cooled first.

On versus auto

The on setting tells your furnace to run continuously regardless of what the thermostat setting may be.

The auto setting tells your furnace when to run and when to stop running based on where you set the thermostat.

Auto Furnace Setting Versus Programmable Thermostat

You might be wondering what the difference is between using the auto setting on your furnace control board and using a programmable thermostat.

Using the auto setting is a very basic type of manual programming tool. You can set the thermostat and switch the furnace to the auto setting and this tells your furnace to stop running when it reaches the temperature you set.

But that is all the auto setting can do.

For example, if you leave the house, your furnace will continually start up again every time the temperature inside your home drops below the setting you have selected.

If you use a true programmable thermostat, however, you can give your furnace further instructions for the times you don’t need it to run at all. You can also tell it the times to lower the thermostat a few degrees, such as during the night when everyone is tucked into their warm covers and asleep.

This can be a real money saver!

According to Energy Star, you could conceivably save up to 35 percent on annual energy costs (heating and cooling) by using the full functionality of a true programmable thermostat.

If the programmable thermostat you choose is an Energy Star model, you automatically stand to trim a further $50 off your annual energy bills.

What Does 35 Percent Savings on Heating Expenses Look Like?

Even a 35 percent energy savings isn’t too exciting unless you can translate that into solid dollars and cents.

According to FAO-Canada, the typical Canadian household spends about $2,358 per year on overall energy expenses, including but not limited to heating and cooling.

Natural Resources Canada further tells us that the average Canadian household spends 61 percent of total energy expenses on heating and 3 percent on cooling – so 64 percent total.

What would it look like if you could trim that 64 percent, or just over $1,500 annually, by installing a programmable thermostat?

It would look like saving $525.

Considering that the typical after-market programmable thermostat starts at around $100, this upgrade will pay for itself before a quarter of the calendar year has elapsed.

Truly “smart” programmable thermostat systems – the kind that expand to controlling additional aspects of your home such as lighting and home security – will cost more. But they also do more.

Happily, you really don’t need to upgrade to a “smart” thermostat to reap the cost-savings benefits of using a programmable thermostat. You just need the option to program your thermostat by the hour and the day to avoid paying for heat you won’t use.

Get in Touch

Are you ready to start trimming your winter furnace heating bills? We can help!

Contact us online or give us a call at 905-549-4616.

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