Should I Turn Off My Gas Furnace in the Summer?

Oscar Garner

By Oscar Garner

Last Updated on June, 2024

Our gas furnaces work long and hard to keep us warm during the chilly season, so the summer is the perfect time to give them a well-deserved rest. 

Or is it? 

Knowing whether to turn off your gas furnace in the summer can get complicated. Depending on how your gas furnace works, several benefits and drawbacks exist. 

In this article, we’ll provide a comprehensive guide to help you better understand your HVAC system and make the right decision. Let’s begin! 

Quick Summary

  • The decision to turn off a gas furnace in the summer depends on factors such as the age of the furnace, its method of operation, and whether it shares components with the air conditioning system.
  • Older gas furnaces consume more energy when kept on, leading to higher utility bills. Turning off the furnace, including the pilot light, can result in significant energy and cost savings.
  • Turning off the gas furnace in the summer can also have drawbacks, such as potential moisture damage or the need for professional assistance to turn it back on. It is important to evaluate these factors and consult with experts before making a decision.

Should I Turn Off My Gas Furnace During the Summer Months?

A technician repairing a Gas Furnace

You should turn off your gas furnace during the summer if you have an older model. Older furnaces consume more energy when kept on, leading to higher utility bills. 

You can identify an older furnace by locating the pilot light- a small blue flame usually found on the front of your furnace or near the control knob. 

This light ignites gas supplied by your burner to generate heat. A continuously burning pilot light will produce moisture to heat your home. This is great for winter and the occasional cold nights in spring but can make your house akin to a microwave oven in the summer. 

As such, you should turn off the furnace once you feel that the weather is warm enough.

When turning off your gas furnace, remember also to turn off the pilot light. This prevents the furnace from accidentally turning on.

Keeping the pilot light off will also minimise your carbon footprint and reduce the risk of furnace issues or malfunctions. 

How to Turn Off My Furnace?

Turning off your gas furnace is a straightforward process. The first step is to change your thermostat settings. You can adjust it to a cooler temperature or turn it off altogether. 

The next steps are to switch off the pilot light and cut the gas supply to your HVAC system. 

How Do I Turn Off My Pilot Light?

You can turn off your furnace pilot light by locating the gas valve. This valve is usually found behind an access panel or at the bottom of your unit. It should have three labels: “On,” “Off,” and “Pilot.” Once you find it, turn the dial to the “Off” position to extinguish the pilot light. 

How Do I Turn Off My Gas Supply? 

Ensure you only cut off the gas supply to your furnace, not other appliances requiring natural gas, such as your stove or dryer. You want your house to be cool, not your dinner cold or your clothes wet. 

You can turn off the main gas supply with the shutoff valve on the pipe connected to your furnace. Turn the valve 90 degrees clockwise to stop the flow of natural gas to your furnace. 

Should I Turn Off the Central Heating System? 

You can turn off your central heating system if it has separate electrical components for your furnace and air conditioner. This means you can cut the electricity supply to your furnace without disrupting the cold air flow from your AC. 

Switching off the main power also lets you prevent your gas furnace from being turned on by mistake. 

What if I Don’t Have a Pilot Light?

You probably won’t find a pilot light if you own a modern furnace. Most newer models run on an electronic ignition that stops the gas flow to your heating system when the furnace is turned off. 

In this case, there’s no need to worry about unnecessary gas usage. 

Should Modern Furnaces Be Turned Off in the Summer?

A modern Furnace Installed in a house

Since modern furnaces use an electronic ignition instead of a pilot light, they can function without using natural gas. This means you don’t need to shut off your gas furnace during summer, especially if the furnace and air conditioning use shared components. 

However, leaving the gas furnace on throughout the summer can cause issues. Ensure you replace the air filter and schedule regular furnace maintenance to keep the appliance in optimal condition. 

What if My Furnace Controls the AC?

So, what do you do if your air conditioner won’t work without the gas furnace? 

Even more than chilled beverages, a working AC is key to surviving those hot summer months. If you have a forced air furnace, keep it on to ensure your central air conditioning system works. 

In this unit, the furnace controls the fan function of your AC, ensuring that cool air is pushed through the vents and into your house. 

Leaving the gas furnace on throughout the summer will consume energy and cost you on utilities, but staying cool in the heat might be worth it.

Advantages of Turning Off Your Gas Furnace in the Summer

Unless your air conditioning depends on your house heating system, you should consider giving your furnace a break during the summer. 

The primary benefit of doing this is that you’ll have reduced electricity bills all summer. Continuously running gas furnaces consumes a lot of energy, and you’ll be surprised at how much money you can save by keeping yours off for extended periods. 

Even if you turn the furnace on occasionally for hot water, you will still save energy and see a notable change in your overall utility costs. 

If you have an older furnace, you can also save on gas by extinguishing the pilot light. 

Moreover, switching off the gas furnace lets you reduce the emission of carbon monoxide, which contributes to a smaller carbon footprint and helps the environment. 

Giving your gas furnace a break will also keep it in optimal condition and reduce future repair costs. 

Disadvantages of Turning Off Your Gas Furnace in the Summer

As we discussed earlier, switching off a forced air furnace will stop the air conditioning in your house. However, there are other drawbacks, too. 

One major issue you might face is moisture damage. When your unit is turned on, the heat from the furnace pilot light evaporates the moisture inside your system. However, when the pilot light is shut off, the moisture can build up and corrode the metal inside your furnace.

This can cause leaks or malfunctions and you’ll need the help of a repair service to fix your heating system. 

You can prevent this problem by periodically turning on your pilot light so that the flame can evaporate the moisture. 

While turning off your gas furnace is straightforward, turning it back on can be a little trickier–especially if you haven’t done it before. 

Tips to Remember When Turning the Furnace on Again

A man is turning on the Gas Furnace

Restarting your gas furnace by yourself is tricky, but not impossible. Here are some tips to help you out:

  • Before attempting to switch on the furnace, check the instructions on the front access panel or the user manual. 
  • Replace the air filter. 
  • Do a safety check around your furnace to ensure no gas or water leaks. 
  • After confirming that there are no leaks, turn on the gas supply to the furnace. 
  • Turn on the pilot light and check whether it is working properly. A bright blue flame usually indicates a working pilot light. 
  • Gradually increase the temperature on your thermostat. 

If you are unsure about any of the above steps, spot any hazards, or notice that the pilot light is discoloured, don’t hesitate to call a professional HVAC technician. 

You should also schedule a furnace maintenance service to ensure your appliance works properly.

Conclusion

Turning off your furnace at the start of summer might seem like a no-brainer. After all, Mother Nature is there to keep you warm, you get to cut down on utility costs for the next few months, and you’re helping the planet. 

However, some circumstances require that you keep your gas furnace on even when it’s warm out–whether to avoid technical problems with your appliance or keep the air conditioner working. 

If you still have doubts, we recommend consulting your manufacturer or an HVAC professional to guide you on how to proceed. 

FAQs

No, it is not safe to turn off your gas furnace in the spring because doing so could cause moisture damage to the appliance. It is advisable to wait until summer to shut off your gas furnace.

Yes, older furnaces should be turned off during the summer. Older models often use pilot lights, which consume more gas compared to newer furnaces. Turning them off can help save energy.

The pilot light on a furnace is typically located in the front access panel or near the control knob.

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