When it comes to saving money on energy, the most common reaction is to use less energy. In terms of home heating in colder weather, this means lowering the thermostat. But are there downsides to lowering thermostats temperature in the colder winter months?

It turns out there could be. While it might appear true that your house will use less energy throughout the day, you could also be introducing some additional risks around this practice.

Why Most Experts (Including Me) Recommend Lowering the Thermostats

If you are not home, or you are asleep, lowering the thermostat in colder weather is a good plan because your furnace has to work less. And since the furnace works less, it uses less energy. And the less energy you use, the less money you pay on your energy bills. With a programmable or setback thermostat (or newer smart thermostats), this is relatively straight forward. You can set a schedule and set your temperatures according to when you will be away, when you will be asleep and when you plan to get back home.

But there is no one size fits all solution. And sometimes even the best advice for all in general isn’t the best advice for you or your situation. So, let’s look at sometimes when perhaps turning the thermostat down in the Winter or in colder weather might not be the wisest course of action.

Reduced Comfort Due to Lower Temperatures

If you are sensitive to colder temperatures, or are prone to getting sick, setting the temperature colder probably isn’t worth it. Yes, you might save money on your heating bills. But are the savings going to extra medicine? Personally, I find that I sleep better in cooler weather so turning the temperature down at night is advantageous for my sleep cycle. But this isn’t true of everyone. If you find yourself cold at night, and can’t sleep well you are being negatively impacted by something you can control – the heat. And there shouldn’t be that steep of a price to pay for your comfort in your own home.

Or perhaps you just don’t feel comfortable bundling up in layers in your own home. I get it – you work hard for your home and you deserve comfort. It’s a matter of prioritizing comfort along with potential savings.

Health Risks Due to Temperatures Being Too Low

One of the downsides to lowering thermostats goes beyond comfort and directly to health. Yes you could get sick. But people who care for, or perhaps may be considered vulnerable such as elderly, chronically ill, infants, or people with certain medical conditions shouldn’t lower their thermostats too low. Doing so might put them at risk of getting seriously ill.

Cold and dry environments can exacerbate respiratory issues and increase the risk of hypothermia. While its relatively rare to contract hypothermia at home, the combination of lower temperatures and going outside in even colder temperatures can certainly trigger it.

Aside from that, there is a higher risk of stroke and falls in colder homes. Moreover, there is a greater risk of falls and other injury, as your body dexterity tends to decrease in colder weather. There is also a mental health impact, as living in a cold home can contribute to feelings of isolation, depression, and anxiety. There is also a feeling of financial stress related to energy costs can also affect mental well-being that is causing you to lower the temperature too low to begin with.

Again, there should be a balance between saving money and your health, and the safety of your home’s guests and inhabitants. Thus this remains one of the bigger downsides to lowering thermostats in colder weather.

Increased Condensation & Mold

Lower indoor temperatures can lead to increased condensation on windows and walls, potentially promoting mold growth and indoor air quality issues. When the warm moist air from the furnace turning on meets the colder window or wall surfaces, condensation forms. The condensation is a perfect breeding ground for mold, as the temperature of the air will remain relatively warm.

It isn’t practical to keep wiping the walls and windows, clearing them of condensation. A way around this would be to employ a dehumidifier to control the humidity in the air, but you would have to deploy these throughout the house, or else employ a whole house dehumidifier which is probably more cost prohibitive.

Increased Energy Use When Heating Up

This one depends greatly on the age and efficiency of your heating unit. If you have an older unit that is inefficient, it will have to work longer and use more fuel and energy to circulate the warmer air and get the temperature back up to the specified temperature. So the savings you might have realized by turning down the thermostat for 8 hours would be gone within 2.

Newer multistage furnace models don’t suffer from this same issue as they may be able to dynamically adjust their heating and dispersion intensity based on the demand and temperature of the rooms, in addition to many other factors. One such model is the Lennox SLP99v furnace, which is a variable high efficiency furnace that adjusts its capabilities to demand. The downside is this furnace is relatively expensive at over $7500 at many retailers and HVAC installation shops – though rebates and incentives to exist to bring the price down. Newer furnaces pretty much negate this argument as one of the downsides to lowering thermostats.

Pets Can Be Sensitive to Lower Temperatures

Let’s not forget about our cherished pets when it comes to downsides to lowering thermostats. While some animals such as Siberian Huskies love the cooler indoor temperatures, there are many that do not. In addition to cats and dogs, certain bird species and especially reptiles are very sensitive to cold temperatures. Prolonged exposure can not only make them uncomfortable but sick as well. This could lead to their discomfort, pain, possible veterinary bills and in some cases even death. As a responsibly pet owner, you should balance the lives of those you are responsible for with the need to save money on energy bills.

Battling the Downsides to Lowering Thermostats – Balance is Key

There will always be trade offs when it comes to deciding how cold is too cold, versus how much money can be saved. Unfortunately, its not something that you can directly measure, as the temperature outside can sometimes dictate how often the furnace turns on and how hard it works.

Here’s a simple trick though. On a day that you are home, you can simply find out how long your furnace was on for. You will have to assume a consistent flow of energy (even though that isn’t always the case, as newer models are variable speeds).

Set up one day where the temperature is tolerable in the house on a schedule (say, when you have the day off but you set the temperature lower). Repeat on another day, but this time keep the temperature at a consistent rate. If you notice barely any difference in the length of time the furnace runs, you can experiment with the temperature further to find a sweet spot that will lead to more savings while still remaining comfortable.

Find the energy usage/consumption of the furnace and then calculate what the furnace cost to run for those days and get the difference. That is your net savings. Then decide if you are comfortable with saving that versus the comfort you sacrificed.