Thermometers around the country are dropping lower and lower. Fall has arrived, and with it, blustery winds, pumpkin spice lattes and, inevitably, brisk temperatures. For many, this means digging scarves, hats, maybe even light mittens out from the back of the closet for the first time since last year, and perhaps more to the point, a space heater or two.

Every year, families go through the same song and dance in their heads, replaying a riddle that never seems to land on a solution: Which is more cost-effective? Running the furnace or plugging in space heaters? But if you’re tired of all the guesswork and want a definitive answer, then it’s time for us to examine which of these two home heating technologies can keep you toasty without burning through your budget.

“The best way to save energy is to avoid consuming it – but that’s not a solution in colder seasons.”

Before we get started

Time and time again, energy experts will state definitively that the best way to save energy is to avoid consuming it. No matter where in the U.S. you live, energy costs money, and on average, those costs trend upward in the wintertime.

Why? A number of reasons. It could be because of increased demand, since snowy weather tends to keep people inside spending energy. Maybe it’s the shorter days. After all, when night falls early, people spend extra electricity lighting their homes. Perhaps the problem is greater than the home, an issue of market shortage. According to the Conservation Law Foundation, in the Northeast especially, natural gas supplies into the area from out of state haven’t quite caught up with regional wintertime demand, which impacts pricing. Whatever the case may be, every measure a person takes to avoid turning on the thermostat or space heater at all will forcibly save them money.

But that’s not a solution in colder seasons. Frigid temperatures can cause structural damage to the home, not to mention health problems for those inside. So while a heavy blanket or a wooly sweater might help avoid these heating costs now, in a couple months, they simply won’t be enough.

The short answer to the question of space heaters versus HVAC systems won’t be satisfying for inquiring minds, but it is true: Both can warm without waste, so long as the owners practice safe and intelligent use.

Don't be hypnotized by its warm glow. A space heater could be costing you big bucks.

Don’t be hypnotized by its warm glow. A space heater could be costing you big bucks.

The run down on heating up

To determine HVAC efficiency, homeowners will have to examine their energy rates, their typical autumnal consumption and the size of their homes to gauge a rough estimate. This can be done in a number of ways depending on what works best. If a home is heated with oil, for example, tracking consumption can be as easy as it would be for a car’s gas tank. Take the full tank’s cost – which may fluctuate between refills, but only slightly – and divide it by the number of days until it needs to be refilled again. So if an 300 gallon oil tank costs $800 to fill and 30 days until it needs refueling, the family upstairs spends more than $25 a day to heat their home. In this case, supplementing with space heaters can spread the HVAC’s resources over a longer period of time.

However, as the U.S. Department of Energy explained, space heaters are, by their very nature, not terribly efficient themselves, especially old ones. To put things in perspective, if the average space heater consumes 1,500 watts of electricity, that’s the equivalent of more than 135 laptop computers running simultaneously at 11 watts a piece, according to a study by the Lawrence Berkeley National Laboratory.

But they do have one advantage over HVAC systems: They can heat a single room at a time. When the the chill sets in this fall and you question whether space heaters would be more energy-efficient and cost-effective than cranking up the thermostat, asses your own situation first. Are you the only one home? If not, is everyone in the house in the same room as you? Is it cold, but not so cold the pipes could theoretically freeze? In these scenarios, using newer space heater models could actually save you money and energy this winter. Just bear in mind: Never underestimate the power of an HVAC system to provide affordable, effective energy use just because of its size.