5 Heating Myths That Are Costing You Money – HVAC and Energy Pros Explain What Works Instead

Outdated heating myths not only spike your bills for no good reason, but they won't keep your house warm or make you more comfortable this winter.

From cranking the thermostat when the temperature dips outside to closing vents in unused rooms and lowering the settings during the day, our HVAC and energy pros reveal the enduring heating rules that no longer serve modern homes and will only work against you.

Don't waste money this winter using old rules, and instead keep your house warm with wallet-friendly and planet-friendly tips from the experts.

The Outdated Heating Myths to Swap for Modern Rules, for Modern Homes

After saying goodbye to the 66° Fahrenheit rule in my home for two months, and seeing pesky window condensation disappear and my family's comfort rise without our bills spiking to match, it got me thinking about the other heating 'rules' we've inherited, which don't serve our modern homes or needs.

This is especially relevant when intensely cold weather systems, such as the Arctic air outbreak, sweep across the US.

HVAC technician and founder of Air Conditioner Lab, Josh Mitchell, says, 'A lot of old heating advice still floats around because it made sense decades ago, when homes had poor insulation, single-pane windows, and inefficient furnaces.

'But newer homes are tighter, systems are smarter, and energy use doesn’t behave the same way. Here are a few heating habits that don’t hold up anymore, and what to do instead.'

1. Setting the Thermostat and Leaving It All Day

In bygone decades, boilers coped better with steady temperature settings rather than dynamic heating. Now, modern homes across the US are largely equipped with better heating systems, as well as advanced insulation, windows, and building materials that keep heat indoors.

Josh explains, 'This heating myth came from the idea that keeping a steady temperature avoids wasting energy. It made sense with older boilers that took forever to ramp up.

'But modern systems heat faster and cycle efficiently. Leaving it at 72°F all day means you’re heating empty rooms. Use a smart thermostat and set it to lower temps when you’re sleeping or out.'

'Dropping the temperature 7-10 degrees for eight hours saves around 10 percent on your bills a year.'

I tested this myself after having a smart thermostat installed, similar to the Nest, available at Amazon last winter, and the clever technology constantly checked my indoor temperature and switched the heating on and off to maintain steady temperatures 24/7. The result was a saving of 100s of dollars over the course of winter and constant comfort.

2. Turning the Thermostat Way Up to Heat Faster

I remember watching my mother crank up the heating whenever we had a particularly cold day in our 1920s home, but I also remember my father loathing the enormous bills that came with heating that drafty old house.

Josh says nowadays, turning the heating all the way up does nothing but stress the system and waste energy.

'This one’s pure psychology,' Josh explains. 'Furnaces and heat pumps don’t blow hotter air just because you set the thermostat to 80°F. They run at the same output until the target is reached. You’ll just overshoot and waste energy. Set it to the temp you actually want and let it run.'

Blocking drafts under doors with washable stoppers and filling gaps with crackproof and weatherproof silicone, both available from Amazon, around your windows to stop drafts will actually make you feel warmer by curbing chilly air sneaking in, and hot air leaking out.

I did this myself with a doubley-drafty entryway that led straight into my open-plan living room and immediately felt the benefits. It also stopped my smart thermostat from needlessly cycling on because of the cold air near the front door, which was causing cold spots and uneven heating upstairs.

3. Closing Vents In Unused Rooms Will Save Money

This outdated heating rule only puts pressure on heating systems and creates hot and cold spots.

Josh says, 'This myth came from thinking you could “redirect” airflow where it’s needed. But closing vents increases static pressure and throws off system balance. It can even cause short cycling or duct leaks.

'A better fix is zoned heating or installing dampers to control flow properly. At the very least, leave doors open and let air circulate freely.'

Closing vents only puts extra stress on your system, leading to unnecessary repairs.

Dean Mahmoud, CEO of EcoGen America, adds, 'Many homeowners assume closing the vents of unused rooms in a house will lower their heating bills by reducing the amount of heated space. This concept came from older houses with gravity-fed furnaces or window unit heaters that could be physically isolated to save fuel.

'But modern central forced air systems use a balanced loop system and require a certain amount of airflow to function properly. Closing all of your register vents increases the static pressure in the duct system and makes the blower work extremely hard to overcome this increased resistance.

'Excess pressure will most likely cause duct leaks to increase in size or rupture, causing the paid-for heat to be blown into attics and walls instead of the living space that was intended.'

Dean reveals that his team often sees early failures in customers' blower motors and increased energy bills due to this outdated practice, rather than the intended savings they hoped for.

'For your ventilation system to breathe as intended by the manufacturer,' Dean adds, 'you need to allow all of the vents to stay open.'

4. Using Fireplaces Without Adjusting Your Heat

I recall the thrill of lighting our fireplace in our childhood home, and it was the perfect way to make our large living room feel cozy. But I also recall the absolute chill I felt, stepping out to the rest of the home, as often, the thermostat was lowered to conserve energy when it was lit.

Misusing your heating when your fireplace is in use will not help in a modern home.

Josh explains, 'People assume running a fire saves money. But traditional fireplaces often suck warm air out of your house through the chimney, especially if the central heat is on. That pulls cold air in from outside to replace it.

Ethan Heine, who has worked in the energy industry for decades and leads Sun Trek Solar, a solar power company, adds, 'Turning off the central heater while you are enjoying the fire will probably reduce how much electricity your central heater uses, but, conversely, the drawback is that fireplaces pull the warm air inside your home and dump it outside via the chimney, so any rooms opposite the one with a lit fireplace will probably see very little to no warm-up effect from the fire.'

He advises thinking of your fireplace as a means to add some extra warmth and ambiance to your home, and let your central heating system do its job to maintain a consistent temperature in all areas of your home.

Ethan adds, 'Make sure to close the damper completely after each fire to prevent the loss of warm air through the chimney.'

There are ways to get more heat from your fireplace, but always clean it regularly, as well as your chimney, to avoid a buildup of flammable natural materials that can become a fire risk.

Adding a creosote cleaning log, available from Amazon, to one in every forty fires you light in your fireplace will help break down and remove the flammable buildup.

5. Ignoring Airflow and Filter Changes

Sometimes, it's the lack of heating upkeep that can hinder your family's comfort at home over winter and in extreme cold weather snaps. Ignoring vital winter home maintenance tasks, such as cleaning your HVAC system and its components, can lead to costly damage over time.

HVAC tech Josh explains, 'Some people treat airflow like a non-issue. But blocked returns, dirty filters, and blocked radiators all reduce efficiency. If your filter is dirty, your furnace runs longer and wastes energy.

'I always tell people to check filters monthly and replace them every one to three months. Make sure vents aren’t blocked by furniture or rugs either.'

Air vents can gather dust and be prone to mold, so make sure they're on your schedule to check and clean.

Allowing moisture channels – space around furniture and between it and the walls – will reduce the risk of mold in your house by improving ventilation and reducing the spots in which mold can settle and thrive.

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Meet the Experts

Josh Mitchell

Josh is an experienced HVAC technician and the founder of Air Conditioner Lab, bringing expert advice on heating, air purifiers, and dehumidifiers, as well as troubleshooting for homeowners.

Ethan Heine

Ethan has worked in the energy industry for decades, and currently leads a solar company that provides service to over 10,000 customers in the western US, so he is surrounded by real families that want to be able to affordably keep warm and pay their bills.

Dean Mahmoud

With 14 years of experience in the industry, Dean analyzes total home energy consumption to determine if solar conversions are economically feasible for the company's customers.

Outdated heating habits cost people comfort and money, with modern HVAC systems responding better to smart schedules, balanced airflow, good ventilation, and minor adjustments that match how you live day to day.

These tweaks don’t take much effort, but they stop a lot of waste and help you be more sustainable at home, whilst cutting your energy usage and costs.