Updated: May 18th, 2025
Most people have varying opinions about indoor heaters. They offer an easy, inexpensive and convenient way to beat the cold during the chilly winter season. These heaters use considerably less energy than HVAC units, too. They’re also user-friendly and don’t require expensive installation.
However, the risks associated with indoor heaters outweigh the benefits. It would be best if you only use them as a temporary solution when your heating system breaks down. Here are several drawbacks associated with various indoor heating units.
1. They May Omit Toxic Gases
There are multiple types of space heaters on the market today. Fuel-burning models run on oil, gas, petroleum or charcoal, which results in the production of carbon monoxide. Some of these heaters are vented and come with a chimney that helps to expel fumes; if this vent can be directed outside, you can keep the indoor air clean and fresh. Otherwise, it is still expelling combustion products into the room.
The pollutants from combustion can be dangerous in an indoor space. When you breathe in carbon monoxide, it takes up oxygen space in your blood. With insufficient oxygen supply in your body, you can lose consciousness or even suffocate. Space heaters that expel carbon monoxide are not rated for indoor use and will come with large warning labels.
More prolonged exposure to these fumes can damage your brain and heart. It can increase asthma risks or other respiratory conditions. What makes carbon monoxide very dangerous is that you can neither see nor smell it. By the time you start experiencing the effects, it could be too late.
2. They Can Lead to Fire Hazards
Indoor heaters can also cause a fire. Indoor heaters are the most common cause of fire-related deaths during winter. This is one of the main reasons that they are not recommended for prolonged indoor use and require special precautions when used temporarily.
Space heaters quickly rise in temperature. Flammable items, even dust, that is too close to a space heater can catch fire when exposed to the level of dry, intense heat that they produce. Curtains, bedclothes, stacks of paper or flammable furniture may catch on fire if they are in the path of an electric space heater.
Space heaters are also meant to be portable. While they’re easy to carry, this also makes them easy to tip. Homes with pets may find that the heaters get knocked down, which again can bring them into close contact with carpeting and other flammable materials.
3. They Result in Dry Air
Space heaters often cause very dry air; this can irritate your sinuses, dry your lips and skin and cause other irritating conditions like nosebleeds and rashes. They can also dry your eyes, making it harder to see clearly after a long day.
4.Others Are Quite Noisy
Some indoor heaters make annoying noises that can result in disturbed sleep. This is especially true with fan-based models that can create high-pitched whining sounds. Since fan-based heaters tend to run intermittently, light sleepers can be awakened multiple times a night to the sound of the fan cycling on and off.
5. They Can Cause Electric Shock
Like any electric item, a heater with improperly connected wires will cause sparking and shocks. The reason this is important to note here is that the current that an electric heater draws is very high. If a shock from a heater does occur, it is more likely to cause electrical burns or other health issues because of the amount of electricity that it requires to run.
6.They May Result in Burns
In addition to electrical burns, the temperature with which a space heater runs is typically very high. If they are not placed in a location that is inaccessible, they become a health risk for younger children or pets. This can be especially tricky when you consider that they must also be placed in an area that is secure, away from flammable items, near a vent if they’re not electric and in a portion of the room that will distribute the heat well.
Additionally, staring at the lit coils in a space heater has been shown to cause a burn to the corneas of your eyes.
7. They Have Extra Expenses
Most households operate on a fixed budget. The utility cost to heat the room to a comfortable temperature with a space heater is several times more than using a built-in system to heat your home. This is because they are less efficient and can only effectively heat one room at a time.
The high energy use of electric space heaters will also put a large demand on your electric circuits. It is best to plug it into an outlet with a GFI circuit breaker so that your system can shut down the outlet if it overloads it. If you use the heater on a high-demand circuit, you may have to be careful about what other electrical components you also run on that electrical circuit. Placing the heater on a high-demand circuit could mean dealing with tripped breakers.
8. You Can Only Use Them in Small Spaces
The indoor heaters offer a limited range of heat. Their primary purpose is to warm up small spaces, and it can be challenging to heat an entire house. If you have a bigger home, you may have to place several space heaters throughout the house. This makes it difficult to monitor them for safety and very expensive to run.
What to Know When Using a Space Heater
Always remember that a space heater should never replace your heating ventilation or air conditioning system. It should only act as a substitute source of heat to warm up small rooms for a limited time when no other option is available.
If you must use a space heater temporarily, check that the type that you are using is considered safe for indoor purposes. There will be something on the label that will say this; if you can’t find that information, choose a different heater that does say this. Choose a GFI circuit to plug into and limit using other high-current items like hairdryers and kitchen appliances that are plugged into the same electrical circuit. Be sure to dust, vacuum and declutter a large area around the heater and place it on a stable, non-burnable surface like stone or tile, not on wood or carpet. Keep it near the floor, not up high on a piece of flammable furniture. If you have kids or pets, consider putting a barricade of 3-6 feet around it. Follow any additional instructions from the manufacturer to ensure temporary safety. Then, call someone for a better heating solution ASAP.
Environmental Impact & Emissions
Fuel-burning heaters can emit nitrogen oxides (NOₓ) and volatile organic compounds (VOCs), contributing to indoor air pollution and irritating your respiratory system. Continuous use of propane or kerosene units also increases your home’s carbon footprint compared to electric heating sourced from renewables.
Economic Comparison: Space Heater vs. Central Heating
- Using a single electric space heater in a small room can cost 50–70% less per hour than running your central furnace for that same area.
- High-efficiency, programmable space heaters can reduce energy use another 15–20% versus basic models.
- However, heating multiple rooms with separate units often ends up more expensive than central heating—especially in poorly insulated homes.
Humidity Control & Skin Health
Most space heaters dry out the air, dropping indoor humidity below 20%. This can lead to dry skin, chapped lips, nosebleeds, and worsened eczema or asthma symptoms. To maintain comfort, aim for 30–50% indoor humidity by running a humidifier alongside your heater.
Indoor Air Quality & Allergen Management
- Fan-forced heaters blow dust, pollen, and pet dander around the room, which can aggravate allergies.
- Infrared and radiant-panel heaters heat objects rather than air, reducing airborne allergen circulation.
Enhanced Safety Best Practices
- Keep at least 3 feet of clearance around any heater—no furniture, curtains, or papers nearby.
- Always plug space heaters directly into a dedicated wall outlet; never use extension cords or power strips.
- Inspect cords and plugs before each season; discard any unit with frayed wires or scorch marks.
Cost-Saving Tips & Incentives
ENERGY STAR®–rated infrared or oil-filled heaters use 10–15% less electricity than non-certified models. Check with your electric utility for winter “demand response” programs—many offer \$50–\$150 rebates for reducing usage during peak hours.
Choosing the Right Heater for Your Needs
- For small, well-insulated rooms: choose a programmable ceramic or infrared heater for focused warmth.
- For larger spaces: oil-filled radiators provide even, long-lasting heat without drying the air as much.
- For occasional use: panel heaters with sealed elements minimize fire risk and don’t circulate dust.
When to Seek Professional Help
If you notice yellow-tipped flames (indicating incomplete combustion), persistent dry-air symptoms despite a humidifier, or unexplained spikes in your electric bill, contact a qualified HVAC technician. These could be signs of malfunctioning units or poor system calibration that require expert service.
Whenever you need help with indoor heating systems, you can always reach out to White Mechanical, Inc. in Foothill Ranch, CA. We are ready to help you with any cooling or heating tasks in both residential and commercial buildings. We have a great team of technicians conversant with the industry’s most current trends to resolve any issues within the shortest time possible.
We provide extensive services, including duct cleaning and upgrade, dryer vent cleaning, heating, cooling repairs, installation and maintenance. We are also highly experienced in ductless mini-split systems, ceiling insulation installations, ventilation and filtration services.
Call us today to schedule an appointment, and we will help create quality indoor air across all seasons.
