- Why it matters: the TOG connection
- Sensor types and accuracy
- Cameras generate heat
- Location matters
- Practical tips - Our favourite suggestions
We all want to ensure our little ones are sleeping in a room that’s not too hot and not too cold, and that they are dressed right, but anyone with a little experience (or a quick google/reddit search) will tell you that your baby monitor might not be the device to rely on in your room when it comes to temperature.
That tiny temperature reading on your monitor can be a source of comfort or anxiety. But before you rush in to add or remove layers based on that number, let’s talk about why your monitor might not be telling the whole truth.
Why Accurate Temperature Readings Matter: The TOG Connection
TL;DR You might be significantly under-dressing your little one, leading to restlessness and early wake ups.
This is where the rubber meets the road. Knowing the actual temperature of your baby’s room is critical for safe sleep, and a big part of that is choosing the right sleepwear. Many parents use sleep sacks or swaddles with a TOG (Thermal Overall Grade) rating. Find out more about what TOG means here and how to read a TOG chart - basically higher TOG means warmer and lower means cooler.
Given what we're about to find out about reading the room and thermometer placement, our temperature reading might be as far as 4-5 degrees celsius away from the actual temperature, which might mean a substantially different TOG sleepwear suggestion.
A Quick Look at the Technology: How Accurate Is the Sensor?
TL;DR Dedicated room thermometers are typically higher accuracy than the technology used in baby monitors.
Many baby monitors, along with a wide range of other electronic devices, use a type of sensor called an NTC thermistor to measure temperature. NTC stands for "Negative Temperature Coefficient," meaning the electrical resistance of the sensor decreases as the temperature rises.
While NTC thermistors are great because they are small and inexpensive, they have some limitations. Their accuracy can vary, and they are typically only precise within a specific temperature range, often around 0.5 to 2.0 degrees Celsius.
In contrast, dedicated digital room thermometers can offer much higher accuracy, often within 0.1-0.25 degrees Celsius. This is because these devices use a more stable sensor (like an RTD, or resistance temperature detector) and are specifically designed and calibrated for temperature measurement, not as a secondary function of a video camera.
So, while the NTC thermistor in your monitor is perfectly capable of giving you a general idea of the room's temperature, it's not always a precision instrument.
The Not-So-Secret Heat Source: The Monitor Itself
TL;DR The monitor/camera itself generates heat, which can artificially throw out the measurement.
Think about it: your baby monitor is an electronic device. And what do electronics do? They generate heat! Even though it's a small amount, it's usually enough to feel by touch, and if the temperature sensor in your monitor is located close to the internal workings it’s going to pick up some of that warmth. Some specialty devices are calibrated to handle this, but this is not typical for your average baby monitor camera.
This can lead to your monitor consistently displaying a temperature that's a degree or two higher than the actual ambient temperature in the room. I’ve definitely noticed this with a couple of monitors I’ve used (and so have many others) – they always seemed a touch warmer than I expected.
Location, Location, Location: How Placement Affects Readings
TL;DR Above the bed closer to the ceiling can be 1-3 degrees warmer than mattress level
Beyond the monitor's own heat, where you physically place it in the room can have a surprisingly big impact on the temperature it reports.
- Up High? Think Warmer: Remember that basic science lesson - hot air rises. If you've mounted your monitor high on a wall above baby's cot it's going to be measuring the warmer air that accumulates near the ceiling, not the temperature down where your baby is sleeping. We've measured a difference as much as 3 degrees!
- Beware the Vents and Windows: Placing your measurement device near a heating or air vent is a recipe for a misleading reading. It will likely fluctuate wildly depending on when the system is running, and it definitely won’t represent the overall room temperature. Similarly, a spot near a window can be affected by drafts in winter or direct sunlight in summer, giving you a false reading of the room temperature.
If you're after more detail on room ideal thermometer location in your nursery be sure to checkout our guide including thermometer placement.
So, What Can You Do? Practical Tips for Better Readings
Okay, so your thermometer might not be a perfectly calibrated scientific instrument. What can we do to get a more reliable idea of the nursery temperature?
- Follow the Manufacturer's Guidelines: Check your baby monitor's manual for specific instructions on placement. They often recommend a certain distance from the crib and away from heat sources.
- Position at Baby's Level (Indirectly): Aim to place the monitor on a stable surface, like a dresser or nightstand, at least about a metre (around 3 feet) away from the crib. This helps minimize the influence of the monitor's own heat and any localised air currents around the baby.
- Keep Away from Extremes: Avoid placing the monitor directly under vents, near windows, or high up on walls. Choose a more central location in the room.
- Try a Separate Room Thermometer: For the most accurate reading, especially if you're concerned about the temperature, try using a separate, dedicated room thermometer placed near your baby's crib. These are often designed specifically for measuring ambient room temperature. We recommend the Sleep Like Goldilocks Smart TOG Guide for this.
- Trust Your Instincts: Ultimately, the number on the monitor is just one piece of the puzzle. Pay attention to how your baby feels. Are they sweaty? Do they feel cold to the touch? Dress them appropriately for the conditions, erring on the side of caution and avoiding overheating you can find safe sleep guidelines here from Red Nose Australia.