If smart lights, thermostats and security cameras are the staples of the smart home, think of sensors as the invisible network meshing everything together. Or, if you prefer, the eyes of the smart home.
But the word sensor is itself pretty vague. There are many sensors out there designed to fulfill different purposes: movement sensors, light sensors, temperature sensors, and plenty more.
The best part about using sensors is that theyâre (mostly) super easy to install, often with no wiring required, which will be music to the ears of renters. But before we dive into the specifics of each type of sensor and the best out there, letâs go over some need-to-know pointers.
Smart sensors: Things to know first
I think it was the Insane Clown Posse who said, "Goddamn smart home motion sensors, how do they work?" Many of the sensors you pick up today are wireless, allowing you to place them wherever you like, but the position of these sensors is key; if you have professional installing your smart home they should be able to provide some pointers â or just do it for you.
If youâre going DIY, think about the locations that are going to be most effective but least likely to cause false alarms. Say youâre using a motion sensor, youâll want to put it in a place an intruder is most likely to pass by, but not somewhere it might be triggered by daily visits from the next-door cat.
Read this: How to build a smart home when you rent
Naturally, you also need to think about compatibility. Are the sensors Z-Wave or Zigbee? Do you want to buy the sensors as part of a bundle, which companies like Ring and Samsung offer, or are you better off buying the sensors individually?
Some smart home appliances also double as sensors of sorts. Some smart doorbells see whoâs at the door and send you an alert to tell you if itâs someone they recognize. Below, we've broken things down into the major categories of smart home sensors, and included some of our top picks.
No points for guessing what these do. Motion sensors are meant to detect movement in a select area of your home, and come in a range of options. A popular type of motion sensor is one you can attach to a door or window, which will alert you should it detect either of them being opened.
One thing to be aware of: You want to put motion sensors in a place someone is likely to pass by, not simply walk in front of. This will make it more accurate at detecting movement. There's no end of options out there, most of which use the Z-Wave protocol.
Some motion sensors, like the Everspring Compact Z-Wave Motion Sensor, have an adjustable sensitivity. In researching motion sensors, you might come across something called PIR. This stands for passive infrared sensor, which detect warm bodies as they pass by. Other types of motion sensors include MW (Microwave), which bounces microwave pulses off objects; ultrasonic waves; vibration, which is a little less accurate and more prone to false positives; and sometimes a combination of more than one type.
Having an adjustable range can be hugely beneficial, depending on the space you're using it in. The key thing is to check the motion coverage and sensitivity before you buy.
Some also come with a feature called 'Pet immunity', which is exactly what it sounds like. They won't alert you if they detect movement from smaller beings in your home, and there's usually a maximum size noted (the Ecolink Z-Wave Plus Motion Detector is immune to movement from pets as large as 55 lbs, for example).
A final note: Some motion sensors are meant for specific tasks, like the Philips Hue motion sensor which is solely designed to trigger lights when it detects movement.
Samsung SmartThings Motion Sensor
Samsung sells something called a Multipurpose Sensor specifically for doors and windows, but if it's a general motion detect you want, go for the Motion Sensor. It's ever-so-slightly more expensive, but it's less limited, and adds a temperature sensor too. You will need a SmartThings hub to use it.
Hue Motion Sensor
If your concern is less about security and more about using motion to turn on the lights in your home - which, let's be honest, still feels amazing in 2019 - then Philips sells a motion sensor for its Hue lights. It can even detect optimum daylight levels to conserve energy as needed.
Fibaro Motion Sensor
Fibaro makes one of the best sensors for HomeKit users. There's a Z-Wave version too, so make sure you choose the right one. It's a little more expensive, but it's also better looking than most other motion sensors out there, if a little Eye-of-Sauron.
Moisture/water leak sensors
Handy, these, if you want to avoid coming home to a drenched house (or at least want a heads up). A lot of the traditional ones use alarms to alert you that somethingâs sprung a leak, but what if youâre not home to hear it blaring?
Moisture detectors can be placed in many places. Currently we have one on a washing machine that's outlived expectations (and which we're expecting to fall apart soon), but heaters and sinks are other obvious risk areas.
A key consideration is whether you want audible alerts as well as smartphone notifications. Not all of these sensors do both. Also, what type of notifications do you want? A text? A call? Think about that. And also consider what you already have in your home. Some of these sensors require a hub, but some can connect directly to Wi-Fi. If you want to connect your water sensors with other smart home devices â say, to switch off your lights if a leak is detected â then some will let you do so. And in some cases you can use IFTTT to build on the available options.
One of our top picks here is the iHome Wi-Fi Dual Leak Sensor (seen above), for which you can also set up triggers with iHome smart plugs to switch them off when a leak is detected. Samsung's SmartThings Water Leak Sensor works with the SmartThings hub and, in our testing, has proven to be pretty sensitive, even if it doesn't have quite as large a detection field.
Some water sensors also double as freeze detectors. The Roost Smart Water Leak and Freeze Detector, for example, or the less smart (but very capable) Honeywell Lyric Wi-Fi Water Leak and Freeze Detector.
iHome Wi-Fi Dual Leak Sensor
The iHome leak sensor has dual probes for added coverage, and a battery life of two years. It's also loud as hell, with the option to push alerts to your smartphone - or integrate it with other iHome devices, if you have them.
Samsung SmartThings Water Leak Sensor
Samsung's leak sensor doesn't have as much coverage as the iHome, but it's still easily one of the best options out there. It also monitors temperature, while SmartThings integration means you can tie it up with Alexa or Google Assistant.
Weather sensors are a great way of seeing what's going on outside - without actually going outside. But this isn't just the lazy person's rain detector. Weather sensors scoop out tonnes of useful and interesting data about outdoor conditions, including temperature, humidity, wind, local rainfall, air pressure and more. Remember when we described sensors as the eyes of the home? This is like sticking a pair of eyes on the outside of your house.
Read this: The best air quality purifiers and monitors
For extra smart points, you can even get some of them talking to other smart devices in your home, like lights, to make adjustments based on the forecast. Netatmo's Weather Station is worth a look if you're after something discreet. There are two parts â an indoor and an outdoor tower â that give you information on air quality, temperature and humidity. The outdoor one also offers barometric pressure and a weather forecast, while the indoor tower monitors CO2 and even sound. You can even add on some additional sensors including a smart rain gauge and anemometer (which measures wind).
Netatmo Weather Station
Netatmo does things differently with a weather station that actually looks... quite good. Trust us, that's a rarity. The indoor module monitors CO2, temperature, humidity and air quality, while the outdoor tower tracks barometric pressure, outdoor air quality and weather conditions, and like the indoor one, temperature and humidity. There's Alexa and IFTTT support - but not HomeKit.
Ambient Weather WS-2902A
Wind speed, wind direction, UV, rainfall, solar radiation, barometric pressure, indoor/outdoor temperature, indoor humidity, dew point, heat index, wind chill. Did we miss anything? Oh yeah, Alexa integration too.
Temperature and humidity sensors
Temperature sensors are at their best when working in conjunction with smart thermostats. Sure, they can be helpful when they're alerting you that it's too hot or humid, but they're most effective in making your smart thermostat more efficient.
The best example here is the Ecobee4's Room Sensors. Temperature sensors are great for effectively cooling or heating rooms. Let's say your thermostat is in your hallway and its 71 degrees Fahrenheit. In your room, it's 67 degrees Fahrenheit. Having a Room Sensor in that room will tell your HVAC that your room is colder than the hallway, and that it might need a little more heat.
Similarly, Ecobee's Room Sensors also check occupancy. So if they sense that someone is in a room, it'll heat it up, but if it's not then it won't waste the energy. This can make your heating system feel like it's following you around the house, which is super futuristic.
Temperature sensors can also be used to trigger other appliances. For instance, if it gets too warm maybe you can activate your fan. Or if it gets too cold you can activate your coffee machine. It's simple things like that that can end up making a world of a difference.
Ecobee Room Sensor
You'll need an ecobee4 and ecobee3 lite thermostat to use these, but the result is a much more intelligent way to heat your home. The sensors measure the temperature of individual rooms as well as where people are - so it can heat the home more efficiently.
Monoprice Z-Wave sensor
This one does it all: temperature, humidity, motion and light. When the temperature changes by a specified amount, you'll get sent an alert - same with humidity. It's Z-Wave Plus, so you can use it as part of a Samsung SmartThings setup. Speaking of which, also consider Samsung's Multipurpose Sensor, which we mentioned earlier.
The second-gen Eve Room comes with a redesigned aluminum body and a high-contrast 1.54-inch E Ink display, which will tell you the temperature, humidity and air quality.
There are four different display layouts to choose from, and you can switch between them via touch panels on either side of the screen. The latest Eve Room has also done away with replaceable batteries in favour of a rechargeable one.