Smart thermostats, such as those from Honeywell and Nest, have become a popular - and, OK, smart - way of keeping homes not too hot and not too cold, saving both energy and money with their programmable and automatic functions.

But temperature control is only one part of your home's environment. At the Consumer Electronics Show (CES) in Las Vegas last week, a number of companies showed they are creating smart products to control other elements of your home's environment.

Clear the Air

Air purifier specialist Blueair, for instance, is exhibiting what it claims to be the world's first smart, fully connected indoor air monitoring, control and purification system. Blueair has combined its Sense+ air purifier and its Aware air monitor with its iOS or Android Friend app to create a "home defense system."

The app is more than just a control center, however. It gathers and delivers hourly updated data on local outdoor air quality from thousands of gauging stations across the U.S. to let you know what may be lurking outside. After identifying what's outside, Blueair's system can then eliminate 99.97 percent of the airborne allergens, chemicals or other pollutants that may have leaked into your abode.

Similarly, Coway is exhibiting its Airmega smart air purifying system, which claims to cleanse 99 percent of nasty things in the air, and will become available in March.

Airmega's app live-monitors your indoor pollution level and collects a 24-hour cross-section to a year's worth of data on your home's air condition. It also lets you know if you need a replacement filter, which you can buy from inside the app.

Standalone air purification systems are a good way to retrofit your home, but recent startup Keen Home lets you add air filtering to your existing duct system with its latest Smart Filters. These filters fit into Keen's smart vents, which can regulate temperatures room by room. In addition to real-time monitoring, the Works with Nest Keen app lets you know when the smart filters need replacing, and it can do so automatically with a subscription.

Environmental Safety

First Alert, the smoke and carbon monoxide alarm folks, are making an entire line of new Onelink products compatible with Apple's HomeKit and controllable by Siri.

For people who don't have a smart thermostat to interact with, the company is debuting its 3 by 2.8 inch white Onelink Wi-Fi Environment Monitor (available within the next three months), which sends alerts to an iOS device when the temperature and humidity shifts or if CO levels rise. You can even ask Siri to check the environmental status.

But you don't have to rely on alerts or Siri - the Monitor has an LED ring around the top: amber means the room is warmer than its preset level, blue means the room is colder, red warns CO levels are too high, and white means the room temperature is just right.

About the Author

Stewart Wolpin is a freelance journalist and longtime CES veteran. Stewart writes about consumer technology for eBay, where you can find all the latest electronic gadgets for your home.