Individual Carbon Monoxide Detectors May Be A Better Choice Than Combo CO/Smoke Detectors
If you have gas appliances in your home, such as a gas heater, a carbon monoxide (CO) detector is a must -- in fact, it's required by law in some states. This has led to the development of many different styles of CO detector, including dual CO/smoke alarms. Those seem really handy, and they can be, but sometimes getting a separate CO detector is better. It really depends on the size of your home and the level of convenience you want.
Location and available space are actually on the side of the combo detector. If you live in a small place, like a small studio, having multiple detectors can look kind of messy, even though these are small and relatively unobtrusive. Using one detector that covers both CO and smoke can be a lot more convenient for you. However, if you live in a bigger home, then the lack of space isn't so much of a concern.
Each brand of detector has its own styles of beeps for low battery warnings, CO warnings, and so on. Some may be louder than others. You might also already have smoke detectors that are wired into your home's electrical system (as opposed to being solely battery-run), and replacing those with another style of smoke detector might not be high on your agenda. In these cases, adding a separate CO detector is the way to go -- there's no need to change the home's existing smoke detector.
Repairs and Breakdowns
As with any multi-purpose appliance, if one of the functions on a combo detector breaks down, you could find the other functions not working properly either. In other words, if your combo detector breaks, you've lost both your CO and your smoke detector. If you keep them separate, you're not going to have to replace both if one decides to go.
Note that even if you don't use the heater and have no other gas appliances, CO is still a risk. Any time you have a gas line running into your home, you have to be on the lookout for CO. You should get a detector as soon as you can.
You may want to speak with a heating contractor about what he or she prefers to use. Gas heating and other gas-fueled appliances should not be used without a CO detector in the home, so the contractor should be familiar with the different types available. Contact a company like Bill Rhiner's Plumbing, Heating & Cooling to learn more.