Dear Jim: We have a new gas furnace in our home with direct-vent sealed combustion. The design seems very safe. Is it really necessary to spend still more to get carbon monoxide detectors for our home? – Ken M.

Dear Ken: You should absolutely have CO detectors in a home which uses any type of combustion appliances. Even though new sealed combustion gas furnaces are much safer than older designs when it comes to possible CO poisoning, it is always better to be safe than sorry later. If you have a gas furnace, you likely also have a gas water heater and range.

CO gas kills almost 500 people and makes more than 15,000 people ill each year. The most frightening characteristic of CO is it is odorless, colorless and tasteless so your body cannot detect it. Unborn babies, infants, and people with heart and respiratory disease are most susceptible to CO. The early symptoms of CO poisoning are similar to the flu – nausea, dizziness, fatigue, vomiting, etc. When there is a malfunctioning heating appliance in a home, the CO level builds up over time. Without a CO detector, if your children feel these flu-like symptoms, you may just send them to bed to rest while the risk still is increasing.

Since the majority of CO problems occur from heating systems, it is wise to install a CO detector near them in the utility area or basement. This will provide the earliest warning of problems before the CO concentrations get to dangerous levels in the rest of the house. Also install at least one, and preferably several, in the sleeping areas of your home. If CO levels rise while you are sleeping, you will not be aware of the flulike symptoms and it may be fatal. Also, it is usually colder at night, so the furnace runs more and produces more CO if there is a problem. The newest designs of CO detectors communicate with one another. If the one near the furnace senses high CO levels and sounds, someone, especially the elderly, may not hear it in a bedroom. These communicating models sound all the detectors when any of them senses CO.

The alarm signal also sweeps through high-low frequencies because the elderly often lose their ability to hear high-pitched tones. The best models have built-in memory to record the highest CO level. This information can be helpful to emergency personnel to determine the best treatment. For convenience, consider using an alarm clock with a built-in CO detector by your bed. Another CO detector design can be controlled with any television remote. This allows you to easily silence the alarm as you leave the house. This eliminates the hazard when someone removes the battery to silence it and forgets to put it back in later.

The following companies offer carbon monoxide detectors: First Alert, (800) 323-9005, www.firstalert.com; Kidde, (800) 880-6788, www.kiddeus.com; North American Detectors, (800) 387-4219, www.nadidistribution.com; Research Products, (888) 257-8801, www.aprilaire.com; and S-Tech, (800) 203-7987, www.ppi-stech.com.

Send inquiries to James Dulley, Bangor Daily News, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com.