CHICOPEE, Mass. (WWLP)-- Fire officials are reminding people of the importance of having working carbon monoxide alarms in their homes after a Massachusetts family died from CO poisoning on Christmas Day. In Massachusetts alone firefighters receive about 5,000 calls a year addressing high levels of carbon monoxide, most of them during the winter months. Four found dead Christmas Day in New Hampshire home "We can't see it, we can't smell it, we can't taste it. And that's why it's often called an invisible killer and that's why it's so important that we have working carbon monoxide alarms on every level of our homes," said Jake Wark, the public information officer for the Massachusetts Department of Fire Services. "If your carbon monoxide alarm goes off, get outside, get some fresh air, call 911." The gas is poisonous to both people and pets. As temperatures drop you're going to want to heat your home, but you need to make sure your furnace is working properly and you have working carbon monoxide detectors on every floor of your house. Testing alarms once a month is recommended, and replacing batteries twice a year during time changes. One woman 22News spoke with said she experience CO poisoning last winter after buying a new furnace for her home. "And little did we know that the um chimney was collapsing inside because it couldn't handle the strength of the new furnace," said Gardner resident Marian Hagopian. Carbon monoxide entered her home, setting off the CO alarms and saving her life. "Another issue that we encounter in the winter time is when snow falls and snow drifts block the vents from your furnace or your dryer or other appliances," said Wark. Keep those areas clear and avoid shoveling or blowing snow on them to prevent trapping carbon monoxide. Massachusetts state law requires a CO alarm if you have any kind of fuel burning in your home. It's a good idea to have your furnace inspected annually by an HVAC specialist.