TEND TO THE FIREPLACE

Close the flue in your fireplace when it’s not in use. “It’s amazing how many houses I go into in winter and think, ‘It’s really cold in here,’ and the flue’s open,” Rex says. He recommends putting a sticky note on your fridge on nights you have a fire. That way, in the morning, you’ll remember to close the flue.

Even when the flue is closed, it’s not a snug seal, so it’s still a heat-loss point. The best way to keep your fireplace airtight is to have a contractor install a glass door with vents at the bottom. “It’s energy-efficient, and you still have the comfort and ambience of a fire,” says Rex.

CHECK YOUR HEATING SYSTEM

In homes with forced hot-air heating, it’s important to change the filters annually. If the ductwork in your basement or attic is coming apart at the seams, seal it up so heat cannot escape — but don’t use duct tape. “Ducts are the only thing you do not use duct tape on,” says Kimbel. “It gets crisp and brittle and falls off. Use metal-foil tape instead.” Ducts do need to be sealed, Rex adds, but “much more frequently I’m finding gaps in the registers.” He recommends removing the vent cover and using spray-foam insulation like Great Stuff to close cracks between the ductwork and flooring, walls, or ceilings.

If your ducts haven’t been cleaned in 100 years, now might be a good time to do that, too. Angie’s List can put you in touch with 267 companies that professionally clean air ducts in the Boston area, 39 of which are “top-rated.”

According to Hicks, maintaining your furnace or boiler should be a priority. “The most common reason for emergency calls,” she says, “is failure to do maintenance in the fall. A furnace tuneup is only $75 or $100.” Realtor Gabrielle Daniels, with Coldwell Banker in Sudbury, agrees. “It’s a phone call to your heating company,” she says. “They will come out and service it properly, replacing any missing parts or fixing anything that’s broken, so it’ll operate most efficiently during the winter. Emergencies happen on Friday at 5 o’clock, but if you make that call, you might lessen the possibility.”

For boilers, consider asking the technician to install a reset heating control, which can increase efficiency by differentiating between colder and milder weather. It costs from $300 to $400 but can save as much as 10 percent on your heating bill. National Grid offers a $225 rebate on such a device, but you must obtain a “Web Submission ID” number from the utility’s website before installing it.

Daniels also urges you to use your winter tune-up time to change the batteries in your smoke and carbon monoxide detectors.

All of our experts advise getting an EnergyStar programmable thermostat if you don’t already have one; it can automatically turn the heat down while you’re out of the house. For installations made before January 1, 2013, Mass Save, an initiative sponsored by the state’s electric and gas companies to help residents and businesses manage energy expenses, offers a $25 rebate, and with the cost of most models under $60, says Spinelli, “you’d probably get your money back in the first year.” It’s a simple thing to do, involving only two or three wires, and at least one manufacturer, Honeywell, “provides a phone number you can call, and they will hold your hand through the whole process,” says Kimbel.

LOOK AFTER WATER SYSTEMS

Like the furnace or boiler, your hot water tank should be checked before you go into winter, but in this case you can do it yourself. If the thermostat is set at more than 120 degrees — the safety point that can keep children and the elderly from being scalded — turn it down. “Instead of finding your perfect shower temperature by mixing overly hot water with cold at the tap,” Rex says, “just set your hot water heater so it comes out at the right temperature.” According to the Environmental Protection Agency, this simple fix can save you from 6 percent to 10 percent on your water-heating costs.

Rex and Kimbel also point out, perhaps surprisingly, that buying a “blanket” to put around the hot water tank is not a good return on investment unless your tank is more than around 15 years old. “If you put your hand on it and it feels warm,” says Kimbel, “it’s worth putting the blanket on. But the new EnergyStar heaters have better insulation and don’t need it as much.”