December Home Maintenance Checklist: Mostly Holiday Safety

December ties with July as the lightest month on the maintenance calendar: check every cord and light strand before you plug it in, make sure the fireplace and any space heaters are safe to run hard, test the smoke and CO detectors, swap the furnace filter, and start watching the roofline for ice dams. Do those five things and you've done December.

The list is short because the stakes concentrate. No other month stacks fire risk like this one: a drying tree wrapped in lights, cords under rugs, candles, space heaters, and a fireplace at peak use. Our winter maintenance guide covers the season end to end; this page is only what matters right now.

Check the holiday lights and cords before anything goes up

The formal whole-house cord audit lands on January's list; December's version is triage for whatever comes out of storage. Before a strand goes on the tree or the eaves, run its length through your hands looking for fraying, cracked insulation, or crushed sections, then plug it in and feel the plug after a few minutes. Warm or damaged means retired.

Then check the connections. Outdoor lights need outdoor-rated cords on GFCI-protected outlets. Don't chain extension cords, and don't route them under rugs or through pinched door gaps. Cord count climbs fast in December, and a temporary cord that quietly becomes something's permanent power supply is one of the classic ways house fires start. An electrician adds an outlet for roughly $100 to 300 if the setup reveals you're short.

And if you have a live tree, water it daily; a dry tree burns shockingly fast.

Make the fireplace and space heaters safe to run hard

If you burn wood and the chimney hasn't been swept this year, call now and take whatever appointment you can get. Nearly every chimney fire starts in the creosote a sweep would have cleared out, and no month works the flue harder. Expect $150 to 350 for cleaning plus inspection of the flue, damper, and firebox.

A gas fireplace was due its annual inspection back in September or October; if that never happened, book it now. A technician checks the gas valve, pilot, and ignition for $100 to 250, and you can check the outside vent terminal yourself for nests, debris, or drifted snow. A blocked vent pushes carbon monoxide back into the house.

Space heaters get three rules and no exceptions: well clear of anything that can burn (curtains, bedding, the couch), plugged straight into a wall outlet rather than a cord or power strip, and off when you leave the room or go to sleep.

Test every smoke and CO detector

Press the test button on every smoke and carbon monoxide detector and confirm each one sounds. December stacks peak heating, peak cooking, candles, and a fireplace, so this is the month a dead unit costs the most. Working smoke alarms roughly halve your odds of dying in a home fire, and a CO detector is the only warning an odorless gas gives. A unit that stays silent with fresh batteries gets replaced; CO detectors age out every 5 to 7 years regardless.

Check the furnace filter and give the heat a once-over

With the system running long hours through one of the heaviest heating months of the year, check the filter even if it isn't technically due: 1-inch fiberglass filters are a monthly habit, 1-inch pleated ones go 2 to 3 months, and thick media filters last 6 to 12. The swap is $10 to 30; the skip is higher bills, a strained blower motor, and a system that overheats when airflow chokes. The HVAC maintenance schedule covers the full year.

Two system-specific checks while you're at it:

• Heat pump: on cold days, watch the outdoor unit for a few minutes and confirm it clears its own frost. Periodic defrosting is normal; a unit encased in ice is not, and running it that way risks the compressor.
• Boiler: confirm the pressure gauge reads 12 to 15 psi, check the sight glass water level, and bleed any radiator that gurgles or stays cold at the top.

Use the first snow to learn your roof

In zones 4A/4B and 5 through 8, the first snowfall that sticks is a diagnostic you get once a year. A healthy roof holds an even blanket that shrinks slowly and drains cleanly off the edge. A roof with an attic heat leak melts in patches: bare streaks appear high up while the eaves stay white, and by the second week of snow cover the meltwater refreezing over those cold eaves thickens into a ridge of ice.

That baseline is the whole December job; the insulation and ventilation fixes belonged to fall, and full damage-control mode is a January concern. If a ridge is forming now, a roof rake pulls the snow feeding it off the lower few feet of roof from the ground. Hardened ice means professional removal at $300 to 800. Zones 5 through 8 carry the engine's highest priority here; zones 1 through 3 and marine 4C skip this section entirely.

Ten-minute extras if you have the time

• Brush off the gutter guards, if November's cleaning skipped them. Late leaves and pine needles pile on top of the mesh and dam water over the edge, exactly what the guards were meant to prevent. A soft brush or blower clears them in 30 to 60 minutes, versus $75 to 200 for a service; zones 5 through 8 are on a twice-a-year cadence because foliage piles up faster.
• Clean the dishwasher before the holiday cooking marathon. Rinse the filter, clear the spray arm holes, and run an empty hot cycle with two cups of white vinegar. Twenty minutes, $3 to 8, and clean glasses instead of explaining the smell to your guests.
• Run a radon test. Radon builds up while the house stays closed, so a December test catches levels near their annual peak, which is the number that matters. A charcoal kit is $15 to 30, sits for 48 hours, and a result at 4 pCi/L or above means calling a mitigation pro.

Living somewhere warm? Your December is outside

In hot-humid zones 1 and 2 (Houston and south), pests never take a winter break, and the schedule reflects it: the perimeter treatment tightens to roughly every two months there, versus quarterly in milder climates. It's an insecticide barrier at the foundation and vegetation trimmed a foot off the walls, 30 to 45 minutes and $15 to 40 DIY or $75 to 150 for a service. Mild-winter zones also get the year's best tree-trimming weather: cut branches back to 10 feet from the roof and 3 feet from siding, and remove anything dead over the house. Count on 1 to 3 hours yourself or $200 to 800 for a crew.

Common questions

Is it safe to leave holiday lights on overnight?

Interior lights on a live tree, no; a dry tree plus warm lights plus nobody awake is the classic December fire scenario. Exterior LEDs on outdoor-rated cords are lower risk, but an inexpensive outlet timer removes the question for both.

I only use the fireplace a few times each winter. Do I really need a sweep?

You need at least an inspection. Creosote accumulates by the fire, not by the calendar, but cracked flue liners, failed dampers, and animal nests don't care how often you burn. The inspection also tells you whether the full cleaning can wait.

How do I know if ice on my roof edge is actually a problem?

Icicles alone aren't a verdict. A continuous band of ice at the eave, ice creeping upslope from the roof edge, or fresh stains on upstairs ceilings near exterior walls all mean water is pooling behind ice, and it's time for a roof rake or a removal call.

A short month is the easiest one to skip entirely, which is how the fireplace goes unswept for a third year. SeasonKeep turns this into dated reminders built from your zip code and systems in about three minutes, free to start, and the January checklist picks up where the holidays leave off.