Keeping Your DFW Home Comfortable During the Holiday Season

December in Dallas-Fort Worth is genuinely unpredictable. It can be 70°F on Christmas Eve and 28°F three days later. It can snow, sleet, or produce a 10-day stretch of clear, cool weather. For your HVAC system, this variability means switching between heating and cooling modes multiple times in a single week — and the additional load of holiday guests, holiday cooking, and fireplaces all affect how your system performs.

Managing Heat Loads During Holiday Gatherings

A house full of guests adds significant heat load. Each person generates roughly 250 BTU/hr of body heat at rest — in a gathering of 15–20 people, that's 3,750–5,000 BTU/hr of added heat, which is meaningful relative to your home's total cooling or heating load.

Additionally, holiday cooking — especially with the oven at 350°F for several hours — can significantly raise kitchen temperatures. Range hood exhaust fans help, but heat still diffuses through the house. During large gatherings in December, your system may actually need to run in cooling mode briefly, even in winter.

Smart thermostat scheduling helps here. If you have a Nest or Ecobee, you can temporarily set a higher cooling setpoint and a lower heating setpoint (a wider dead band) so the system doesn't fight the gathering heat load — just modulates around it. This can save meaningful energy during multi-hour holiday events.

Guests Sleeping in Unused Rooms

If you have rooms that are normally unoccupied — a guest bedroom, a finished bonus room over the garage — you may find that they're uncomfortable for guests because the registers have been partially closed or blocked by furniture over the months they were unused.

Before guests arrive, open all supply and return registers in guest rooms and run the system in fan mode for an hour to equilibrate the temperature. Check that no furniture has been placed directly over floor registers or in front of wall vents. For bonus rooms over garages — notoriously difficult to heat and cool — a supplemental mini-split or portable heater may be more effective than fighting your central system's limitations.

Fireplaces and Indoor Air Quality

Wood-burning fireplaces add ambiance but can create indoor air quality challenges. Fireplace combustion draws air from the house (depleting the indoor air slightly) and, if the flue is poorly sealed when not in use, can allow cold outdoor air or residual smoke odors to infiltrate the living space.

If you use your fireplace over the holidays, make sure the damper is fully open when burning and fully closed when not in use. If you notice a persistent smoke smell in the house even when the fireplace is not being used, the damper may be deteriorating or the flue cap may need inspection.

Gas log fireplaces have similar considerations — confirm the pilot light is functioning and the burner produces a clean blue flame. A yellow or orange flame on a gas fireplace indicates incomplete combustion, similar to a furnace.

Freeze Protection During December Cold Snaps

DFW does occasionally experience hard freezes in December, and since Winter Storm Uri in 2021, DFW homeowners have become much more aware of the risk. For your HVAC system specifically: if you have a heat pump, do not manually switch it to emergency heat mode during a mild freeze — the heat pump is more efficient down to about 35°F and the emergency heat strips should only activate automatically when needed.

If temperatures are forecast below 20°F, let interior faucets drip slightly, open cabinet doors under exterior-wall sinks, and set your thermostat no lower than 65°F even if the house is empty. A frozen pipe inside a wall near the air handler can be catastrophic — preventing that scenario costs almost nothing.

The Best Holiday Gift for Your System: A Fresh Filter

If there is one thing to do before the holidays, it is to replace your air filter. A clogged filter going into December means your system starts the cold season at reduced efficiency, and if guests are staying over and the system is running frequently, that filter will clog even faster. A fresh filter takes five minutes and keeps your system running cleanly through the holiday period.