Aircon in Winter: Heat & Save



Introduction

Modern air conditioners are not just for summer. Most domestic and commercial units are heat pumps that deliver heating, humidity control, and lower running costs throughout the colder months. Below we explain how to get the most from your system in winter — and why it’s often more cost-effective than direct electric heaters.

Why an Air Conditioner Helps in Winter

1) Efficient Heating (Heat Pump Technology)

A heat-pump AC moves heat from outdoors to indoors. For every 1 kW of electricity it uses, it can deliver around 2.5–4 kW of heat (model and outdoor temperature dependent). That efficiency ratio (COP/SCOP) is why AC heating is typically cheaper to run than fan heaters or electric convectors, which only provide 1 kW of heat per 1 kW consumed.

Advantages

• Fast warm-up and stable target temperatures

• Zoning: heat only the rooms you use

• Quiet, efficient inverter compressors

2) Dehumidification: Tackling Moisture and Condensation

Winter humidity often causes condensation on windows, damp patches and mould. In Heating and Dry modes an AC helps maintain a comfortable 40–55% RH, lowering mould risk and improving comfort. Slightly drier air also feels warmer at the same thermostat setting.

Signs you need dehumidification

• Morning window fogging

• Musty smells, cold corners, visible damp

• High humidity in bedrooms and kitchens

3) Real Savings on Electricity

Thanks to a higher COP, a heat-pump AC provides more heat per kWh than direct electric heaters. Smart features (timers, weekly schedules, occupancy sensors) avoid heating empty rooms and enable night setbacks to trim bills without losing comfort.

How to Use Your AC in Winter (Best Practices)

Modes and Setpoints

• Heating: keep 20–22 °C by day, 18–19 °C at night

• Dry: use if windows fog or you spot damp; avoid over-drying

• Auto/Eco: useful during stable weather

Fan & Airflow

• Start at Low/Auto for even heat; increase speed only for quick warm-up

• Direct airflow along the ceiling so warm air spreads without blowing on occupants

Timers & Schedules

• Night setback: drop 1–2 °C overnight to save energy

• Pre-heat: start 15–30 minutes before you return home

Ventilation & Humidity

• Short, sharp airing (5–7 minutes) with the unit off, then resume heating

• Aim for 40–55% relative humidity

When Efficiency Is Highest

• Insulation & glazing in good condition

• Airtightness: fewer uncontrolled draughts

• Regular maintenance: clean filters and coils keep COP high

FAQs

Will it heat in sub-zero temperatures?
Yes — many inverter models maintain useful output below 0 °C (limits vary by series). Expect periodic defrost cycles; that’s normal.

How much can I actually save?
Switching from direct electric heat to a heat-pump AC with COP ≈3 can halve or even third the cost per unit of heat, plus extra savings from zoning and schedules.

Does AC over-dry the air?
In Heating mode most homes find humidity lands in a comfortable range. If air feels too dry, raise target humidity (if available), reduce fan speed, or ventilate briefly.

Can I heat just one room?
Yes — that’s the point of zoned heating with single or multi-split systems.

Practical Money-Saving Tips

• Smart controls: weekly schedules, occupancy sensors, remote control

• Filter care: clean every 2–4 weeks in season

• Seal gaps: draught-proof windows/doors

• Window coverings: close curtains/blinds at night to reduce heat loss

• Stable setpoints: small, steady adjustments beat large daily swings

When to Consider an Upgrade

• The unit is 8–10+ years old and struggles in cold weather

• Noticeably louder operation or rising bills

• You want Wi-Fi controls, geofencing or a quieter night mode

Conclusion

In winter an air conditioner acts as an efficient heater, a humidity controller, and a bill-saver. With sensible setpoints, clean filters and basic insulation, you’ll enjoy steady comfort and lower costs. Size the unit correctly, use Heating/Dry as needed, and put schedules to work around your routine.