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| Using your heat pump in the summer cools your home by pulling heat and humidity out. To keep it running efficiently, avoid sudden thermostat changes, let the fan run on auto, and ensure airflow around your outdoor unit stays clear. |
Did you know that heat pumps are one of the most efficient HVAC systems for year-round indoor climate control? They transfer heat from one place to another. When you switch to cooling mode, they keep you feeling cool and fresh by pulling warm, humid air out of your space.
Considering the recent heat warnings in Ontario, it’s more crucial than ever to optimize your heat pump settings for summer. Even minor misconfigurations can make your space muggy. Here’s how to maintain comfortable air quality all season without driving up your energy costs.
At a basic level, a heat pump operates through heat transfer. Unlike conventional air conditioners or cooling systems, it doesn’t just blow cool air into your space.
Its refrigerant coil extracts heat and moisture from your indoor air, then the outdoor unit compresses and transfers them to the outside air. It’s a closed-loop process that works in both ducted and ductless systems.
Heat pumps switch refrigerant flow by activating the reversing valve. There’s no need to press a button on the unit itself. It’ll automatically switch between warm and cool air based on the temperature set on your thermostat.
In cooling mode, the indoor coil functions as the evaporator, while the outdoor coil releases heat. Alternatively, heating mode reverses the refrigerant flow. The outdoor coil becomes the evaporator, while the indoor coil acts as the condenser. This internal switch is managed entirely by two central components: the system logic and the reversing valve.
Learn more: How Heat Pumps Work
You can maintain comfortable indoor air quality and stay energy efficient by managing how your heat pump runs.
The typical runtime depends on what type of heat pump you have. Variable-capacity systems use an inverter-driven or variable-speed compressor to adjust their output to match the preferred temperature. They run longer at lower speeds to match cooling demand.
Meanwhile, non-inverter (single-stage) heat pumps and traditional air conditioners are designed to operate in shorter on/off cycles. They run at full power and then shut off after hitting the target temperature. Once you know your system’s ideal runtime, adjust your use accordingly.
During summer, a heat pump’s indoor coil also acts as a dehumidifier. But this only works effectively during longer cooling cycles, when moist, warm air spends enough time passing over the coil. If the system short-cycles too often, indoor humidity can stay high even if the room feels cool.
To improve dehumidification, avoid adjusting your thermostat up and down throughout the day. Instead, follow a consistent setpoint.
Your outdoor unit expels heat during cooling mode, and its efficiency depends on unrestricted airflow. Walls, fences, plants, or stacked objects can block airflow. And when heat builds up around the coil, the system increases its energy use to maintain peak performance.
Make sure your outdoor unit has ample space on all sides. Avoid surrounding it with plants, furniture, or storage bins that could block airflow.
Professionally installed systems are positioned with clearances based on manufacturer specs (often 30 to 60 centimetres on all sides). However, airflow can still be disrupted over time by overgrown shrubs or backyard clutter. Keeping the area open helps the system release heat efficiently, especially in tight spaces like patios or alleys.
Leaving the fan set to “on” can unintentionally push warm air back into your living space. When the compressor shuts off, residual heat from the indoor coil and ductwork may linger. The stagnant air might make your space feel warmer and potentially trigger more compressor cycles.
To prevent this, sync fan activity with the cooling cycle. Air only moves when the system is actively lowering the temperature, keeping airflow sharp and purposeful.
It’s normal to feel warmer at night as stored heat from walls, floors, or attics radiates back into the living space. Called thermal lag, this delayed release of heat can make you think the room is warming up and prompt you to adjust the thermostat at night. However, that often backfires by triggering longer, high-output compressor cycles just as outdoor temperatures begin to cool.
For inverter-based systems, sudden temperature drops can disrupt low-speed operation and force an output surge. Short bursts of cooling will cause temperature swings and overcorrect. The best approach is to let the system manage the remaining heat load gradually.
Calibrate your thermostat for optimal performance and energy savings based on outdoor temperatures. Here’s how to get the best temperature for a heat pump in summer.
trUnoccupied (long-term)Set to 28 °C or use vacation modeMaintains airflow and prevents excess humidity buildup (don’t turn off the system)
| Scenario | Setting | Technical Reason |
| Occupied (daytime) | 22 to 24 °C | Balances cooling load and humidity control while supporting longer compressor cycles |
| Occupied (nighttime) | Same as daytime, or lower by 0.5 to 1 °C | Allows steady cooling overnight and prevents compressor ramp-ups |
| Unoccupied (short-term) | Raise by 3 to 5 °C from active setpoint | Reduces system load while keeping humidity in check |
| Typical everyday user preference (based on online forums) | 20.5 to 21 °C | Common in older homes or poorly insulated spaces |
| Smart thermostat | Dynamic schedule with 0.5 to 1 °C shifts | Enables gradual setpoint adjustments and adaptive cooling during heatwaves |
Keep your HVAC system running properly throughout the hot and humid months with these helpful tips.
Don’t rush to tweak the thermostat if certain parts of your indoor space feel warmer (or colder) than others. Inconsistent airflow could reveal issues inside the ductwork, like a partially blocked return vent.
However, it could also point to an early warning sign of pressure imbalance. If the issue persists, have a licensed HVAC technician inspect your system to pinpoint the cause and prevent long-term damage.
Check the insulated copper line running from your outdoor unit. When your system is in cooling mode, it should generally feel cold, like a chilled can of soda. If it’s warm or room temperature, that could indicate:
The reversing valve makes a few noises when starting up. You’ll usually hear a soft click when the solenoid engages, a whooshing sound as the internal pressure shifts, and a slight pause in compressor noise. They usually last a few seconds.
However, note anything loud and repetitive. Rapid toggling between modes, persistent clicking, and a loud metallic clank typically suggest underlying damage. In these cases, call for an inspection.
The indoor coil removes moisture from the air and drains it into a shallow pan underneath. Collected water flows out through a dedicated condensate drain line. It might be backed up if you see water pooling around the air handler or notice damp spots on the floor below the unit. In that case, ask your HVAC technicians to check for algae, dust, or mould.
Whether you’re optimizing your heat pump settings for summer, scheduling routine maintenance, or considering a new heat pump installation, our team is ready to help. LG Home Comfort offers same-day appointments in Southern Ontario. We have licensed, fully equipped HVAC technicians on standby 24/7. Get in touch with us for a sample quote and estimate.
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