AOS Blog
What Is Heat Pump Cycling and Why Does It Matter?
Heat pumps are an energy-efficient way to heat and cool your home, but their performance depends on how well they cycle. Heat pump cycling refers to how often the system turns on and off to maintain a steady temperature. If your heat pump is cycling too frequently (short cycling) or running non-stop, it may not be operating as efficiently as it should.
In this blog, we’ll explain how heat pump cycling works, the common causes of cycling problems, and what you can do to keep your system running smoothly.
How Does Heat Pump Cycling Work?
A heat pump should run in regular cycles, meaning it turns on, heats (or cools) your home, and then turns off once the desired temperature is reached. The system will then restart when the temperature drops or rises beyond the set point.
A properly sized and installed heat pump should cycle about 2-3 times per hour, with each cycle lasting 10-20 minutes in moderate weather. However, extreme temperatures may cause longer run times, which is normal.
Types of Heat Pump Cycling Issues
1. Short Cycling (Turning On and Off Too Often)
Short cycling happens when a heat pump shuts off too quickly and then restarts within a few minutes. This not only reduces energy efficiency but also increases wear and tear on the system.
Common Causes of Short Cycling:
• Oversized Heat Pump – If the heat pump is too powerful for your home, it will heat or cool too quickly and shut off before running a full cycle.
• Clogged Air Filters – A dirty filter can restrict airflow, causing the system to overheat and shut off prematurely.
• Low Refrigerant Levels – If there’s a refrigerant leak, the heat pump may struggle to absorb or release heat properly, leading to short cycling.
• Thermostat Problems – A faulty or poorly placed thermostat (e.g., near a heat source or in direct sunlight) can cause the system to misread temperatures and turn on and off too frequently.
2. Continuous Running (Not Turning Off)
In some cases, a heat pump may run non-stop without cycling off. While this can be normal in extremely cold weather, it may indicate an issue if it happens in moderate temperatures.
Common Causes of Continuous Running:
• Undersized Heat Pump – If the unit isn’t powerful enough for your home, it will struggle to reach the desired temperature and run constantly.
• Poor Insulation – Heat loss through walls, windows, and doors can cause the system to work overtime to maintain warmth.
• Thermostat Set Too High/Low – If the thermostat is set too high in winter or too low in summer, the system will keep running to try to reach the target temperature.
• Faulty Sensors or Controls – If the heat pump’s internal sensors are not working properly, it may not recognise when to shut off.
Why Heat Pump Cycling Matters
Whether your heat pump is short cycling or running continuously, both issues can lead to:
✔️ Higher Energy Bills – Frequent cycling or extended run times waste electricity.
✔️ Reduced Comfort – Short cycling causes uneven heating, while continuous running can lead to excessive humidity in summer.
✔️ Increased Wear and Tear – Components such as compressors and motors wear out faster, leading to costly repairs or early system failure.
How to Fix Heat Pump Cycling Issues
If your heat pump is cycling too frequently or running constantly, here’s what you can do:
✅ Check and Clean the Air Filters – Dirty filters restrict airflow and can cause overheating. Replace them every 1-3 months.
✅ Inspect the Thermostat – Ensure it’s properly placed and functioning correctly. If it’s outdated, consider upgrading to a smart thermostat for better control.
✅ Seal Any Air Leaks – Check windows, doors, and walls for drafts, and improve insulation to reduce heat loss.
✅ Schedule a Professional Inspection – If you suspect your heat pump is oversized, undersized, or low on refrigerant, contact a qualified heat pump installer like AOS Energy Efficient Heating Systems for a professional assessment.
Conclusion
Heat pump cycling is an important factor in how efficiently your system operates. A properly sized and maintained heat pump should run in steady cycles to provide consistent comfort, lower energy costs, and extend system lifespan.
If your heat pump is short cycling, running continuously, or not performing as expected, the team at AOS Energy Efficient Heating Systems can help. We specialise in heat pump installation, maintenance, and repairs in Cambridgeshire, South Bedfordshire, Hertfordshire and Buckinghamshire, ensuring your system runs as efficiently as possible.
Contact us today to schedule a consultation and keep your home comfortable all year round!
