Short Cycling In Heat Pumps: Is The Thermostat To Blame?

Residential heating systems that use air-source or geothermal heat pumps are becoming an increasingly popular alternative to conventional furnaces. These cutting-edge heating systems are prized for their energy efficiency and low running costs.

Most heat pump-based heating systems are also very reliable. Unfortunately, they can still suffer from mechanical problems from time to time, and a phenomenon known as 'short cycling' can be particularly troublesome to deal with.

What Is Short Cycling In Heat Pumps?

Short cycling occurs when a heating system activates, only to automatically deactivate itself a short time later, sometimes before any useable heat has been generated. Short cycling can affect all kinds of residential heating systems, and heat pumps are no exception.

Short cycling can undermine your heat pump's ability to produce enough heat and can lead to a very chilly home during the winter months. Activating and deactivating frequently also uses significantly more power than continuous operation, and can cause electrical components and moving parts to wear out more quickly, increasing your heat pump's energy consumption and maintenance costs.

How Do Thermostats Cause Short Cycling In Heat Pumps?

Faulty thermostats are a common cause of short cycling in heat pump-based heating systems. If your system is short cycling, checking the thermostat should be your first priority.

In some cases, short cycling can occur because the thermostat was not installed in a suitable location. If your thermostat is located close to a heating duct, or an area in direct sunlight, the temperatures registered by the thermostat may be significantly hotter than the average temperature inside your home.

This can cause the thermostat to reach its assigned temperature and deactivate the heat pump before your home has been brought up to temperature, leading to short cycling. In these cases, you should have the thermostat relocated and reinstalled by a professional heating repair service.

If thermostat placement isn't an issue, the thermostat itself has probably malfunctioned. Electrical faults, such as burnt-out temperature sensors or faulty wiring, can cause the thermostat to send rapid activation and deactivation signals to the heat pump. The faulty thermostat will need to be professionally repaired or replaced.

Can Other Problems Cause Heat Pump Short Cycling?

While thermostat issues are a common cause of heat pump short cycling, they are not the only potential cause. Short cycling can also occur if your heat pump is overheating due to damaged or blocked air filters. The problem may also be caused by a faulty electrical control board inside the heat pump itself. It is generally easier and safer to call in a professional heating repair service to diagnose and fix the underlying cause, rather than trying to fix the problem yourself.

Be sure to contact professionals if you need residential heating maintenance of any kind.