Heat Pumps and Auxiliary Heat: When and How to Use Them
A heat pump can run while on auxiliary heat, but whether it should depends on several factors. This article explores the conditions and considerations to ensure optimal energy efficiency and comfort.
Temperature Conditions
Auxiliary heat is typically activated when outdoor temperatures are too low for the heat pump to operate efficiently. In such cases, the heat pump may still run to provide some heating. However, the auxiliary heat, often electric resistance heat, will supplement the heat pump to maintain the desired temperature.
Efficiency
Running both the heat pump and auxiliary heat can lead to higher energy consumption. It is usually more efficient to rely on the heat pump alone when conditions allow. Ensuring the heat pump is kept in optimal working condition is key to maintaining this efficiency, as it can save you a significant amount of money on your electricity bills.
System Design
Some heat pump systems are designed to use both sources of heat simultaneously for faster heating, especially in very cold conditions. However, this depends on the system design. For example, if the heat pump is experiencing difficulty keeping up with the temperature requirement, the auxiliary heat strips will kick in to assist the heat pump. This is crucial in maintaining adequate warmth when outdoor temperatures drop significantly.
Thermostat Settings
Your thermostat plays a crucial role in managing the balance between the heat pump and auxiliary heat. Setting it appropriately can help minimize energy waste and ensure that the heat pump and auxiliary heat work in harmony. If your thermostat is set too closely, it can sometimes cause both heat sources to activate simultaneously, leading to inefficiency and unnecessarily high energy costs.
When and Why to Use Auxiliary Heat
While a heat pump is designed to operate efficiently in moderate temperatures, it reaches its efficiency optimal point around 40°F (4°C) to 45°F (7°C). Below this temperature, the heat pump’s performance can drop, leading to higher electricity costs. Auxiliary heat, including electric resistance heat, serves as a complement to the heat pump during these colder months.
Defrosting and Auxiliary Heat
Another role of auxiliary heat is in the defrost cycle of a heat pump. During the defrost cycle, the heat pump switches to cooling mode to melt any ice buildup on the outdoor coil. Auxiliary heat helps warm up the air that blows during this process, ensuring the indoor temperature does not drop too much during the defrosting cycle.
Thermostat Configuration
Some advanced thermostats can handle the staging of heat pump and auxiliary heat automatically, whereas more basic thermostats may require manual intervention. For instance, if your thermostat is set to automatically switch to auxiliary heat, you should ensure that the heat pump remains on as it is the primary heating source. However, if your thermostat is set to Emergency Heat, the supplemental heat strips will kick in, and the heat pump will shut off.
Energy Efficiency Considerations
It's important to note that auxiliary heat, such as resistance heat coils, can be more expensive to run than the compressor. This is because resistance heat requires a significant amount of electricity to generate heat. The compressor, on the other hand, is usually more efficient at converting electrical energy into heat energy.
Conclusion
While a heat pump can run with auxiliary heat, it's crucial to consider efficiency, system design, and specific heating needs at the time. Proper thermostat settings and system configurations can help maximize the efficiency and performance of your heat pump system, ensuring that it operates optimally in a wide range of temperature conditions.
Understanding the role of auxiliary heat and how to use it effectively can save you money and improve your home's comfort. If you have any questions or need further assistance, consider consulting a professional for guidance.