Understanding the Role of Heat Pumps in Mild Winters
Heat pumps are part of your home’s HVAC system. They can work like an air conditioner cooling your home, but the same unit can be used to heat your home during the winter. Heat pumps use electrical power. They do not create heat, nor do they create cold. Instead, they transfer heat from one place to another, keeping your home comfortable all year round. Because of their heating and cooling capabilities, heat pumps can replace a furnace and air conditioner.
Heat Pump Types
The two most common types of heat pumps are air source and ground source. As the name suggests, an air source heat pump transfers heat between outdoor air and indoor air. This type is widely favored for heating and cooling residential units.
On the other hand, a ground source heat pump transfers heat between the indoor air and the ground outside. Throughout the year, at depths exceeding 30 feet below the surface, soil temperature remains relatively constant. In Sacramento, the ground temperature at this depth ranges between 60 and 65 degrees Fahrenheit. While ground source heat pumps may have a higher installation cost, they boast increased efficiency and maintain a consistent temperature year-round, irrespective of external weather conditions.
Basic Heat Pump Principles
A furnace creates heat by burning fuel or using electrical energy. During the summer, a heat pump will pull heat energy from the air outside, even if the temperature is cold. It transfers the heat from outside to inside the home. When the heat pump is in cooling mode, it does the reverse. It pulls the heat from inside the building and transfers it outside.
The outdoor unit of the heat pump has a coil and a fan. When the heat pump is in heating mode, the outdoor coil is an evaporator coil. The outdoor coil is a condenser coil when it is in cooling mode. The fan blows outside air over the coil to create heat exchange.
The indoor unit can also be an evaporator coil or condenser coil, depending on how the system is being used. The fan in the indoor unit moves air across the coil, distributing heated or cooled air in the home.
Refrigerant is what absorbs and ejects heat as it circulates through the heat pump. The compressor puts the refrigerant under pressure, pushing it through the system. A reversing valve is what dictates the flow of the refrigerant. This allows the heat pump to serve as a cooling or heating device. The expansion valve regulates the flow of the refrigerant, allowing for the pressure to reduce and changes in the temperature of the refrigerant.
How a Heat Pump Heats the Home During the Winter
A major question is, how can a heat pump heat a home by transferring heat from outdoors if the outdoor temperature is cold? Even when outdoor temperatures are low, some heat is always in the air. The heat energy outdoors is absorbed by the cool liquid refrigerant. This refrigerant has a very low boiling point, so it is turned into a cold gas. Pressure is then applied to the gas, making it a hot gas. The hot gas travels to the indoor unit, and the blower pushes air over the indoor coil. The refrigerant is cooled, it is relieved of pressure, it’s transferred to the outdoor unit, and the cycle begins anew.
Heat Pumps Are Most Effective at What Outdoor Temperatures?
A heat pump’s effectiveness depends on your location’s temperature range. Sacramento, California, experiences winter temperatures ranging between 40 and 65 degrees. Air heat pumps generally lose efficiency when temperatures fall below their specified range. For air source heat pumps, efficiency decreases when the temperature drops below -13 degrees. Geothermal systems show more resilience in extremely cold weather but perform optimally within a temperature range of 40 to 75 degrees. Other factors, aside from outdoor temperatures, can impact the effectiveness of your heat pump during winter.
Low Refrigerant Levels
Refrigerant is essential for heat pumps to transfer heat between locations. Insufficient refrigerant levels can impede heat transfer, leading to suboptimal performance and cooler temperatures. Resolving this issue requires contacting an HVAC technician.
Dirty or blocked filters can diminish the effectiveness of your heat pump. Clogged filters force the heat pump to work harder, lowering temperatures. Maintaining or replacing air filters is crucial for optimal performance. Periodic checks and timely replacements are necessary.
Faulty Thermostat Settings
Incorrect thermostat configurations can pose challenges for your heat pump in determining the desired home temperature. An HVAC technician can ensure proper adjustment of all settings and offer troubleshooting options to optimize your heat pump’s performance.
Why Mild Climates Are Best for Heat Pumps
Heat pumps can work in cold climates like those found in northern states. But they need to be chosen carefully and properly installed.
That being said, with a heat pump, heat losses are proportional to the difference between indoor and outdoor temperatures. Heat pumps have a balance point where they can produce their highest heat capacity. For many heat pumps, 47° is the common heat pump rating point. As the outside temperature drops, the heating capacity of the heat pump goes down. Heat pumps are more popular in the south or southwest, where temperatures rarely go below freezing. The milder winters ensure that the heat pump can efficiently pull enough heat from the outdoor air and transfer that heat into the home without using excessive amounts of energy and without leaving the home feeling unnecessarily cold.
Should Those Living in Colder Climates Consider a Heat Pump?
That being said, individuals living in colder climates should not completely rule out a heat pump as a heating option for their home. Heat pumps have gotten a lot better since they were invented. High-performance models are capable of handling some of the coldest temperatures that winter can deliver.
Newer heat pumps have redesigned compressors, super efficient fans, improved coil designs, and better motors. The compressors on newer heat pumps can adjust their speed and energy consumption to meet the dips in the temperature. The use of grooved copper tubing means that the tube has a greater surface area, allowing the heat pump to exchange heat in a more efficient way. Additionally, variable speed fans are able to better cope with winter challenges.
Certified HVAC and Plumbing Service Throughout the Sacramento, CA Area
At Crystal Blue Plumbing, Heating & Air, we aim to be your trusted partner for heat pumps and ductless systems in Sacramento, CA! Since our establishment in 1976, we’ve provided high-quality services in Sacramento County. Initially focused on new construction, we evolved into a general contractor in 1981, working with vineyards, hospitals, and new homes. Expanding into a service company in 2007, we introduced HVAC services in 2012. From one truck, we’ve grown to five plumbing trucks and two HVAC vehicles. Our commitment is to deliver customer service reminiscent of the past.
Our services include HVAC repair, installation, and maintenance. We offer plumbing repair, tankless water heater installation, hydro-jetting, sewage repair, and video inspections. Contact Crystal Blue Plumbing, Heating & Air today and see for yourself why we are simply the best.