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Sizing a Heat Pump Correctly Directly Affects Your Home's Comfort and Humidity Control

Heat pumps are less well-known than traditional air conditioning and heating systems, but they offer an attractive alternative for customers who want to save energy and money. They offer an efficient option for both cooling and heating, and all in one system. Keep reading to learn more about how heat pumps work, sizing a heat pump, and whether a heat pump is the right choice for your home.

What is a Heat Pump?

Unlike conventional furnaces, but not dissimilar to A/Cs, heat pumps work by transferring heat rather than generating it. In the summer, heat pumps move heat from inside your house to the outdoors, and in the winter they "pump" heat from the outdoors into your home. They employ the principle of refrigeration to accomplish this. In the summer, heat pumps can make your home more comfortable by reducing humidity levels as well as by lowering the temperature. Some heat pumps also have a "dehumidifying" or "dry" mode which alternates between heating and cooling in order to reduce humidity while maintaining a constant temperature. Many heat pumps also have a "fan-only" feature that provides ventilation in your home when the weather's mild enough to go without the cooling function on.

How Does a Heat Pump Work?

When the heat pump is in cooling mode, the outside compressor pushes refrigerant through the indoor evaporator coils where it captures heat from the air inside your house. The compressor then pumps the coolant outdoors where it's compressed into a liquid and in the condensing coil, releases the heat that it has captured. The refrigerant then returns indoors to capture more heat. In the winter, the flow of refrigerant is reversed so that the heat pump captures heat outdoors and releases it inside your home, increasing the temperature. Depending on the type of heat pump you have, it can capture heat from the air, the ground, or a nearby body of water. Heat pumps that use heat from the ground or from a body of water are called geothermal heat pumps. While these are the most efficient type of heat pump, the most common is the air-source heat pump.

Sizing a Heat Pump

Correctly sizing a heat pump is important to ensure the appliance operates at maximum efficiency. Heat pumps are far from one-size-fits-all devices. A heat pump that's too small will struggle to heat and cool your home during extreme temperatures, and will be more likely to freeze in cold weather. A heat pump that's too large will cycle on and off frequently, wasting energy and providing uneven conditioning. At the same time, the frequent on-and-off modes will prevent an over-sized heat pump from providing adequate humidity control or air filtration. It is also more expensive to buy a larger heat pump, so an over-sized heat pump does not make sense financially.

Calculators are available online that will help you develop a rough estimate of what size heat pump you need, but it's far better to consult a licensed home comfort professional before sizing a heat pump. A qualified HVAC professional will perform a Manual J load calculation on your home, inputting the size and layout of your home along with a variety of other factors. Once equipped with the results, the professional will recommend the right size heat pump system for your home, as well as suggest ways to lower its heating and cooling loads.

Heat Pump Benefits

Heat pumps offer many benefits over conventional furnaces and air conditioners. For cooling, air-source heat pumps rival high-efficiency air conditioners in terms of energy savings and performance. In heating mode, heat pumps can provide three times the heat energy of the electricity that's powering them. This amounts to 300 percent efficiency, as compared to the 98 percent efficiency of a top-of-the-line gas furnace. When heating in cold-winter climates such as Chicago, however, during extended cold periods, air-source heat pumps may have difficulty extracting heat from the cold outside air. When this happens, they will fall back on emergency heating, either with backup electric resistance coils or a gas furnace. If you have a furnace for emergency heating, this provides a potentially inexpensive backup option when gas prices are low, as they are now.

Heat pumps can also can be quieter than traditional air conditioning and furnace systems, which can be noisy. Many modern heat pumps incorporate a washable air filter that can improve the air quality in your home. These filters remove dust and allergens from the air, making family members with asthma or allergies feel more comfortable. Some air filters even come with a deodorizing feature to minimize unpleasant household odors. Any air filters will need to be washed or replaced regularly in order to be effective.

At Comfort24-7.com, we are qualified professionals serving Chicago, Northwest Indiana and Southwest Michigan. We provide emergency 24-7 HVAC service and can help you solve your home comfort problems. Contact us today for information about heat pump sizing or maintenance.

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