Table of Contents
Introduction
Ground source heat pumps are an energy-efficient way of heating and cooling a home or building. They use the free energy stored in the ground to provide warm, comfortable climate control for buildings while reducing energy costs. The process is based on natural heat exchange from the environment below ground into a geothermal system, producing warmth and hot water. This blog post provides an overview of how ground source heat pumps work and explores some of their benefits compared to traditional heating systems.
Image illustrating a ground source heat pump
Key Takeaways
- Ground source heat pumps are an energy efficient way of providing heating and cooling to a home or building, using the free energy stored in the ground.
- GSHPs typically use a loop system installed horizontally or vertically into the ground depending on land available, soil type and groundwater conditions.
- They offer up to 50% reduction in electricity consumption than other traditional HVAC systems while lowering carbon dioxide emissions .
- The efficiency ratings for ground source heat pumps can be expressed through Energy Efficiency Ratios (EER), Coefficient of Performance (COP) or Seasonal Performance Factors (SPF).
Loop Systems Of Ground Source Heat Pump
Ground source heat pumps (GSHPs) typically use a loop system to provide the necessary thermal energy.
Ground loops come in different configurations, each of which has its advantages and disadvantages depending on factors such as available land, type of soil, groundwater availability and other resources.
Horizontal Closed Loop System
It is usually the least expensive configuration of geothermal ground source heat pump installations due to requiring a relatively small amount of labour & equipment spent drilling down deep underground like it does with the verticcal loops.
This is also an ideal option for densely populated areas where there may not be space enough for large scale construction projects.
Vertical Closed Loop System
It involves vertically burying pipes instead of horizontally trenching along the earth surface so installers must drill down several feet ranging between one hundred and four hundred metres deep beneath Earth’s natural surface.
High Energy Efficiency Of Ground Source Heat Pump
Ground source heat pumps are recognized for their remarkably high energy efficiency. According to the US Department of Energy, ground-source systems require only 25% to 50% as much electricity compared to other heating and cooling units.
This means that ground source heat pumps can convert one unit of electricity into up to four times as much equivalent units of heat.
Moreover, since the beginning temperature already exceeds 80 degrees Fahrenheit (26.7 Celsius), these kinds of systems often operate at superior temperatures than electric resistance or oil fired furnaces do, leading to even greater cost savings and more efficient performance overall making them an optimal choice for eco-friendly homes looking for long-term savings without compromising on thermal comfort inside the space being heated/cooled.
Benefits Of Ground Source Heat Pumps
- Ground source heat pumps (GSHP’s) provide significant savings in energy costs and reduce environmental impact.
- They are much more efficient than traditional HVAC systems, as they use 25-50% less electricity to run.
- GSHP’s take advantage of the temperature difference between above-ground air temperatures and subsurface soil, drawing on thermal energy stored in the ground for heating or cooling air. This makes them a highly efficient system for both warm climates and colder temperatures where backup heating is often needed.
- Environmentally speaking, GSHPs require less electricity since most of the energy comes from renewable resources naturally present in the environment like solar radiation absorbed by rocks underground or moisture which releases it’s heat when heated by direct sunlight using ground source heat pumps produces less carbon dioxide emissions than other conventional methods that rely on burning fossil fuels.
- Additionally, due to their greater efficiency over traditional HVAC systems they also save homeowners money on utility bills while reducing demand on public power sources.
- Installation may involve some additional cost but if done correctly should result in lower maintenance expenses compared to comparable forced-air units running off gas or electric furnaces which represent 30%-70% higher operating costs per month according to Energy Star rated appliances making them a sound investment with long term returns.
How Does A Ground Source Heat Pump Work For Heating And Cooling?
Ground source heat pumps use a combination of natural ground temperature fluctuations and refrigerant cycles to absorb thermal energy from the ground, transport it inside a home or building, and provide heating and cooling.
Basic Operation Of A Ground Source Heat Pump
Ground source heat pumps use the thermal energy of the earth as a renewable energy resource to provide efficient heating and cooling for your home.
The system utilizes ground loops that are installed deep into the ground including either vertical or horizontal loops depending on available space, geology, and climate conditions.
The compressor of a ground source heat pump adds additional energy to this absorbed thermal energy before releasing it inside buildings where needed through radiators, floor coils/heating systems, fan coil units or individual HVAC systems used for distributing hot water or controlling temperatures.
Heat Absorption
Ground source heat pumps take advantage of the natural difference between the above-ground air temperature and subsurface soil to provide heating and cooling. They do this by using a ground loop system filled with water or refrigerants such as glycol to absorb thermal energy stored in the ground.
The fluid from the loop is pumped through a heat exchanger and also known as a ‘thermal exchange unit’ which then transfers that thermal energy into one side of an insulated pipe.
As it is driven round the loop, this hot liquid unevenly fills with more energy after each turn until it eventually reaches its capacity for absorption and releases back into the earth.
In many cases, different types of geothermal systems can be used depending on groundwater availability or geological characteristics such as horizontal or vertical piping designs commonly referred to as “ground loops”.
Heat transfer fluids are selected based on their ability to both efficiently conduct heat through well-insulated pipes while remaining corrosion resistant.
Refrigerant And Heat Transfer
Refrigerant is a special substance that facilitates heat transfer in ground source heat pumps, and it plays an essential role in how they function.
By flowing through the system, refrigerant absorbs energy from the loop underground and then releases it to the indoors when needed.
Refrigerants commonly used in these systems include hydrofluorocarbon (HFC), carbon dioxide (CO2), ammonia (NH3), or chlorine-free propane (R290).
Heat transfer is also key for a ground source heat pump system’s effective operation as it enables movement of thermal energy within components like liquid all the way down into the earth’s core where higher temperatures are found.
Heat absorbent pipes extend deep underneath several feet of soil or water acting as a thermal conductor with natural warmth from below conducted through them by means of circulating fluids.
Heat Rejection
Heat rejection is a crucial process in ground source heat pumps (GSHPs) and it helps maintain the system’s energy efficiency.
Heat from the interior of buildings or air-conditioned areas are extracted to the outside environment with the help of a compressor and heat transfer fluid, also known as refrigerant.
The compressed refrigerant at higher temperature moves into an outdoor evaporator coil, which removes heat from inside spaces when in cooling mode.
When GSHPs operate in heating mode they work by extracting thermal energy stored undergrond that can be used for warming indoors comfortably using water or antifreeze solution running through pipes providing more warmth than via air exchange founda typically found with indoor convector radiators or forced-air systems like furnaces.
Distribution Of Heat Or Cool Air
Distributing heat or cool air throughout a home is an important process in how ground source heat pumps operate.
As heat is absorbed from the ground and transferred to the heat pump, it needs to be distributed using a system of ducts and vents so that rooms will be at comfortable temperatures.
In winter, the circulation of warm air is achieved by using a refrigerant-filled loop inside the indoor unit. The refrigerant absorbs heat energy from the environment and circulates it around a sealed chamber which triggers compression heating when compressed molecules generate higher temperature before releasing into a distribution system as warmer air.
This type of systems uses two fans for suction and forced conveying simultaneously. One fan sucks low-temperature return air while another pushes out high-temperature supply air.
Role Of The Ground Loop System
The role of the ground loop system is essential for a ground source heat pump to function correctly. The ground loop contains piping laid under or near the surface that stores and absorbs heat from underground, eventually transferring it into an interior space as needed.
These pipes are filled with a refrigerant-water mixture, which can range in temperature depending on the type of earth below them. The two main types of loops used are closed loops and open loops.
Closed loops typically utilizes vertical or horizontal trenches dug into the soil either adjacent to where the equipment is located or at some other location within close proximity such as a well field, while open loops can be gravity fed directly from nearby lakes, reservoirs, streams or oceans.
The application of properly designed and constructed geothermal cooling and heating systems in residential settings can save homeowners up to 30 percent on their combined electric bills compared with conventional electric HVAC systems since they rely mainly on stored thermal energy in order to maintain comfortable indoor temperatures without relying solely on supplementary electricity consumption.
Explanation Of Compressor And Refrigerant
The compressor and refrigerant are key components of a ground source heat pump system that work together to transfer thermal energy from the earth’s surface.
The compressor is an electrically driven device which serves to compress the gaseous refrigerant, powering it through pipes so that heat can be transferred between locations where required.
This makes the ground source heat pump efficient by decreasing its running costs, as the same amount of power can be used to move colder or warmer air at different levels of efficiency than would otherwise have been necessary.
Meanwhile, the refrigerant used plays an important role in transferring this stored thermal energy away from warm spaces for use in cooling or towards cooler areas for use in heating.
It functions best when operating within specific parameters. If conditions fall outside these limits then costly damage can occur due to performance being compromised.
Refrigerants such as R410A have better performance compared with other traditional substances like Freon due largely having zero ozone depletion characteristics while still providing optimal functioning even under extreme climate conditions.
Factors Affecting The Efficiency Of Ground Source Heat Pumps
Efficiency of ground source heat pumps depends on factors including the
- quality of the ground loop system,
- size of the system
Quality of the ground loop system
Ground source heat pumps (GHPs) are highly dependent on the geological factors of an area, such as the soil type and thermal properties including thermal conductivity and diffusivity.
This means that in order to effectively install a GHP system, it is important to consider how these variables may affect efficiency.
Thermal factors like subsurface temperature, moisture content, rocks, or soil type greatly impact a GSHP’s overall efficiency. In areas with thick unsaturated zones or limestone under higher ground surface temperatures around 8°C/47F there may be less efficient performance due to reduced heat flux from shallow aquifers.
Also when selecting a system size look into variable speed compressors for increased efficiency instead of traditional single-speed compressors since they have more power and develop greater operating efficiencies over time without consuming extra power resources.
System Size And Efficiency
The size and performance efficiency of a ground source heat pump is key to its effectiveness. A correctly sized system ensures the installation meets both the heating and cooling requirements of a particular building or residence.
Additionally, it is imperative to use proper calculations when selecting components to ensure enough power is generated for all home needs, while also ensuring that fuel consumption remains efficient.
For optimal results, an efficient heat transfer between thermal sources must be established which references factors such as the thermic condition of the groundwater used in injection-extraction based systems.
It is important to remember that geothermal loops conductors are not capable of producing energy from thin air but rather draw from existing energy present within our environment. This process has limits as related to material thermal resistance placed between extraction points (earth) and point of application (home).
Ground Source Heat Pumps In Cold Climates
To operate in cold climates, ground source heat pumps have specialized features such as winterized refrigerant and a series of extra-deep loops to prevent freezing.
Winter Operation
Ground source heat pumps are capable of providing efficient heating for residential and commercial properties, even in some cold climates.
To understand their winter operation, it is important to firstly acknowledge the advantages they offer over traditional, air-source heat pump systems
.
Rather than relying on fluctuating air temperatures for its energy source, a ground-source system taps into the consistent underground temperatures that remain largely unchanged during winter months (as opposed to above ground which can drop significantly).
However, since most areas experience a range of climate conditions throughout the year (including cold winters) there may be periods when surface temperature drops drastically resulting in lower efficiency as low as 20%.
This is due to he fact that the average input temperature from the ground loop will also decrease causing strain on both interior units and compressors used by this type of system.
In order to fully maximize efficiency during times of extreme temperatures homeowners should consider topping up any existing loop fields with insulation pellets which will help ensure optimal performance.
Additionally manifold boxes should also properly covered or insulated year round since keeping them exposed to outdoor elements all year long might somehow reduce function capabilities and bring about service issues if not taken care off periodically through seasonal maintenance procedures.
Snow Removal
Snow buildup can have a significant impact on the function and efficiency of ground source heat pumps in cold climates. The snow and ice that accumulates around the buried ground loops may interfere with the exchange of thermal energy between the loop system and the indoor environment, thereby reducing their ability to deliver heating or cooling as needed.
Additionally, snow accumulation can cause an increase in pressure which could potentially damage the system’s components.
When it comes to maintaining a geothermal unit’s performance during wintertime, professional maintenance is especially important for areas prone to heavy snowfall or temperatures below freezing point.
A certified technician will be able to check for potential problems resulting from Snow mold that condenses due to inadequate air circulation traps and moisture buildups caused by deteriorating insulation materials surrounding your pipes .
They will also inspect whether there are any blockages or restrictions within pipes leading up towards house causing reduced flow rates in order prevent warm water supply failures when needed most during colder days.
Protection Against Freezing
Ground source heat pumps are designed to function in a relatively wide range of environments including colder climates where temperatures can reach below freezing.
In order for these systems to endure cold winter weather without interrupting service, it is essential that the ground loop system be properly protected from succumbing to low temperatures.
The antifreeze solution circulating through the closed-loop geothermal system allows it to continue operating seamlessly during winter months due to its higher boiling point than water and larger resistance against solidification.
This also eliminates the need for excessive amounts of energy produced by backup heating systems when outdoor temperatures drop especially critically low or even bordering subzero conditions at times.
It’s worth noting however, that exposure over extremely long periods may lead to some gradual increase in concentrations within sections of the pipe which necessitates careful assessment followed up by appropriate topping up before reinstating operation once again if needed each season.
Comparison With Other Heating Systems
Ground source heat pumps offer greater energy efficiency than other heating systems like gas-powered boilers, reducing utility bills and making them a more cost-effective option.
Efficiency Comparison
Ground source heat pumps (GSHPs) and air source heat pumps (ASHPs) are compared in terms of efficiency to provide a better understanding of each system’s performance.
The efficiency of these systems can be evaluated using the coefficient of performance (COP), which measures the amount of energy output per unit of energy input. Higher COP values indicate a greater efficiency for the heat pump system.
| Efficiency Comparison | Ground Source Heat Pumps (GSHPs) | Air Source Heat Pumps (ASHPs) |
|---|---|---|
| Coefficient of Performance (COP) | 3-5 | 2-3 |
| Energy Efficiency | Produces around 10,000 BTUs with 1 kWh of electricity | Produces around 7,000 BTUs with 1 kWh of electricity |
| Bill Savings | Can save up to 20% of billing costs compared to other heating systems | Can save up to 10% of billing costs compared to other heating systems |
| Impact of Temperature | Less affected by outdoor temperature changes due to the stable temperature of the ground | Impacted by outdoor temperature changes; efficiency decreases in extreme weather conditions |
| Heating and Cooling Efficiency | Can heat a house three times more efficiently when paired with a heat pump water heater | Can heat a house two times more efficiently when paired with a heat pump water heater |
Factors that affect the COP of a heat pump system include the system’s design, installation, and maintenance, as well as the specific ground conditions and geology of the installation site.
To optimize the COP and achieve maximum efficiency, it is crucial to ensure proper sizing, installation, and maintenance of the heat pump system. Additionally, selecting the most suitable type of ground loop system based on the site’s specific conditions can further enhance the efficiency of a ground source heat pump.
Cost Comparison
When comparing the costs of ground source heat pumps with other heating systems, it is essential to consider not only the initial investment but also the ongoing operating expenses. The table below summarizes the capital costs, operating costs, and overall efficiency of ground source heat pumps (GSHPs) and air source heat pumps (ASHPs), as well as traditional heating systems, providing a comprehensive overview of the financial implications for homeowners and professionals alike.
| Heating System | Capital Cost | Operating Cost | Efficiency |
|---|---|---|---|
| Ground Source Heat Pump (GSHP) | $15,000 – $45,000 | $107/year (heating mode) | 300-600% (COP) |
| Air Source Heat Pump (ASHP) | $4,000 – $8,000 | $225/year (heating mode) | 200-300% (COP) |
| Gas Furnace | $3,000 – $6,000 | $700 – $1,000/year | 80-95% (AFUE) |
| Oil Furnace | $5,000 – $8,000 | $1,000 – $1,500/year | 80-90% (AFUE) |
| Electric Baseboard Heater | $150 – $200 per heater | $900 – $2,500/year | 95-100% (AFUE) |
It is important to note that while the initial capital cost for a ground source heat pump is higher than most other heating systems, the long-term savings from reduced operating costs can offset this investment.
Additionally, ground source heat pumps provide exceptional energy efficiency, making them a sustainable and environmentally friendly choice for both heating and cooling purposes.
Environmental Comparison
Ground source heat pumps have significant environmental advantages compared to traditional fossil fuel-based heating and cooling systems.
These benefits include a reduction in carbon dioxide emissions, lower energy consumption, and a decreased reliance on non-renewable energy sources. The table below illustrates the difference in environmental impact between ground source heat pumps (GSHPs) and conventional heating and cooling technologies.
| Factors | Ground Source Heat Pumps | Traditional Fossil Fuel-Based Heating and Cooling |
|---|---|---|
| Carbon Dioxide Emissions | Geothermal heating and cooling produce 75% to 85% less carbon dioxide emissions than gas and oil-based systems. | Traditional gas and oil heating and cooling systems produce higher amounts of carbon dioxide emissions, contributing to climate change. |
| Energy Consumption | GSHPs are more energy-efficient than air source heat pumps, resulting in reduced energy consumption and lower utility bills. | Conventional heating and cooling systems have higher energy consumption, leading to increased utility costs and a larger carbon footprint. |
| Non-Renewable Energy Sources | GSHP systems utilize renewable energy from the earth, reducing dependence on non-renewable resources such as oil and gas. | Fossil fuel-based heating and cooling systems rely on non-renewable resources, which can have negative consequences on the environment and contribute to energy scarcity. |
As evidenced by the table, ground source heat pumps offer a more environmentally friendly alternative to conventional heating and cooling systems.
Cost And Installation Guide For Homeowners
Homeowners should carefully consider the cost, supervision of installation process, and necessary permits and regulations before installing a ground source heat pump system.
Cost Of A Ground Source Heat Pump System
Installing a ground source heat pump system can be expensive, ranging from $10,000 to $40,000 when factoring in size of the home and type of loop system used.
A typical geothermal heat pump installation costs around $12,708 to install with a range between $2199 and $21 480 depending on your specific needs and requirements.
Despite the higher initial cost investment in this kind of energy-efficient system can save homeowners plenty off their utility bills in the long run due its high efficiency rate compared to traditional heating systems.
Furthermore introducing some convenience into maintenance as these units require less frequent service visits since there are lesser moving parts than other traditional equipment like furnaces or split HVAC systems.
It has lower noise levels too since all components including fans motors ,pumps etc., are inside which need not make more sound thus making it more preferred over others despite initial rates being slightly higher comparatively.
This makes Geothermal Heat pumps an ideal choice ensuring lower operating costs yet best performance at peak temperatures alongside keeping environment clean and greenerby using renewable sources instead of burning classic fuel resources such fossil fuels.
Steps Of Installation
Installing a ground source heat pump involves four main steps which include ground loop installation, ductwork installation (if necessary), heat pump installation, and system testing.
Ground loop installation is an important step of the process as it ensures the effective and efficient transfer of thermal energy between the earth and the heat pump. Here are the different types of loops that can be used in ground source heat pump systems and their respective steps for installation.
• Closed Loop System:
This type of system requires two pipes to be buried at least 6 feet below the ground surface.
The first pipe is filled with a mixture of antifreeze and water, while the other contains only water – both will circulate throughout this closed-loop system carrying air through from the surface.
The installation of this system should start with trenches being dug around your property for each pipe’s separate loops, ensuring that enough vertical gap has been achieved between them before backfilling starts.
After that, each pipe needs to be connected to a heat exchanger on the building’s side whereby they will interact with one another, and finally, these pipes should make contact with air thermostats for responding whenever heating or cooling tasks need to be carried out by your ground source heat pump system.
• Horizontal Slinky Loops:
This method makes use of long plastic or rubber hoses arranged into circles that are laid flat across your garden in shallow trenches.
When taking this approach, one single loop needs to be put in place instead of two closed-loop pairs. It is preferable to use slinky loops around houses comprised on large gardens since it reduces costs due its overall lower material requirements compared to more complex systems like vertical drilling.
To install a horizontal slinky loop system you would need three trenches so that all pipes fit neatly within them after which they must also be connected to a single lengthwise piece looping back onto itself thereby forming a connected circle, once again, an air thermostat should also be hooked up on either ends for proper regulating purposes.
• Vertical Drilling System:
If you happen to possess smaller plots without much space, then you could opt for installing vertical drill loops as they only require shafts being sunk deep down into the soil accompanied by pipes which take connection with almost any attribute going through sealing top plates back above surface.
Permits And Regulations
Before deciding to install a ground source heat pump (GSHP) system, it is important to understand the permits and regulations associated with installation and operation of GSHPs.
These are typically regulated by state or local governments depending on location.
In Massachusetts for example, the Department of Environmental Protection regulates installations of both water supply wells and return wells used as part of GSHP systems which require a well construction permit from local health departments.
Similarly, the Pennsylvania GSHP Manual recommends best management practices related to environmental issues regarding geothermal heat pumps in that state while Bowman Mechanical Services provides an overall guide to geothermal heat pump installation across various states.
This is an important step in understanding efficient energy-saving solutions, so take time to do research before taking action .
Maintenance Guide For Homeowners
Proper maintenance of ground source heat pumps is essential to ensure optimal operation and efficiency of the system.
Importance Of Regular Maintenance
- Regular maintenance for ground source heat pump systems is essential to keep the system in optimal working condition. Without routine inspection, repair and replacement of crucial components, the system’s performance could suffer and its lifespan will be shortened.
- Homeowners can ensure their heat pump’s long-term performance by performing preventive self-maintenance tasks such as cleaning the air filter, checking refrigerant levels, inspecting ductwork for any signs of wear or damage, and examining outdoor coils.
- If large amounts of debris are found clogging up an outdoor coil during an inspection proper cleaning should take place immediately in order to improve energy savings because a dirty condenser decreases its heating capacity over time leading to higher energy bills.
- homeowners should have yearly professional inspections performed to make sure that all parts are running efficiently before any potential problems arise.
DIY Maintenance Tips
It is important to regularly maintain your ground source heat pump system in order to get the best performance out of the unit. Homeowners can easily perform some minor routine checks and tasks on their own to ensure that their unit continues running optimally.
Here are some DIY maintenance tips for ground source heat pump systems:
- Clean or replace all filters according to manufacturer’s instructions;
- Check all outdoor coils and intake passages for dirt/debris build – up every spring;
- Clear obstructions from condensate drains at least once a year;
- Monitor sound levels with decibel meter annually, usually between 45 – 50 dB on low speed setting;
- Inspect all wiring connections regularly each month;
- Regularly check ducts for any damage caused by pests or other sources of damage such as water intrusion.
- Measure differential pressure across filter/outside coil every 3 months & adjust blower speed accordingly.
- Always use appropriate protection when carrying out any work on the system including turning off power supply prior to servicing components like fans, compressors etc.
- Have an HVAC contractor inspect hot surface igniters annually during fall season and spray frame contact surfaces with silicone lubricant if required.
- Always report any operating issues encountered while using the system immediately so that qualified technicians can carry out repairs quickly and accurately whenever possible before further damages occur.
Professional Maintenance Options
- Professional technicians are trained to identify potential problems early on, preventing them from becoming serious and expensive to fix.
- Professional maintenance includes tests on the performance and efficiency levels of GSHPs to ensure energy efficiency.
- Testing refrigerant pressure levels is an important maintenance task to optimize heat transfer and overall system performance.
- Regular examination of air flow across the evaporator coil is necessary to ensure efficient cooling and temperature control.
- Cleaning condenser coils by professionals reduces wear and tear, improves efficiency, and extends the useful life span of GSHPs.
- Monitoring electrical connections within the unit is crucial to prevent functionality issues and potential damages.
- Professional servicing helps minimize the risk of unexpected breakdowns and costly repair bills.
- Neglecting preventative maintenance can lead to decreased system performance and potentially higher repair costs.
- The cost of regular professional maintenance is worthwhile compared to the potential consequences of inadequate servicing.
- Professional maintenance options offer peace of mind and ensure that GSHPs operate smoothly and effectively.
FAQs:
1. How does a ground source heat pump work?
A ground source heat pump (GSHP) works by harnessing the stored thermal energy in underground deposits to provide heating and cooling solutions for properties. It passes water through an exchange loop buried in the ground, where it takes on either low-grade warmth or coolness depending on its use/seasonal requirements. The system then circulates this water through internal systems such as radiators, underfloor heating etc which warms the building or creates cooling air currents to be used in summer months.
2. What are the benefits of using a GSHP?
Ground source heat pumps offer significant cost savings compared to traditional systems due to increased efficiency ratings – often saving up to 50% less money than fossil fuels – and they’re generally considered more environmentally friendly solutions than gas boilers or electric powered heats pump due too their low reliance on non-renewable sources of energy and thermal powers from nature itself! Additionally they tend to have very long lifespans with minimal need for maintenance & repairs over time; typically lasting about 20 years before needing replacing!
Conclusion
Understanding the efficiency ratings of ground source heat pumps is essential for homeowners deciding to invest in one. Higher efficiency ratings typically result in lower operational costs, improved comfort and greater energy savings over the lifetime of the system. Efficiency ratings for ground source heat pumps are often expressed as Energy Efficiency Ratios (EER), Coefficient of Performance (COP) or Seasonal Performance Factors (SPF). Knowing which terms correspond with a particular model can help you determine its overall effectiveness. Residential heat pump units usually range from an EER rating of 13 to 20 or higher, with SPF values ranging from 1.2-6.0 depending on your climate zone and size/type of system you have installed. Consumers should also look for Heat Pump Certification Labels issued by commercial agencies such as AHRI, which indicate adherence to industry standards and quality assurance levels regarding sound levels, safety codes and maximum energy efficiency performance tests among other parameters.
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