Please see below for a list of definitions and terminology used to explain heat pump technology and aspects of the Clean Heat Rhode Island program.
Abode Energy Management (Abode): The Rhode Island Office of Energy Resources has contracted with Abode to administrate the Clean Heat Rhode Island program on their behalf.
AHRI: Equipment certification from the Air Conditioning, Heating & Refrigeration Institute (AHRI)
Air Source: A type of heat pump that extracts heat from the air and transfers it elsewhere to raise or lower the temperature of a space.
Air to Air: A variety of air source heat pump that collects heat from outside air, transfers it inside and distributes that heat through the air via a blower or fan.
Air to Water: A variety of air source heat pump in which an air-source outdoor unit is combined with an indoor system such as radiators or an air handler. It collects heat from external air and transfers to water to provide heat through a radiant heating system or ductwork.
Backup Heat: A heat source that operates as supplemental or emergency supply, typically pre-existing fossil fuel equipment.
British Thermal Unit (BTU): A unit of measurement that refers to the amount of heat necessary to raise the temperature of one pound of water by one degree Fahrenheit. BTU is used to measure the output of heat pumps and other HVAC systems. BTU capacity is typically measured by how much heat a heat pump can add or remove within one hour.
Capacity Drop: The loss of maximum heating capacity as outdoor temperatures drop. Typically, cold climate heat pumps are able to fully maintain their heating capacity down to 5 degrees Fahrenheit. Standard heat pumps may only maintain 60-70% of their total heating capacity at 5F.
Center for EcoTEchnology (CET): A sub-vendor for the Clean Heat Rhode Island program, providing services for commercial customers.
Coefficient of Performance (CoP): A ratio that expresses the output of a heating unit in relation to the input of energy. It is the rated capacity of the machine divided by its rated power input, though it can be expressed as a single figure or percentage. The higher the number, the more efficient.
Cold-Climate Heat Pump (ccASHP): Unlike standard air-source heat pumps, a cold-climate heat pump uses an inverter, or variable speed drive, that makes it capable of efficiently heating homes in cold climates.
Control Strategy: A Control strategy is needed when partially displacing fossil fuel heat to switch between the heat pump and backup heat. This could be managed manually by lowering the pre-existing system’s thermostat, shutting off a zone of heat, or done automatically with integrated controls.
Ducted Heat Pump: Also referred to as a central heat pump or a forced air system, it connects to ductwork inside and uses them to move warm or cool air throughout a building.
Ductless Heat Pump: Also referred to as a mini-split, it uses air handlers connected to an outdoor compressor unit to control the temperature of individual rooms.
Efficiency Rating: A ratio that measures the efficiency of a heat pump. Seasonal heating efficiency is measured by HSPF, while seasonal cooling efficiency is measured by SEER.
Electrical Service: The amount of amperage that your electrical panel can handle, or the amount of electricity your electric panel is able to distribute. A fully electrified home typically needs 200-amp electrical service.
Energy Star: A program run jointly by the U.S. Department of Energy and the U.S. Environmental Protection Agency to promote energy efficiency. The Energy Star logo is a symbol of certification for buildings and consumer products, such as appliances and heating systems, that meet certain standards of energy efficiency.
Greenhouse Gas (GHG): A gas that traps heat in Earth’s atmosphere. Carbon dioxide and methane are examples of greenhouse gasses.
Geothermal: Also referred to as ground source, water source, or earth-coupled, this is a type of heat pump system that exchanges thermal energy with the ground or a nearby water source and transfers it to air or water inside a building to heat or cool an indoor space.
Heating, Ventilation and Air Conditioning (HVAC): A broad term for the technology that provides environmental comfort inside buildings and vehicles. It can include heating, cooling, ventilation, air filtering, and humidity control.
Heat Pump: A temperature control system for buildings that transfers thermal energy from a cool space to a warm space via the refrigeration cycle. In cooling mode, it removes heat from an indoor space to make a building cooler, and in heating mode it transfers heat from outdoor sources such as air, ground, or water and moves it inside to make a building warmer.
Heating Seasonal Performance Factor (HSPF): A measurement of the heating efficiency of heat pumps expressed by the ratio of total seasonal heating output of the system compared to the amount of electricity it uses. The higher the HSPF rating of a unit, the more energy efficient it is.
Hybrid: Also called dual-fuel, they are configurations of heat pump systems that combine heat pump and fossil fuel heating systems. These designs are typically automatically controlled to switch between fossil fuel and heat pump systems based on an economic or capacity maintenance switchover temperature.
InClime: A sub-vendor for the Clean Heat Rhode Island program, providing incentive processing and reporting services.
Integrated Controls: The use of one system to control two separate heating systems. Integrated controls can be a single thermostat or multiple connected thermostats. Integrated controls are sometimes used when air-source heat pumps are used in conjunction with a backup heating system such as a fossil fuel boiler or furnace.
Kilowatt Hour (kWh): A unit that measures the amount of electricity used in an hour, equal to one kilowatt of power sustained for one hour, or 3,600 kilojoules.
Load Calculation: A calculation that determines the amount of BTUs necessary to provide adequate temperature control in a given space. Load calculations involve analyzing factors such as air volume of a space and the level of insulation.
Manual J: Process developed to accurately assess how much heating and cooling your home needs. Manual J results are compared to characteristics like static pressure, amount of air moved, and capacity to ensure the equipment chosen is sized correctly. There are two types, block load (entire home) and room by room.
Mini-Split: A type of ductless heat pump system in which an outdoor compressor unit is combined with multiple air handlers inside, usually one in every high-use room.
Office of Energy Resources (OER): A Rhode Island state agency whose mission is to lead the state toward a clean, affordable, reliable and equitable energy future. OER is the program administrator for the Clean Heat Rhode Island program.
Outdoor Unit: Also referred to as the compressor or condenser unit, it is the part of the heat pump system outside of the building that contains the compressor and the condenser coil.
Refrigerant: A fluid used in heat pumps and air conditioning systems that can change from a gas to a liquid state and back again repeatedly. There are many different types of refrigerant, which are classified in three broad categories according to how they absorb or extract heat.
Seasonal Energy Efficiency Ratio (SEER): A measurement of the cooling efficiency of heat pumps and air conditioners expressed by the ratio of total seasonal cooling output of the system compared to the amount of electricity it uses. The higher the SEER rating of a unit, the more energy efficient it is.
Single-Zone: Instead of one outdoor unit connected to multiple indoor air handlers, a single-zone heat pump is a single compressor connected to a single air handler.
Ton: The size, or capacity, of the heat pump is expressed in either tons or British Thermal Units (BTU). One ton of capacity is equivalent to 12,000 BTUs per hour or 3.5 kW.
Uniform Energy Factor (UEF): A standardized measure of how efficiently an appliance, such as a heat pump water heater, uses energy. Higher UEFs indicate more efficient systems.
Variable Speed Drive (VSD): A heat pump with a variable speed drive uses an inverter motor to increase energy efficiency by allowing for a full range of operation, similar to a vehicle accelerator, instead of a conventional unit that is either at 0% or 100% with no operation in between those values.
Weatherization: The process of making your home better protected from immoderate weather, which often involves sealing up air leaks and adding insulation in your home.
