Your Guide to Heating Jargon
The world of heating and cooling is full of technical terms and acronyms. We’ve created this glossary to provide simple, clear explanations for homeowners. Click on any term below to see its definition.
Glossary Terms
A buffer tank is essentially a large, insulated container of water that acts as a “heat battery” for your heating system. It stores hot water produced by your heat source (like a heat pump or boiler) and holds it until it’s needed for space heating. This allows your heat source to run in longer, more efficient cycles instead of constantly turning on and off. It’s a very common type of Heat Accumulator.
COP is a simple efficiency rating for a heat pump. It measures how much heat energy the pump produces for every unit of electrical energy it consumes.
Example: A COP of 3 means the heat pump generates 3 units of heat for every 1 unit of electricity it uses.
In short, a higher COP is better as it means you’re getting more heat for your money.
“Delta-T” is just a technical way of saying “temperature difference.” In a heating system, it specifically refers to the temperature difference between the hot water leaving a device (like a heat pump) and the cooler water returning to it.
Maintaining an optimal Delta-T is crucial for efficiency. If the difference is too small, it means the system isn’t giving off its heat effectively, which can cause your heat pump to work inefficiently.
DHW is the acronym for “Domestic Hot Water.” It’s simply the hot water you use from your taps for things like showers, washing dishes, and laundry. It is separate from the water that circulates within your space heating system (like in your radiators or underfloor pipes).
A heat accumulator is anything that can store thermal energy—think of it as a “heat battery.” This can be a dedicated device like a Buffer Tank, or it can be the physical mass of your house itself (concrete floors, brick walls) if you have a system like underfloor or wall heating that heats them directly.
A hybrid heating system is one that intelligently combines two or more different heat sources to provide heat in the most efficient and resilient way possible.
Example: A system that uses an electric heat pump as its main source, but can also use solar thermal collectors on sunny days or a backup fuel boiler during extreme cold spells. The OptiHeatX approach focuses on seamlessly integrating these sources into a single, smart system.
A monoblock heat pump is a type of air-to-water heat pump where all the major components (compressor, heat exchanger, etc.) are contained within a single, self-contained unit that is placed outdoors. This design simplifies installation as it doesn’t require a certified technician to handle refrigerant lines between indoor and outdoor units, making it ideal for DIY projects.
A split system heat pump consists of two separate units: an outdoor unit (which contains the compressor and condenser) and an indoor unit (the air handler or evaporator). The two are connected by refrigerant lines that must be installed by a certified professional.
Thermal inertia is a property of a material or building that describes its resistance to changes in temperature. A building with high thermal inertia (typically one with high thermal mass) will heat up and cool down very slowly. This helps maintain a stable, comfortable indoor temperature with fewer fluctuations.
Thermal mass refers to the ability of a material to absorb, store, and release heat. Dense materials like concrete, brick, and stone have high thermal mass. In a home, these materials can act like a “heat battery,” absorbing heat when the heating system is on (or from the sun) and slowly releasing it later. This is a key component of a high thermal inertia building.
An on-grid (or grid-tied) solar power system is connected to the public electricity grid. It allows you to use the solar power you generate, and if you produce more than you need, you can often send the excess power back to the grid (sometimes for credit). When you need more power than your panels are producing, you automatically draw it from the grid.
An off-grid solar power system is completely independent of the public electricity grid. It requires a battery bank to store the solar energy generated during the day so that you have power available at night or on cloudy days. These systems provide true energy independence but are typically more complex and expensive due to the need for batteries and charge controllers.