Glossary of Terms
Coefficient of Performance (COP) of a heat pump is a ratio of output heat energy delivered by the unit to the input electrical energy consumed by the unit.
Cylinder Stat
A Cylinder Thermostat monitors the temperature of the domestic hot water. It switches the heat supply from the boiler to the hot-water cylinder on and off. It works by sensing the temperature of the water inside the cylinder, switching on the water heating when the temperature falls below the thermostat setting, and switching it off once the setting has been reached.
Dwelling Energy Assessment Procedure (DEAP) is the official Irish procedure for calculating and assessing the energy performance of a building.
DHW – Domestic Hot Water
Fines
The dust to be found in a bag of pellets (from the fine particles caused by the break-up of the pellets). Fines should be less than 1%.
Flux
The rate of heat transfer. For geothermal heat pumping systems, it is the measurement of the flow of heat, which moves from hot to cold.
Heat Loss
Heat loss is measured in watts per square meter per degree. This is also known as the U-Value
Insulation
“Insulation” reduces the rate of transfer of heat energy from the inside of the house to the outside.
Kilowatt-hour (kWh) is the measure of energy equal to the use of one kilowatt (kW) in one hour
Motorised Valve
A Motorised Valve is used to control water flow from the boiler to the heating and hot water circuits and is operated electrically. Motorised Valves are used with fully pumped systems.
Primary Energy is the delivered energy plus an allowance for “overheads” incurred in extracting, processing and transporting a fuel or other energy carrier to the dwelling. Primary Energy consumption determines the Building Energy Rating.
Technical Guidance Document’s (TGD) are published by the Department of the Environment and Local Government and provide guidance on compliance with building regulations.
Thermal bridging
The process of losing heat through uninsulated joints such as where walls meet walls, floors meet walls, ceilings meet walls, and where insulation is not snug enough to fill such joints. Thermal bridging occurs through studs and fixings – even through the fixings used to install the insulation material itself. Windows and doors are also key potential locations for thermal bridging
Thermostatic Radiator Valves (TRVs) sense the air temperature around them and regulate the flow of the water through the radiator. They help improve comfort in your home by allowing you to set different temperatures in different rooms.
U-Value is the measure of heat loss or gain in watts per m² of area due to the differences between inside and outside air temperature. It is measured in W/m²K. The lower the figure the better.