Common questions about Environmental Heating Systems: These answers are based on my experience in the heat pump trade as a whole and are not aimed at promoting any one product or brand over another. Please feel free to e mail any other questions you may have and help keep this page relevant and up to date.
A : The COP or Coefficient of Performance is the measure of efficiency of a machine. Stated as a ratio of the power output to the power input. In the case of a heat pump it is the ratio of the Kw's of heat delivered by the heat pump to the Kw's of electricity consumed by the heat pump. A COP of 4:1 or 4 means for every 1Kw of electricity consumed by the heat pump 4Kw's of heat are delivered out of the heat pump.
A : The heat pump C.O.P. will vary depending on the source temperature (pipes in the ground or air) and the supply temperature (heating system). Both these temperatures must be stated with the C.O.P. The industry measure is 0/35 Celsius. When running the under floor 4.5 can be expected and 2.5 if heating the D.H.W. Therefore over the year an average of 4 should be achieved if the system is sized, designed and installed correctly. A C.O.P. above 5 is only found under factory conditions or with an air source heat pump on a damp August day.
A : A quality made heat pump on average 25 years. However this is dependent on the heat pump been installed correctly and having an efficient control. A good compressor in the heat pump would have a lifespan of 40'000 starts, it can then be seen that poor control allowing the heat pump to cycle on and off will wear the compressor out quicker. In 1988 the first year of my apprenticeship I was involved in the manufacture and installation of heat pumps which are still in use today in West Cork
A : A good heat pump will have a very low noise level and some are designed for inside use. However everyone will have a different perception of noise, if noise is an issue it is recommended that you arrange to listen to one running at night.
A : Domestic Hot Water or the fresh hot water you use in your sinks, baths and showers as opposed to the treated hot water circulating through your renewable energy heating system.
A : A heat pump can produce D.H.W. up to 65 Celsius if pushed, However to do so reduces the C.O.P. and can cause excessive ware on the compressor and is not advised. Special high temperature heat pumps can be found for specific needs. In general 40 to 45 Celsius is standard, this can then be increased by immersion during night rate electric tariff if needed.
A : A heat pump will run at its most efficient when used with under floor heating. The lower the heat pump flow temperature the higher the C.O.P. or the efficiency of the machine, as the under floor has a large mass to heat it will keep the heat pump at a low temperature usually 35 to 40 C. It is only with under floor heating that a heat pump will achieve a C.O.P. above 4.
A : No annual service contracts are required for a renewable heating system that has been correctly installed and commissioned. A heat pump has no serviceable parts and the compressor the only moving part is hermetically sealed. There is no oil, valves, filters or nozzles to clean or to change. Over the life time of the heat pump circulating pumps, pressure switches, thermostats or electronic starters may fail as with any heating or mechanical system and need replacement.