Joe Durkan, EEOS Programme Manager, SEAI
Plumbers and installers are the “go-to” guys in these situations. Whether it is emergency repairs, upgrades or a completely new installation, homeowners rely on their knowledge and expertise to advise them on the right approach. They represent the interface between the home owner and the wider world of energy efficiency. They have become, in a sense, energy ambassadors.
This is because, in order to ensure that the heating system is correctly specified, the plumber first needs to be able to accurately determine the actual heating demand of the home based on the details of the property and the needs of the occupant. This is where a great opportunity lies, because in order to calculate the heating load, the specifier needs to assess the building fabric, ventilation system and existing distribution system in the dwelling.
In the case of new or yet to be built dwellings, all of the information to determine this data should be readily to hand. Details of the construction, such as the levels of insulation, build type, ventilation systems etc, should all be known and these, in conjunction with the Building Energy Rating (BER) heat loss calculations, will help accurately determine what the heating requirement will be.
However, the majority of heating system installations are more likely to fall into replacements or upgrades. In these cases, especially when a BER isn’t readily available, the specifier has to determine the heating demand the old fashioned way. CIBSE’s Domestic Heating Design Guide (www. cibse.org/knowledge/knowledge-items/ detail?id=a0q20000008I7odAAC) is the key tool in these situations. The guide shows how to identify the principle heat loss areas in the dwelling, and how to calculate the relevant u-values, ventilation rates and distribution losses necessary to determine the heating requirements of each room and the overall hot water and space heating demand.
Minimising this overall heat demand is the key to an economical and efficient heating solution. Ultimately, the type of heat source is secondary to the more important considerations of ensuring that the heat demand can be met efficiently and economically, and that all elements are installed to the proper standards.
The information gleaned in the initial the homeowner could carry out, such as insulation or controls upgrades, that will reduce the overall heating demand. This is the opportune time to consider these works, and carrying them out in conjunction with the heating system upgrade will be more economical. The overall result will be greatly-improved levels of comfort and reduced heating bills (courtesy of the appropriately-sized heating system).
Almost certainly, the new heat supply (whether it’s a boiler, stove or heat pump) will require a lower rated heat output than the unit it is replacing. This is because the overall efficiency of heating appliances has improved dramatically over the last number of years. Therefore, it is vital that the installer accurately determines the heat load required to ensure that the replacement unit is correctly sized to operate at maximum efficiency.
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