Hybrid Heating Systems FAQs

The VortexAir Hybrid is a combination of a high efficiency condensing oil boiler and an air source heat pump, interconnected using a control system, such that they operate together as a single unit. It is intended to be installed where a heat pump along may not be suitable for a particular application.

The control system on the hybrid unit monitors the ambient (outside) air temperature and allows only the heat pump to operate when the air temperature is high enough for it to meet the heat demand of the building on its own. At lower ambient air temperatures the boiler will operate alongside the heat pump, providing a boost to the flow temperature. When the ambient air temperature falls lower still, the boiler is operated at its full output at a higher flow temperature to enable the hybrid unit to meet the higher heating demand of the building.

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A hybrid unit enables the optimum use of both an inverter driven air source heat pump and a highly efficient condensing oil boiler, throughout the year, as the ambient air temperature (and consequently the heat demand of the building) changes, thus providing the most efficient use of both the renewable and non-renewable energy sources. The VortexAir Hybrid allows end-users to benefit from low carbon heating for the majority of the year with the boiler used as a back up during colder periods.

Heating system radiators in existing properties are usually sized using the higher water flow temperatures produced from a boiler and so, to meet the same heat demand using the lower flow temperatures produced by a heat pump, the radiators would normally need to be increased in size. Using a hybrid unit combines the higher flow temperatures produced by a boiler, with the efficient operation of a heat pump, to meet the buildings heat demand throughout the year.

When the weather is warmer, i.e. in the spring and autumn, the heat pump works independently and the existing radiators can meet the heat demand with the lower flow temperature. This allows the very efficient use of electrical energy to drive the heat pump for large periods of the heating season. When the weather gets colder, the boiler operates to provide the additional energy required negating the need to increase radiator sizes.

The boiler is always fitted first and the heating system in the building is connected directly to it, whether or not it is located outside next to the heat pump or indoors. The heat pump is then installed and also connected directly to the boiler.

The VortexAir is designed to be installed outdoors, i.e. both the boiler and heat pump are located next to each other outside the building. However, it is also possible for the boiler to be installed internally with the heat pump still outside. Full details for both types of installation are given in the installation instructions supplied with the unit.

No. The boiler can be installed and, if necessary, operated as a stand-alone unit for an indefinite period until the heat pump can be installed and connected to it. This is particularly useful when an existing boiler has to be replaced in an emergency due to a breakdown. The installation of the heat pump can follow at a later date when convenient.

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The VortexAir Hybrid uses the Grant low level balanced flue system (or Yellow system) irrespective of whether the boiler part is located inside or outside the building. In the case of it being located indoors, the flue system exits at the rear of the unit and passes through the external wall of the building. If the boiler is outside it is fitted through the right hand side of the unit, above the boiler access door. The hybrid unit must be located such that the flue terminal clearance requirements of BS5410-1:2014 are complied with.

As with Grant Vortex boilers, the VortexAir Hybrid is only suitable for use with standard kerosene (Class C2 to BS2869). Gas oil (Class D to BS2869) must not be used with the hybrid boiler.

No. As not all installations will require a heat meter and electricity meter, the Grant VortexAir Hybrid is supplied without any meters fitted. However, in accordance with MCS metering requirements, the Grant VortexAir Hybrid is supplied ‘meter ready’ to allow both the heat meter and electricity meter to be easily fitted if required. The heat meter and electricity meter are available as accessories from Grant.

Installation of the hybrid unit requires an installer who is both competent in the installation of oil fired boilers (preferably a registered oil installer, e.g. OFTEC registered or similar) and also able to install an air source heat pump. Grant strongly recommends that any installer intending to fit a VortexAir Hybrid should first attend a Grant training course.

Usually, compliance with the Town and Country Planning legislation for England, and the MCS Planning Standards, for permitted development means that Planning Permission is not usually required to install a Grant VortexAir Hybrid. However, this should be checked with the Local Authority Planning Department in all cases. It is the responsibility of the householder to undertake this check.

This is a complicated question to answer. Any cost benefit is dependent on a variety of different factors, including the heat demand of the property, the type of heating system currently installed, the pattern of heating usage, the cost of both electricity and heating oil at the time of installation. Consequently, cost benefits will vary from one installation to another.