Which off-gas heating option to choose?

Which off-gas heating option to choose?
The Grant VortexBlue oil boiler incorporates the latest clean burning technology

Both oil and renewables can offer efficient, reliable heating for those rural properties without access to mains gas.

For housebuilders and developers in off-gas areas, choosing the right heating system is an important part of any new build or renovation. Whether opting for a traditional oil-fired boiler, a greener alternative like heat pump or biomass boiler, or perhaps a combination of both, there is an efficient solution for practically any property. Depending on your resale market, potential clients may see renewables, such as heat pumps or solar thermal, as adding value to their home. Alternatively, they may be more confident with a fuel source they are familiar with and feel an oil-fired condensing boiler is a cost effective, dependable choice.

Oil fired boilers

Modern oil-fired boilers are no longer the inefficient machines of the past: new condensing appliances can operate at almost half the cost of a typical 25 to 30 year old boiler and are easy to install and maintain.

For over two years both Grant and Riello’s R&D teams worked on a joint initiative to develop a compact Blue Flame burner and match this to Grant’s Vortex condensing oil boiler range. The principle of combustion on blue flame appliances, such as the Grant VortexBlue, differs from that of a yellow flame burner in that the combustion gasses are re-circulated through a specially designed blast tube, allowing them to mix with atomised droplets of fuel and fresh air (oxygen) drawn in through the burner, to produce a clean blue flame with far lower NOx emissions. Guarantees also bring peace of mind for the homeowner and we are currently offering a 10 year guarantee via our G-One Accredited Installer network, which is five times longer than standard Grant boiler guarantees.

In September this year, Grant also introduced new Vortex boiler house models, increasing the number of heating outputs on offer. A boiler house appliance is ideal for locations which are difficult to access, where a white cased version is not the most appropriate solution. The range recently welcomed new red cased models to cater for properties that need smaller boilers. New sizes include 15/21kW, 21/26kW, 26/35kW, 36/46kW, 46/58kW and 58/70kW outputs.

Air source heat pumps

Compared with other domestic heating methods, heat pumps can provide annual savings on fuel bills. Units like the Grant Aerona3 can deliver over three times the amount of energy for every 1kW of electricity used depending on the flow temperature and the climate conditions prevailing at the time.

Incredibly efficient, the Grant Aerona³ heat pump is available in three outputs of 6kW, 10kW and 16kW, all ERP rated A++ and MCS Approved. The Heat Pumps are ‘inverter driven’ producing a consistent heat output and in addition, they are compact in physical size. By a combination of clever design features and improved insulation, the Aerona³ achieves low noise levels whilst operating.

Heat pumps will suit properties that want to incorporate a green technology when space is at a premium. As with all Grant products, our heat pumps are geared towards easy installation and maintenance for both the housebuilder and end user. This is because there is typically less annual maintenance, lower carbon emissions and, when correctly sized and installed, reduced fuel bills.

Housebuilders need to consider that more financial investment is generally needed in the building structure (for instance better insulation, double glazing, larger radiators or underfloor heating) to enable a renewable technology like this to be installed and operate at their optimum efficiency.


As heating technology continues to move forward and innovation delivers higher efficiency ratings, we are seeing clever hybrid options which combine heating fuels such as oil with a heat pump, ultimately giving the best of both worlds.

A hybrid, such as the Grant VortexAir, is specifically a unit that couples together a VortexBlue blue flame oil-fired condensing boiler (in a 15-21kW or 21-26kW output) with a 16kW Aerona3 inverter driven air source heat pump, in either one compact casing with just a single flow and return connection into the house, or as two separate units, with the boiler section installed internally. This allows the oil boiler to be fitted first as a stand-alone unit, replacing an old appliance and providing immediate heat and hot water for the householder. The heat pump can then be fitted externally, maybe at a later date, giving householders an option to tap into renewable energy and the benefits it can present. The combination of an oil boiler with a renewable appliance maximises the system’s efficiency, delivering reliable, effective heating.

Solar thermal

Solar Thermal is another popular renewable technology that could be incorporated into an oil, heat pump or hybrid heating system as a way of further reducing annual fuel bills and carbon emissions. It is very reliable and operates from both direct and diffused sunlight, so perfectly designed for the UK’s varied weather. It can achieve as much as a 70% saving in water heating costs. Roof mounted solar collectors transfer heat to the cylinder where hot water is produced. With the Grant Solar system, our patented high efficiency collector can be installed using either an ‘on-roof’, ‘in-roof’ or ‘flat-roof’ arrangement and maintenance is kept to a minimum with the use of self-cleaning glass. Grant Solar is available in kit form complete with all the required components.

Both oil and renewable heating systems provide significant benefits to off-gas properties. The innovation being brought to the market by companies such as Grant, are adding value to homes and will be supported for many years to come.

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