​The UK Government has a net zero goal in place for 2050, which requires greenhouse gas emissions to be reduced to as close to zero as possible, with any remaining being balanced out by removing an equivalent amount.  Many impacts of climate change are already being detected: leading scientists have stated that the record 40⁰C temperatures in the UK in July 2022 would have been "almost impossible" without human-induced climate change.  All sectors of the UK economy therefore must decarbonise if we are to achieve net zero.

With the construction and operation of buildings responsible for around 38% of global carbon emissions¹, we have an important role to play in ensuring every aspect of our buildings are examined, and carbon impact reduced.  As you would expect, heating and hot water have a significant bearing on overall carbon emissions of a building.

The ‘Heat and Buildings Strategy’, launched in October 2021, is the UK Government’s plan to decarbonise virtually all heat in buildings, which is fundamental to the Net zero goal.  At the heart of this strategy is phasing out the use of fossil fuels to heat buildings by 2035, whilst increasing the application of low carbon products, fuels and energy sources.  This date is significant as an interim target has been established for 2035 to reduce emissions in the UK by 78% by compared to 1990 levels. 

The uplift of Building Regulations’ ‘Conservation of fuel and power: Approved Document L’, introduced in December 2021 and in force as of June 2022, is the legislative method adopted to ensure new buildings will be fitted with low-carbon heating and high levels of energy efficiency achieved, targeting on average a 27% decrease in CO2.

Heat Pumps: The Readily Available Solution

So how are we to achieve decarbonisation of our heating?

There has been much talk of hydrogen as our saving grace, but the reality of hydrogen as a fuel source is some way off in the future with one of the major stumbling blocks to its use being the infrastructure to deliver it.  Thankfully, we do have a viable alternative that is available in the here and now: heat pumps.

A heat pump is an appliance that extracts heat energy from the environment and upgrades it to useful heat for central heating and domestic hot water.  They are available in air source, ground source, water source and exhaust air formats.  Air source are the most popular as they can be used in the widest range of building types and locations, and work very well with underfloor heating and radiators, as long as they are sized correctly.  They can also be integrated with most renewable energy sources such as solar PV.

Air Source Heat Pumps for Versatility & Effectiveness

With a compact design, air source heat pump technology is one of the most versatile and cost-effective low carbon appliances on the market.

An air source heat pump extracts heat energy from the external air – even when temperatures are as low as -20°C - and upgrades it to useful heat for central heating and hot water. Two types of air source heat pumps exist: monobloc and split systems. A monobloc system has all the components in a single outdoor unit, with pipes carrying water to the central heating system and a hot water cylinder inside the building. A split system separates the components between indoor and outdoor units.

Monobloc Heat Pump Advantages

A monobloc heat pump system has a number of advantages, the main one being that all of the refrigerant components are contained within the outdoor unit, meaning the central heating system and the DHW coil are directly connected to the external fan unit. No F-Gas qualification is required to install a monobloc. However, due to the larger size of a monobloc unit it is normally ground mounted and, to minimise the higher heat losses, the fan unit ideally needs be located as close to the property as possible for maximum efficiency.

Hamworthy’s new Tyneham range of air source heat pumps are based on a monobloc design and provide one of the best seasonal coefficient of performance (SCOP) ratings on the market.  SCOP is the average ratio of heat produced, relative to each unit of electricity consumed in the heat pump, over one year.  Tyneham heat pumps also benefit from the use of R32 refrigerant, which has a reduced GWP (global warming potential) compared to some alternative refrigerants.

Heat Pumps Role in Reaching Net Zero

how heat pumps work

With hydrogen fuelled heating systems not a practical solution at this time, heat pumps are a fundamentally important decarbonisation solution, and play an important role in our drive to net zero.

According to the Carbon Trust, heat pumps used for heating can offer carbon emission savings of around 30% when compared to conventional natural gas boilers. When heat pumps are partnered with a renewable electricity supplier, heat generation is 100% carbon neutral.

Heat pumps also enable significant savings to be made on running costs when compared to alternative fuel solutions, as well as protecting building owners against fluctuations in energy costs.  Whilst the capital outlay of buying and installing a heat pump are considerably higher than traditional boiler systems, incentives are available to reduce these.

SCOP Heat pump seasonal coefficient of performance

Government Heat Pump Targets

All of this is very positive news, but heat pumps will only impact net zero if we install enough of them and if the system is designed and installed correctly.  The Committee on Climate Change has said that to meet the commitment to reach net-zero by 2050, 19 million heat pumps will need to be installed and that hybrid heat pumps should be widely used by 2035.  The Government has a commitment to install 600,000 heat pumps per year by 2028, but UK charity Nesta, which describes itself as ‘an innovation agency for social good’, claims we are well off this mark.

Despite a slow start, uptake of heat pumps is increasing, especially in the commercial sector.  However, what’s not increasing is the number of trained heat pump engineers.  Nesta believes there are around 3,000 trained heat pump engineers in the UK, each fitting between 20 - 25 heat pumps per year.  But to meet the goal of 600,000 heat pumps per year by 2028, a further 27,000 installers will be required!  It is calling for government support to finance training in this sector, deliver a clear route to become a heat pump engineer and demonstrate commitment to this sector.

Getting Back on Track

Decarbonisation of the UK economy is essential if we are to stand any hope of achieving Net Zero by 2050 and keep temperature rises below 1.5°C to avoid the very worst impacts of climate change.  Even with this target we are set to see ongoing heatwaves, fires and droughts in coming years.  We don’t have a magic wand to achieve this, but we do have a number of practical solutions at hand, heat pumps being one that is readily available.  By moving away from fossil fuels and switching to renewable fuel powered systems such as heat pumps, we can make a difference; we must make a difference.

¹ 2019 Global Status Report for Buildings and Construction Sector, United Nations Environment Programme.