The common myths around low carbon technologies
Myth 1 - To achieve net-zero heating and cooling by 2050, all homes will need to be retrofitted to Passivhaus standard.
Firstly, it is important to recognise that achieving the very low energy demands that Passivhaus achieves, without decarbonising the energy source, a property will still not achieve zero carbon emissions from their heating system, regardless of what type it is.
Secondly, Passivhaus is a fairly well-known standard which is often talked about, but its specificity to new build is often misunderstood.
When we talk about retrofitting homes to very high thermal efficiency standards, it’s actually EnerPHit that we mean, which is an equivalent standard and is designed with retrofit in mind. While a home that is retrofitted to EnerPHit standard will use more energy than a new build home built to Passivhaus, both standards result in highly insulated homes with low heating and cooling energy demand. But as I mentioned above, unless the energy source is zero carbon, the home will still produce carbon emissions from it’s heating system.
Achieving EnerPHit often required deep-retrofit, which can cost between £800-£1000/m2. For an average UK home of 76m2, this comes in at a cost of between £60,800 - £76,000. Against the average house price of £251,500, this represents costs equivalent to up to 30% of the property’s value.
These super low energy homes can be very cheap to run, but achieving these standards isn’t necessary for zero carbon heat, and more cost-effective methods exist.
Myth 2 - The cost of deep-retrofit works is prohibitively expensive for landlords or private homeowners to afford.
Not all homes in the UK will need to undergo deep-retrofit in order to achieve the net-zero carbon goal.
If a home is already well insulated and has modern double glazing, then a retrofit including just an air source heat pump for heating and hot water, and photovoltaic solar panels can easily convert the home to net-zero carbon.
There are also financial incentives for UK property owners which can significantly reduce the cost of equipment such as air source heat pumps.
RHI (renewable heat incentive) has been around since 2014 and makes quarterly payments to the property owner for heat energy generated from renewable sources, for a period of seven years.
The scheme will close to new applicants at the end of March 2022 so it’s a really important incentive to be capitalising on while it’s still available.
In December 2020, Which? estimated that for an average three bedroom detached home, RHI payments over a seven year period could be up to £12,912, against a cost to install an air-source heat pump of between £9,000 and £11,000.
When RHI scheme closes, it is expected to be replaced by the Clean Heat Grant, which will give £4,000 upfront off the cost of air source heat pumps. Additionally, the Government is expected to announce a replacement to the Green Home Grant scheme which is also expected to include funding for zero carbon heat technologies such as air source heat pumps.
Liberty is a founding member of NetZero Collective, and research done by collective has shown that a well-insulated three-bedroom semi-detached home in the UK can be retrofitted with an air source heat pump and solar photovoltaic panels (solar PV) for around £12,000 for landlords investing at large scale, or about £2,000 more for a private homeowner who cannot get the savings available from mass install.
This can make well-insulated homes net-zero carbon and reduce the household energy bills by up to a third. Adding home battery storage to the home can cost an additional £4,500 but can reduce household energy bills even further, with an estimated saving of two thirds.
These figures are estimated, based on large scale deployment programmes, however we’re currently working with NetZero Collective and Crawley Borough Council to deliver a decarbonisation scheme which will prove this model. On this small scale, we have already achieved an average cost of just £23,500 per home to fully decarbonise the homes so we are confident that at scale our estimates will hold up. But even at £23,500, this is considerably more affordable than the projected costs to achieve EnerPHit for an average UK home, and still reduces the fuel bills for the resident.
Myth 3 – Air-source heat pumps use electricity which is expensive, so it’s going to cost a lot to heat my home.
While it’s true that electricity is more expensive than gas, air source heat pumps are highly efficient, so they still result in significantly lower bills when installed in well-insulated properties and combined with solar PV.
On average they’re 300% efficient, meaning the will return 3kW of heat energy for every 1kW of electricity used. Compared to a modern gas boiler which is 90% efficient and provides 0.9kW of heat for every 1kW of gas energy used.
Furthermore, by installing solar PV panels on the roof of the home as part of a decarbonisation retrofit, the home can generate some of its own electricity. This can reduce home energy bills by a third compared to the same house heated using a gas boiler.
For property owners wanting to go even further, and reduce resident fuel bills even more, home battery storage can be added at a cost of around £4,500. Adding home battery storage to the system can reduce the resident’s home energy bills by another third, which can be great news for landlords where fuel poverty for their residents may be a concern.
Homes with battery storage could also make additional savings by switching energy providers to a time-of-use energy tariff, such as Agile Octopus, by Octopus Energy. This would allow them to buy electricity when it’s cheap and store it in their battery to use in their home when electricity prices are higher.
Myth 4 - There are not enough net-zero retrofit installers, so we’re never going to be able to retrofit enough homes to achieve the 2050 net-zero economy deadline
While there is some truth in this, as the current infrastructure hasn’t yet caught up with future demand, the picture is changing rapidly and by dispelling these myths around low carbon heat and growing confidence in the market, the economics of delivery will only improve.
Liberty has over 500 Gas Safe registered engineers working around the country, and we’re not alone. Gas heating is big business, and the skills of this workforce will still be vital to support the transition to low carbon heating. If an air source heat pump is being installed to replace a gas boiler, then a Gas Safe registered engineer will be needed to decommission the system being removed. But why shouldn’t the same engineer also install the new heating system?
So when considering whether there is a lack of skilled installers, my view is that we have the people ready and waiting, and business such as Liberty who can invest in training for existing employees to create future proof jobs to meet the future demand for retrofit.
How we invest in training will be key, and we are looking at multiple options for this, including a ‘centres of excellence’ model in partnership with NetZero Collective.
Myth 5 - Using electricity to heat my home won’t make my home zero carbon if my electricity is made by burning coal
In February 2021, the UK Government reported that just 1.8% of electricity in the UK was generated by burning coal in the previous three months. 40.6% of electricity was generated from gas, and 37.7% from renewable sources, and 19.3% from nuclear.
This means that during this period, 57% of the electricity generated in the UK came from zero-carbon sources (renewable + nuclear).
Residents wanting to be net-zero carbon can purchase 100% renewable energy easily, and many energy comparison websites have filters allowing customers to find these deals.
Any resident with solar PV on their roof may also generate more electricity than their home uses when averaged across the year. Whilst some of this energy will be exported to the National Grid in the sunny summer months and the resident importing electricity from the grid during the winter when solar PV will generate less electricity, if the overall generation of the solar PV system is more than the home uses in the year, the home is also considered to be net-zero carbon.
However even residents who just want the cheapest energy prices available will still reduce their emissions significantly at the point of retrofit and their emissions will continue to fall over the years as UK energy suppliers and the electricity grid decarbonise to meet the 2050 net-zero carbon deadline.