Energy bills and new homes: what Sizewell C means for UK property costs
The government's decision to fund the Sizewell C nuclear plant in Suffolk has sparked serious concerns about who will pay the bill. A report from Parliament's public accounts committee warns that taxpayers and consumers could face costs totalling almost £48bn over the coming century. For homeowners already struggling with mortgage repayments, this raises an uncomfortable question: how much more expensive is energy going to become?
The numbers are substantial. According to the watchdog report, bill payers face an extra £9.8bn to fund construction before 2040, plus a further £12bn spread across the plant's 60-year operating life. That's a significant commitment from households already managing higher energy costs and mortgage repayments at current rates.
How this affects your monthly budget
Right now, UK homeowners are contending with considerable financial pressure. With average mortgage rates sitting at 6.58% for two-year fixed deals and 5.13% for five-year terms, many households are already paying substantially more than they were two years ago. The Bank of England base rate remains at 3.75%, leaving little room for immediate relief on borrowing costs.
Energy bills form a separate but equally important part of the household budget. If the costs of Sizewell C construction and operation are passed to consumers through energy bills rather than purely through taxes, this becomes another monthly outgoing to worry about. The government has argued that once operational, Sizewell C could save £2bn annually across the energy system. Whether those savings actually reach individual households remains an open question.
The timing matters too. With UK house prices growing at just 0.9% annually and inflation holding at 3.5%, households are already seeing their property wealth barely keeping pace with general price rises. Adding significant energy bill increases into the equation changes the financial equation for anyone considering moving home or refinancing a mortgage.
A question of fairness
One of the most striking elements of the public accounts committee's criticism is about risk distribution. The committee chair, Sir Geoffrey Clifton-Brown, highlighted that "the high level of risk borne by taxpayers and consumers for the construction of Sizewell C is extraordinary." Meanwhile, private investors including Centrica, Canadian investment group La Caisse, and others hold stakes but face limited downside risk. If costs spiral beyond the £38bn baseline estimate, ordinary bill payers bear most of the burden. Private backers only need to contribute an extra £30m if things go wrong.
This asymmetry is worth understanding if you're buying or selling property. When infrastructure projects dump costs onto bill payers, it effectively reduces disposable income across the country. That impacts how much people can afford to spend on housing, which in turn affects property values and market activity.
What comes next for homeowners
The government has defended the project, arguing that investors are incentivised to complete construction as cheaply and quickly as possible under the deal terms. The project already has over 2,000 workers on site, suggesting momentum is building. Whether that translates to cost discipline remains to be seen, but early progress is at least concrete.
For homeowners, the practical advice is straightforward. If you're considering locking in a mortgage rate, energy costs should factor into your affordability calculations. Current fixed-rate deals at 6.58% for two years and 5.13% for five years are worth comparing carefully, especially if you're planning to stay in your home for several decades. The longer your time horizon, the more important it becomes to think about future energy costs.
If you're selling a property, emphasise energy efficiency improvements you've made. Better insulation, modern heating systems, and renewable energy installations become more valuable as energy costs potentially rise. First-time buyers should factor long-term running costs into their purchase decisions, not just mortgage repayments.
The Sizewell C project may deliver long-term benefits through cleaner energy and stable power supply. The debate now centres on whether taxpayers should shoulder most of the financial risk to get there. Either way, understanding how major infrastructure decisions affect your bills and property finances is increasingly important for making sound long-term decisions about your home.