Some customers have been told by suppliers that oil is not currently available in their area, while others are facing sharply increased costs compared with quotes they received just weeks ago.
Mr Smith said: "We are already hearing from customers who are worried, and rightly so. Some have had deliveries cancelled altogether, while others are being asked to pay significantly more than they were originally quoted.
"For people on fixed incomes who rely on oil to heat their homes, that is a really difficult position to be in and it is happening very quickly."
Unlike households on standard energy tariffs, those who rely on heating oil sit outside the energy price cap set by Ofgem, meaning they have no protection from sudden price spikes.
Around 1.5 million homes across the UK rely on heating oil, with rural communities particularly affected as many properties do not have access to mains gas.
With many customers now asking whether it is time to switch to an alternative system, Mr Smith is urging homeowners to think carefully before making any major decisions. In the meantime, he says there are practical steps oil-heated households can take right now to make their supply go further and protect what they have.
Mr Smith said: "While prices are high, it makes sense to get as much as you can out of the oil already in your tank. Having your boiler serviced by an OFTEC-registered engineer means it is running at its most efficient and not burning through fuel unnecessarily. Bleeding your radiators, checking your pressure and upgrading to modern high-efficiency equipment where possible all make a real difference. Smart controls and thermostats are also worth investing in as they give you much greater control over how and when your heating runs, which reduces waste.
"We would also urge people to think about security. Unfortunately, as prices rise, oil theft tends to rise with it. Tank alarms are now widely available and are a relatively small investment that could save a significant amount."
With many customers now asking whether it is time to switch to an alternative system altogether, Mr Smith is urging homeowners to think carefully before making any major decisions.
Alternatives to oil include air source heat pumps, ground source heat pumps, solar thermal systems, solar panels paired with electric heating, and in some cases connecting to mains gas where this is available. However, Mr Smith said none of these options is suitable for every home.
Mr Smith added: "It is completely understandable that people are looking at their options right now, and there are some good ones out there.
"For those considering an air source heat pump, the government's Boiler Upgrade Scheme currently offers a £7,500 grant and this has been confirmed until March 2030. The 0% VAT on heat pump installations is also currently in place until March 2027, which helps make the upfront cost more manageable.
"But heat pumps, solar and other technologies are not the right answer for every property. Each system has its own costs, requirements and limitations. What works well for one home may not work at all for another.
"My advice is to take proper independent advice before committing to anything. We would always rather give a customer an honest answer than push them towards a quick decision they might regret."
Custom Heat has been serving homes and businesses across the Midlands and South West since 1980. The company employs around 70 people and offers gas boiler installation and servicing, heat pump installation, plumbing, air conditioning and electrical services.
