Around 41,000 homes in Devon are heated by oil. Most of them are in rural areas, off the gas grid, and have been on oil for decades. For many of these households, the question of whether to switch to a heat pump has moved from something vague on the horizon to something worth properly investigating.

This post sets out the honest case for switching, what the Boiler Upgrade Scheme means in practice, what the installation actually involves, and what rural Devon homeowners specifically need to think about before committing.

Why oil-heated homes are particularly strong candidates

The financial case for switching from oil to a heat pump is stronger than for switching from mains gas, and that gap has widened over recent years.

Oil prices are volatile. They track global commodity markets and have spent much of the last three years at elevated levels. Unlike gas, there is no Ofgem price cap protecting oil users from market swings. Households on oil have faced significant uncertainty about what heating will cost from one year to the next, and that uncertainty is not expected to resolve.

A heat pump produces three to four units of heat for every unit of electricity it consumes. Even with electricity more expensive per unit than oil, an efficiently designed and well-operated heat pump is competitive on running costs with oil at current prices for many Devon households, and significantly cheaper for those on time-of-use electricity tariffs or with solar panels.

The BUS grant of £7,500 is also specifically well-suited to oil-heated homes. The scheme was designed with off-gas households in mind. Replacing a fossil fuel system is a condition of the grant, and oil qualifies. The grant reduces the upfront cost of switching in a way that meaningfully changes the financial picture compared with doing it entirely at your own expense.

The Boiler Upgrade Scheme in practice

The Boiler Upgrade Scheme provides a grant of £7,500 towards an air source heat pump installation for homeowners in England and Wales who are replacing a fossil fuel heating system. Oil qualifies. The grant is applied by your MCS-accredited installer on your behalf and deducted from the installation cost directly. You do not receive the money and then pay the installer. Your installer applies for the voucher, the voucher is issued, and the cost you see on your invoice reflects the grant already applied.

There is no income test. The scheme is available to owner-occupiers regardless of household income. Landlords can also apply in some circumstances.

The voucher is valid for a limited period once issued, typically around three months, so installation needs to follow application within that window. Your installer will manage the timing as part of the project.

One practical point worth knowing: the BUS requires that your property has a valid EPC with no recommendation to install loft or cavity wall insulation, unless that insulation is not technically feasible. If your EPC is out of date or does carry one of those recommendations, your installer will identify this at survey stage. In most cases it is resolvable, but it is better to know early.

What switching from oil actually involves

The installation of an air source heat pump in a rural Devon property involves more than swapping one heat source for another. Understanding the full scope upfront avoids surprises.

Removing the oil system. The oil boiler, flue, and typically the oil tank are decommissioned and removed. Oil tank removal has its own requirements around safe drainage and disposal. Your installer will advise on whether the tank removal is included in scope or requires a separate contractor.

Installing the outdoor unit. The heat pump’s outdoor unit extracts heat from the air. It needs to be positioned where it can draw in air freely, where the noise level is acceptable at habitable windows and boundaries, and where the refrigerant pipework run to the indoor components is manageable. Rural Devon properties almost always have sufficient outdoor space for this, which is one advantage over urban terraced properties.

Refrigerant pipework. Insulated pipework runs from the outdoor unit through the wall into the plant room or utility space where the indoor components are located. This is a straightforward part of the installation for most rural properties.

The hot water cylinder. A heat pump requires a hot water cylinder. If your current oil system uses a cylinder, it may need replacing with a larger, better-insulated model suited to heat pump operation. If you currently have a combi boiler arrangement without a cylinder, installing one is part of the project and requires space planning.

Radiators and heat emitters. This is the part of the installation that causes the most uncertainty, and it is worth being direct about it. Heat pumps work most efficiently at lower flow temperatures than oil boilers. A typical oil boiler might run at 70 to 80 degrees. A heat pump running efficiently might operate at 35 to 45 degrees. Radiators sized for high-temperature boiler operation may not deliver enough heat output at the lower temperature a heat pump uses.

At survey stage, each radiator is checked against the room’s heat loss requirement at the proposed flow temperature. In some rooms, particularly larger rooms or those with high heat loss, a radiator upgrade is needed. In well-insulated rooms with existing large radiators, the existing emitters are often sufficient. The outcome depends entirely on the specific property, which is why a proper heat loss calculation is essential rather than a general reassurance that it will probably be fine.

Electrical supply. A heat pump draws more electrical load than an oil boiler. Your installer will check whether your existing consumer unit and supply can accommodate the new load. In most cases this is straightforward. Occasionally a consumer unit upgrade is needed.

Controls and thermostat. Heat pumps operate differently from oil boilers and are controlled differently. A weather compensation controller, which adjusts the flow temperature based on outdoor conditions, is the standard approach and makes a meaningful difference to efficiency. Your installer will configure the controls as part of commissioning and should give a clear handover explaining how the system works and how to get the best out of it.

Insulation: what is actually required and what helps

The BUS grant requires, as noted above, that the property does not have an outstanding EPC recommendation for loft or cavity wall insulation that is technically feasible. Beyond that requirement, the question of how much insulation is needed is a design question rather than a regulatory one.

A heat pump can be installed in a property that is not perfectly insulated. Many rural Devon farmhouses with solid stone walls are heated by heat pumps and perform well. The key is that the system is designed to match the actual heat loss of the building as it is, not an idealised version of it.

That said, insulation improvements that reduce heat loss allow the heat pump to run at lower flow temperatures, which improves efficiency and reduces running costs. The improvements that tend to give the best return in rural Devon properties are:

Loft insulation. The single most cost-effective improvement in almost any property with a loft. Heat rises, and an uninsulated or poorly insulated loft allows a significant amount of generated heat to escape. This should be addressed before or alongside the heat pump installation if it has not been done already.

Draught proofing. Sealing gaps around windows, external doors, floorboards, and pipe penetrations reduces heat loss significantly for modest cost. Rural Devon properties, particularly older farmhouses and cottages, often have considerable draught infiltration that is easy to address. Draught proofing has a fast return on investment and makes the living environment noticeably more comfortable regardless of what heating system is fitted.

Hot water cylinder insulation. A modern pre-insulated cylinder retains heat far more effectively than older copper cylinders. Given that the heat pump heats the cylinder directly, a well-insulated cylinder means the heat pump runs less frequently to maintain the water temperature, which reduces electricity consumption.

Wall insulation. Solid wall insulation, whether internal or external, reduces heat loss from the walls significantly but involves more disruption and cost than the measures above. It is worth considering as part of a longer-term plan, particularly if the property is also eligible for funding through the Warm Homes Local Grant. It is not always a prerequisite for a heat pump installation, but it does improve the outcome.

What rural Devon homeowners specifically need to think about

Rural properties have some characteristics that come up repeatedly in heat pump surveys in this area, and it is worth covering them directly.

Oil tank removal and oil disposal. If you have a large bunded oil tank that has been in place for many years, the decommissioning process involves draining remaining oil, cleaning the tank, and arranging appropriate disposal. The timing of this relative to the heat pump installation needs to be planned so you are not left without heating during the transition. Your installer should map this out clearly.

Electricity supply reliability. Rural properties in Devon experience power cuts more often than urban ones. A heat pump without any backup provision will lose heating during an outage, just as an oil boiler loses ignition without mains power. If power cut resilience matters to you, discussing battery storage with Emergency Power Supply configuration at the design stage is worthwhile. See our home battery storage guide for more on this.

Single-phase versus three-phase supply. Most rural domestic properties have a single-phase electricity supply. Most domestic heat pumps are designed for single-phase supply and this is not an issue. Larger heat pumps for bigger properties may require three-phase supply, which some rural properties already have. Your installer will confirm this at survey stage.

LPG rather than oil. Some rural Devon properties use LPG rather than oil. LPG also qualifies for the BUS grant in the same way as oil. The installation process is essentially the same.

Combining with solar. Rural Devon properties with open aspects and good roof orientations are often excellent candidates for solar panels. Adding solar to a heat pump installation, or planning solar for the near future when switching to a heat pump, makes considerable financial sense. Solar reduces the heat pump’s running costs by supplying some of its electricity demand from generation you own. Our guide to solar panels and heat pumps together covers this in detail.

Planning for listed buildings and conservation areas. Devon has a large number of listed buildings and conservation area properties in rural settings. Permitted development rights for heat pumps do not apply to listed buildings. A heat pump installation on a listed property requires listed building consent, and the application needs to address the position of the outdoor unit, refrigerant pipework routing, and any modifications to the building fabric. This is manageable but takes longer than a standard installation, and the survey should identify it before any quote is given.

Is the timing right to switch?

The BUS grant is funded until 2030, so there is no immediate deadline. But there are good reasons not to leave the decision indefinitely.

If your oil boiler is ageing and approaching the point where it will need significant repair or replacement, switching to a heat pump while the BUS grant is available makes considerably more sense than replacing it with another oil boiler at full cost and then switching a few years later when the financial case may look different.

If you are already planning other works on the property, such as a kitchen or bathroom renovation, a roof replacement, or significant redecoration, the disruption of heat pump installation and any radiator upgrades is easier to absorb alongside other work than as a standalone project.

If you are considering solar panels, doing a combined survey for heat pump and solar at the same time allows the solar system to be sized around the heat pump’s electricity demand from the outset, which produces a better-integrated system than adding solar as an afterthought.

The honest summary

Switching from oil to a heat pump makes strong financial and practical sense for many rural Devon households, particularly when the BUS grant is factored in and the installation is properly designed around the actual property rather than a template.

The cases where the outcome is less straightforward are real: a property with very high heat loss and no practical insulation options, a listed building where planning consent will be needed, or a property where the electrical supply needs upgrading. None of these are reasons to rule it out without looking. They are reasons why a proper survey by an experienced installer is the essential first step.

A survey costs nothing, takes a couple of hours, and gives you a specific, honest answer about your property rather than a general one about switching from oil in Devon.

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