Frequently asked questions about replacing an oil boiler
Direct answers to the things Scottish rural homeowners ask us most. No hedging, no sales language. If your question is not here, call us and we will answer it straight.
Key facts
- 12 questions answered on cost, insulation, radiators, hot water and installation time.
- The Boiler Upgrade Scheme is England and Wales only — it does not apply in Scotland.
- A heat pump needs a hot water cylinder — it does not provide instant hot water like a combi.
- The system size is decided by a heat loss calculation, not the floor area.
- Air source heat pumps work in Scottish winters if the system is correctly sized and the house is insulated.
Last updated: 28 October 2026
Can a heat pump replace an oil boiler in Scotland?
Yes, if the house is well insulated with suitable radiators or underfloor heating and space for a hot water cylinder and outdoor unit. A room-by-room heat loss calculation confirms whether it will work.
Is there a boiler upgrade scheme in Scotland?
No. The Boiler Upgrade Scheme is England and Wales only and does not apply in Scotland. Do not assume any scheme applies until it is confirmed in writing for your property.
How much does an oil to heat pump conversion cost in Scotland?
Typically between £8,000 and £15,000 depending on the property, the system size and the work required. You receive a written quotation after a survey, never a single price over the phone.
Do I need better insulation before getting a heat pump?
Usually yes. A heat pump runs at a lower flow temperature than an oil boiler, so the fabric of the building has to hold the heat. Poor insulation is the single most common reason a heat pump disappoints.
Will my existing radiators work with a heat pump?
Some will, some will not. A heat pump runs at a lower flow temperature, so some rooms may need larger radiators or underfloor heating. A room-by-room heat loss calculation decides this, never a rule of thumb.
What happens to my hot water when I switch from oil?
You need a hot water cylinder because a heat pump does not provide instant hot water like a combi boiler. Your existing cylinder may work or may need replacing, and pipework may need adjustment.
How long does an oil to heat pump installation take?
Typically two to four days for a straightforward property, longer if radiators, pipework or a cylinder need replacing. You are never left without heat overnight.
What size heat pump do I need for my house?
The size is decided by a room-by-room heat loss calculation, not the floor area. Two identical-looking houses can need different sizes because of insulation, glazing and exposure. A surveyor measures every room before the size is confirmed.
Can a heat pump work in a Scottish winter?
Yes, if the system is correctly sized and the house is well insulated. Air source heat pumps work down to well below freezing, but the colder it gets, the harder the unit works and the more electricity it uses. Insulation is what keeps running costs manageable.
Do I need a new hot water cylinder?
Not always. Your existing cylinder may be compatible if it is large enough and has a suitable coil for the lower flow temperature. The surveyor will check this and it will be stated on the quotation.
Where does the outdoor unit go?
The outdoor unit needs air around it and a sensible place to sit, ideally sheltered from prevailing wind. It can go on the ground or mounted on a wall. The surveyor will suggest the best position during the visit.
Will I still need my oil tank after switching?
No. Once the heat pump is installed and commissioned, the oil boiler and tank are decommissioned. You may choose to keep the tank temporarily, but it will no longer be needed for heating.
Have a question we have not answered?
Call us or fill in the form. We answer questions honestly, including telling you when a heat pump is not the right choice for your house.
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Last updated: 28 October 2026. Reviewed by the Scottish Energy Efficiency team.