Planning heat pumps: comparing sources, heating replacement and costs
A heat pump uses environmental heat and electricity to provide warmth for a building. The complete system matters: source, appliance, distribution and hot water need to work together. A useful quote considers actual requirements and necessary site work rather than an equipment price alone.
Distinguish advice, a heating change and equipment replacement
Start with the result you need. Advice on alternatives, complete heating replacement and replacing an existing heat pump involve different services. Have the planning and installation work you are actually commissioning specified.
| Commission | Clarify the result and scope |
|---|---|
| Advice and choice of options | Assessment of the existing system, suitable options and next checks; agree detailed design and installation separately. |
| Switching from another heating type | Plan the new system with its source, connections, hot water and removal work; identify the responsibilities of the businesses involved. |
| Replacing an existing heat pump | Check reuse of the source, tanks and distribution; expressly identify compatible parts and required modifications. |
The heat source needs to be usable at the site
Air-to-water heat pumps use outdoor air and supply a water-based heating system. Brine-to-water arrangements can use ground probes; water-to-water systems can use a suitable water source. Each option needs its own assessment. Available land alone confirms neither permission to drill nor an adequate source.
Selection depends on the building, heating demand, space and local possibilities. You do not need to choose a technology before initial advice. An existing ground probe or other source should be checked for suitability for the new complete system before replacing equipment.
| Approach | What planning needs to establish |
|---|---|
| Air-to-water | Positioning, air routes, noise and connection to heating. |
| Brine-to-water | Usable source, sizing and necessary checks for probes or collectors. |
| Water-to-water | Availability and permitted use of the water source. |
| Air-to-air | Direct room-air heating rather than connection to water-based emitters. |
| Existing source | Suitability for replacement equipment, intended use and operation. |
Consider demand and planned renovations together
Heated floor area is a starting point, not a complete capacity calculation. Insulation, windows, location, use and hot-water demand affect sizing. Known past consumption can help but needs interpretation in the building’s context. A fixed kilowatt capacity per square metre would be inaccurate.
If insulation, new windows or an extension is planned, take this into account. Equipment selected today should also suit foreseeable use. For several dwellings, shared supply and coordination with occupants matter. The professional establishes peak demand and operating arrangements; customers do not need to calculate a heat load.
Radiators do not automatically rule out a heat pump
Underfloor heating can operate at relatively low heating-water temperatures. Existing radiators can also be suitable where output and required temperatures fit the building. Complete radiator replacement is not always necessary, but every older distribution system is not automatically suitable either.
Have the emitters, pumps and settings checked to establish what can be retained or needs adjustment. Hydraulic balancing can support coordinated operation but does not replace appropriate sizing. Customers state the known heating type and distribution; flow temperatures and technical changes are assessed by the business.
Include positioning, connections and removal in the plan
For air-to-water systems, position and airflow affect installation. Airborne noise, vibration, neighbouring windows and maintenance access belong in the plan. A quiet product-sheet value alone does not confirm a suitable site. An outdoor unit also needs appropriate mounting and professionally planned condensate or defrost-water drainage.
Heating replacement can involve electrical work, new pipework, storage and removing the previous system. Removing an oil boiler is not the same task as decommissioning and disposing of a tank. Have these tasks specified expressly. During the heating season, agree the interruption and any temporary heating solution.
Clarify approvals and funding conditions early
Procedures and responsibilities depend on the heat-pump type, location and project. Notification arrangements can apply to some projects; others need permission or further checks. Drilling and water use have additional prerequisites. A suitability map or neighbour consent does not automatically replace a required approval.
Funding conditions vary with the programme, existing heating and planned installation. Check deadlines and requirements before ordering and starting work. Particular quality evidence may be relevant to a programme. Establish who prepares documents and the application; a subsidy or particular certificate is not automatically promised or included in every quote.
Compare heat-pump costs for the complete project
Cost depends on more than equipment. Developing the source, positioning, storage, electrics and distribution changes can be substantial items. An offer excluding drilling cannot be compared directly with a complete ground-probe arrangement. Check scope, VAT and exclusions before comparing prices.
When replacing a heat pump, infrastructure may be retained but needs assessment. A low equipment price does not compensate for missing removal, connection or commissioning work. Ask for an understandable complete scope and clear arrangements for additional tasks that only become apparent during execution.
Economics depend on investment, subsidies, electricity tariff, operation and maintenance. Laboratory efficiency is not a guaranteed annual consumption figure. Solar PV also does not automatically cover all winter electricity requirements. Compare transparent assumptions and distinguish expected savings from promised services.
For an operating-cost estimate, request the assumed heat demand, electricity consumption and price, maintenance and any backup heating. Compare options over the same period using the same price assumptions. Show the project price before funding and the expected subsidy separately; financing also needs to match payment dates.
| Cost group | Comparable information |
|---|---|
| Equipment and storage | Models, capacity sizing and existing or new tanks. |
| Heat source | Necessary development and existing infrastructure. |
| Installation and connections | Positioning, pipes, electrical work and auxiliary equipment. |
| Existing system | Removal, disposal and distribution changes. |
| Commissioning | Settings, checks, documentation and instructions. |
| Other assessments | Applications, evidence and separately agreed service. |
Information for a useful first quote
Known building information and your plans are enough to get started. You do not have to determine a standard category, drilling depth or refrigerant quantity.
Existing consumption bills, plans, system details or an energy report can help where available. New surveys or drawings are not routinely needed for an initial enquiry; the business establishes what else the particular design and approval process require.
Example: “We want to replace the oil heating in our detached house built in 1985, with about 150 m² of heated floor area. The rooms are heated by radiators; we need space heating and hot water for three people. Consumption bills for the past two years are available, and window renovation is planned. We have not chosen a heat-pump type and do not need cooling. Please assess the existing emitters and offer a complete solution including electrical work, removal and separately itemised oil-tank removal. Please also clarify application preparation, possible funding and any heating interruption.”
- Project. Distinguish a new building, changing the heating type and replacing an existing heat pump.
- Building. State use, approximate heated floor area and the number of dwellings involved.
- Existing system. Share the known heating system and heat emitters.
- Requirements. State heating, hot water, any desired cooling and preferred timing.
Take over a coordinated complete system
After installation, controls, heat distribution and hot water should be set for intended operation. Clear guidance and recorded commissioning help with daily use and future work. Maintenance and repair are subsequent services, not automatically included without limit in the purchase.
Agree a handover check of the functions ordered: heating, hot water and cooling only where commissioned. Have heating schedules, temperature settings and fault reporting explained. Record outstanding work, responsibilities and deadlines.
Handover includes the agreed operating instructions, system data and commissioning record; have promised evidence and certificates listed individually. Establish who checks settings and operation after the first heating season and whether that follow-up is included. A brief functional test does not establish annual consumption.
- Assess the situation. Have demand, existing heating and the site assessed professionally.
- Define the solution. Agree source, positioning, distribution and necessary approvals.
- Compare proposals. Check the same complete scope, prerequisites and exclusions.
- Install and set up. Agree installation, commissioning, handover and any follow-up check.
Frequently asked questions
Can a heat pump work with existing radiators?
Yes, that can be possible. Demand, emitters and required water temperatures need to fit together. The business checks what can be retained or should change. Ruling out every radiator would be as wrong as automatically promising suitability.
Do I already need to know the heat-pump type?
No. You can initially request assessment of a suitable solution. The building, available sources, space and local conditions matter. A preference can be discussed but does not replace professional checks.
Can an existing ground probe be retained during replacement?
That can be possible but needs checking for the new demand and equipment. Existing documents help. The mere presence of a probe does not confirm suitability for every new capacity or additional cooling.
Can every heat pump also provide cooling?
No. Cooling depends on equipment, source, distribution and installation. Mention desired cooling from the start. Suitable temperatures and protection against moisture need professional consideration for water-based surfaces.
Are subsidies guaranteed in the quote?
No. The relevant programme, deadlines and conditions are checked for the project. Compare the price before expected support and clarify application preparation. Possible funding is not an automatic payment promise.
Is everything included in a heating-replacement price?
Only where the items are expressly agreed. Removal, tank disposal, electrics, distribution, approval documents and commissioning may be included differently. Compare the complete usable system.
