Planning the Next 20 Years of Your Home Heating
A straightforward guide from Thermal Earth — specialists in ground and air source heat pumps across Wales and South West England for over 20 years.
Why are homeowners making the switch now?
Escape fuel price volatility
Gas rose 40% in a single year. Oil delivery prices follow global markets you cannot control. A heat pump runs on electricity — and as the grid gets greener, your heating gets cleaner without you doing anything.
The right choice for now and the future
The system you install today will still be running in 20–25 years. Heat pumps are the technology governments, grid operators, and building regulations are built around. Future-proofing is not a marketing phrase — it is engineering reality.
Up to £7,500 available now
The Boiler Upgrade Scheme provides £7,500 towards a ground source heat pump and £7,500 towards an air source heat pump. This grant is government-funded and subject to future policy review. It exists now.
How a heat pump actually works
A heat pump does not generate heat — it moves it. Just as a fridge moves heat out of its interior, a heat pump moves heat from outside your home (from the ground, air, or water) into your heating system. Because it is moving heat rather than burning fuel to create it, it delivers significantly more energy than it consumes. A well-designed system typically achieves a Coefficient of Performance (COP) of 3.0 to 5.0 — meaning for every unit of electricity used, three to five units of heat are delivered.
Does it work in winter?
Yes. Air source heat pumps are designed to operate effectively down to -20°C. Ground source heat pumps draw from ground temperatures that remain stable at 10–13°C year-round, regardless of air temperature. The key is correct sizing. A system designed properly for your property will perform reliably throughout a British winter.
Ground source or air source — which is right for your home?
| Ground Source | Air Source | |
|---|---|---|
| Heat source | Ground loop (borehole or horizontal trench) | Outdoor air |
| Typical COP | 3.5–5.0 | 2.5–3.5 |
| Garden space required | Yes (borehole: small; horizontal: large) | No (unit sits outside) |
| Noise | Silent — indoors | Low hum outdoors |
| Installation cost | Higher | Lower |
| Running cost | Lower long-term | Slightly higher |
| BUS grant | £7,500 | £7,500 |
| Best for | Off-gas, larger properties, long-term optimisation | Urban, smaller plots, retrofit |
Our consultants will assess your property, soil conditions, energy demand and budget before recommending a system. We do not push one technology over the other — we design what works.
What does installation involve?
1. Home survey (1–2 hours)
A Thermal Earth consultant visits to assess your property: insulation levels, radiator sizes, hot water demand, garden access and ground conditions. No obligation, no pressure. This is an information gathering exercise for both sides.
2. System design (1–2 weeks)
We prepare a full heat loss calculation for your property and design a system sized correctly for your actual demand — not a generic estimate. You receive a detailed proposal with projected running costs modelled conservatively.
3. Ground works (1–5 days depending on system)
For ground source systems, a borehole team drills to depth (typically 80–150m) or lays horizontal ground loops in your garden. For air source, the outdoor unit is positioned and secured. Our teams work tidily and to a clear schedule.
4. Internal installation (3–7 days)
The heat pump unit is installed, pipework connected, controls commissioned and the system tested. We co-ordinate the full project so you deal with one team, not multiple contractors.
5. Handover and aftercare
We walk you through the system, set your controls correctly and provide full documentation. Thermal Earth offers ongoing service and maintenance contracts to ensure long-term performance.
The honest cost picture
Installation costs (2026)
Ground source heat pump systems typically cost £15,000–£25,000 installed, before the £7,500 BUS grant. Air source heat pump systems typically cost £8,000–£14,000 installed, before the £7,500 BUS grant. These figures depend on property size, ground conditions, existing distribution system and hot water requirements. We do not provide generic quotes — every proposal is calculated from a site survey.
Running costs
Running costs depend on the COP of your system, your electricity tariff, your property’s heat demand and how well the system is designed. We model all of these for your property specifically. We do not use inflated projections. A typical well-insulated 4-bedroom property switching from oil to ground source heat pump can expect annual running cost savings of £400–£900, with full payback on the premium above a boiler replacement typically achieved within 7–12 years — improving as electricity costs fall relative to fossil fuels.
Available funding
- Boiler Upgrade Scheme (BUS): £7,500 for ground source or air source heat pumps. Applied for by your installer at point of installation. Available now.
- ECO4 scheme: For eligible low-income households. Ask us if you may qualify.
- Wales Warm Homes: Welsh Government warm homes programmes may offer additional support for eligible properties.
- Finance: Thermal Earth offers finance options to spread installation costs over monthly payments.
How to choose the right heat pump installer
The quality of design and installation determines the performance of your system over its lifetime. This matters more than the price of the equipment.
Questions to ask any installer
- Are you MCS certified? (Required to access BUS grant funding)
- Do you carry out a full heat loss calculation before designing the system?
- Will you size the system to my property or use a standard package?
- Do you design and install yourselves, or subcontract?
- What aftercare and service options do you provide?
- Can I speak to previous customers?
Red flags
- Quick quote without a site visit
- No mention of heat loss calculation
- Pressure to sign quickly
- No MCS certification
- No clear aftercare plan
Why Thermal Earth
Over 20 years of heat pump installations
We have been installing heat pump systems since before they became a government priority. Our experience is in the ground — literally — across hundreds of homes and commercial buildings across Wales and the South West.
Exclusive MasterTherm distributor
We are the exclusive UK distributor for MasterTherm heat pumps — Czech-manufactured systems built for Northern European climates, with R290 natural refrigerant and COPs up to 5.0. We know the equipment we sell from the inside out.
MCS certified, design-led
Every system is designed by our engineers from a full heat loss calculation. MCS certification is required for BUS grant access. We handle the grant application as part of your installation.
Structured aftercare
We offer service and maintenance contracts to keep your system performing at design efficiency over its lifetime. Our Comfort Care plan covers annual servicing, priority callout and parts.
Ready to find out what is right for your home?
Start with a no-obligation home survey. One of our consultants will visit, assess your property honestly, and give you a clear picture of what a heat pump system would look like — and cost — for your home.