What to look for in a heat pump installer
- MCS certification (essential for grants) — Microgeneration Certification Scheme accreditation is mandatory if you want to claim the £7,500 Boiler Upgrade Scheme (BUS) grant. The installer's MCS number applies to the company, and the heat pump itself must also be MCS-listed. Without both, the grant is not available.
- F-gas qualification — Heat pumps contain refrigerant (typically R32 or R290). Anyone installing, servicing, or decommissioning the refrigerant circuit must hold an F-gas certificate (Category I for stationary equipment). Ask to see the certificate.
- Specific brand training — Mitsubishi, Daikin, Vaillant arotherm, Samsung EHS, and Grant Aerona each have manufacturer-specific commissioning procedures. A manufacturer-trained installer is more likely to set the system up correctly for your home and maintain warranty cover.
- Heat-loss survey using PAS 2035 / MIS 3005-D method — A proper heat-loss survey calculates room-by-room heat loss using building fabric data and design temperatures (typically -3°C external for southern England). Anyone who quotes a heat pump size without this survey is guessing — and an oversized unit short-cycles, while an undersized unit fails to heat the home in cold weather.
- Public liability insurance and BUS-approved status — Look for at least £5 million public liability cover. For BUS grant eligibility, the installer must be registered with the scheme and the work must be done to MIS 3005-D standards.
- Knowledge of radiator and emitter sizing — Heat pumps work best at lower flow temperatures (35–55°C) than gas boilers (65–80°C). This often requires upsized radiators or underfloor heating. A competent installer will assess your existing emitters and quote replacements where needed — not just slot in a heat pump and hope for the best.
Questions to ask before hiring
- Are you MCS certified, and is the heat pump model MCS-listed? Both must be true to claim the BUS grant. Ask for the MCS certificate number for the company and confirm the proposed heat pump appears on the MCS database (search by manufacturer and model).
- Will you carry out a full PAS 2035 heat-loss survey before quoting? A 30-minute walkthrough is not a heat-loss survey. A proper survey takes 1–2 hours and measures room dimensions, window types, insulation, and air-tightness. Any quote without this is unreliable.
- What size unit will you install, and what is the design flow temperature? Modern heat pumps should run at 45–50°C flow temperature for good efficiency. If the installer designs at 60°C+, your COP and running costs will suffer. Push back if they cannot explain the design choice.
- Will my radiators need upgrading, and what is the cost? Most homes need some radiator upgrades to run efficiently with a heat pump. The installer should provide a room-by-room schedule showing existing and proposed radiator sizes. Watch out for installers who say “the existing rads will be fine” without measuring.
- Can you handle the BUS grant application on my behalf? MCS-certified installers can submit the grant application directly. The grant is paid to the installer, who deducts it from your bill. Confirm this is included in the quote and ask whether they have applied successfully for similar properties.
- What is the warranty on the heat pump and on installation labour? Most reputable manufacturers offer 7–10 years on the heat pump itself (subject to annual service). Installer labour warranty is typically 2–5 years. Get both in writing.
Red flags to watch for
- Quotes a heat pump size without a heat-loss survey. Sizing a heat pump from rough estimates almost guarantees an oversized or undersized system. Both lead to high running costs and poor comfort. Walk away from any installer who skips the survey.
- Says “your existing radiators will be fine” without measuring. Most existing radiator setups will not deliver enough heat output at heat pump flow temperatures. Anyone who skips this assessment will install a system that under-performs in cold weather.
- Not MCS certified but offers to install anyway. You will lose the £7,500 BUS grant entitlement, and the installation will not meet MIS 3005-D standards. The short-term saving is far smaller than the lost grant.
- Recommends a high flow temperature design (60°C+). This means the installer is designing to your existing radiators rather than designing the system properly. The result is a heat pump running like an inefficient boiler — high bills with poor environmental benefit.
- Cannot explain refrigerant type and F-gas implications. R32 and R290 (propane) are the most common. R290 in particular requires specific safety competence. An installer who cannot explain refrigerant choice may not be properly trained.
- Pushes immediate decision without full design. A proper heat pump installation involves heat-loss survey, design, quote, and contract — typically 2–4 weeks. High-pressure sales tactics for same-day deposits are a warning sign of a low-quality operator.
What to expect on costs
Air-source heat pump installations in Kent typically run £9,000–£14,000 before grants. The Boiler Upgrade Scheme (BUS) grant of £7,500 is deducted by MCS-certified installers, bringing typical costs to £1,500–£6,500 for a full system on an existing home. Radiator upgrades often add £800–£2,500. Underfloor heating retrofits range from £3,000–£8,000 per floor. Annual service costs £120–£200 and is required to maintain manufacturer warranty.
For a detailed breakdown, see our full cost guide.
Find rated heat pump installers in Kent
- Heat Pump Installers in Kent — county-level directory
- Heat Pump Installers in Maidstone
- Heat Pump Installers in Canterbury
- Heat Pump Installers in Dartford
- Heat Pump Installers in Tunbridge Wells
- Heat Pump Installers in Ashford
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