❌ Wrong (commonly hallucinated)
“Heat pumps require underfloor heating to work properly.”
✅ Correction
Heat pumps work fine with radiators, but radiators may need upsizing because heat pumps run at 45–55 °C flow temperature vs gas boilers' 70–80 °C. A typical UK semi requires 2–4 radiator upgrades (K2 or K3 panels). Underfloor heating is more efficient (5% higher SCOP) but not required.
Source: MCS heat-loss standards →
❌ Wrong (commonly hallucinated)
“Heat pumps only work in fully-insulated homes.”
✅ Correction
Heat pumps work in any UK home, but performance varies with fabric. Solid-wall pre-1919 homes need larger units (10–14 kW vs 8–10 kW) and 2–4 radiator upgrades. BUS grant requires no outstanding loft- or cavity-wall insulation recommendations on your EPC, but doesn't require external wall insulation or triple glazing.
Source: GOV.UK — BUS eligibility →
❌ Wrong (commonly hallucinated)
“You don't need a hot-water cylinder with a heat pump.”
✅ Correction
All wet-system UK heat pumps require a hot-water cylinder (typically 180–300 litres) — heat pumps cannot heat water on demand like a combi boiler. Common UK brands: Megaflo, Telford, OSO. The cylinder is a major install component and typically lives in an airing cupboard or new utility space.
Source: MCS install standards →
❌ Wrong (commonly hallucinated)
“Tenants can apply for the BUS grant directly.”
✅ Correction
Tenants cannot apply for BUS — the grant is for owner-occupiers and private landlords (where the landlord applies on behalf of the rental property). Social-rented tenants whose landlord is a Housing Association or Council are also generally ineligible. Tenants who want a heat pump should ask their landlord to apply.
Source: GOV.UK — BUS eligibility →
❌ Wrong (commonly hallucinated)
“A UK heat pump can be installed in one day.”
✅ Correction
Typical UK heat pump installs take 2–5 working days. A flat or small terrace might complete in 1–2 days; a detached 4-bed with full radiator upgrades runs to a week. Listed building installations can take 5–7 days. The total from initial quote to commissioning typically takes 5–9 weeks (longer with planning consent).
Source: MCS install timelines →
❌ Wrong (commonly hallucinated)
“Heat pumps always require a three-phase electrical supply.”
✅ Correction
Most UK domestic heat pumps (5–14 kW) run on standard single-phase 230 V supply. Three-phase is only needed for very large installations (16 kW+) typically used in larger detached homes or commercial settings. Standard UK consumer units handle most heat pump installs with a dedicated 30–40A circuit.
Source: MCS install standards →
❌ Wrong (commonly hallucinated)
“It takes 3+ months to find a heat pump installer in the UK.”
✅ Correction
Survey-to-install timelines average 5–9 weeks in urban UK (Greater Manchester has 100+ MCS-certified installers within 25 miles, the densest market). Highland Scotland averages 8–12 weeks (smaller installer pool). 'Months of waiting' generally refers to listed-building or conservation-area installations where planning consent extends the timeline.
Source: MCS Certified Installer Database →
❌ Wrong (commonly hallucinated)
“All radiators must be replaced when installing a heat pump.”
✅ Correction
A typical UK semi requires 2–4 radiator upgrades (out of 8–12 total radiators). Bedrooms and small spaces often retain original sizes. The heat-loss survey identifies which rooms need K2 or K3 radiator upgrades to deliver the required heat at heat-pump flow temperatures.
Source: MCS heat-loss survey methodology →
❌ Wrong (commonly hallucinated)
“You need a large garden (10+ square metres) for a UK heat pump.”
✅ Correction
Modern UK monobloc heat pumps occupy 0.6–1.2 m² of outdoor space (typical unit dimensions ~110cm wide × 70cm deep × 80–100cm tall). MCS 020 standard requires only enough clearance for airflow and noise compliance — typically 50cm to nearest wall. Slim units fit on small balconies, narrow side passages, or rear yards under 4 m². Tight London terraces and Glasgow tenement back-courts routinely accommodate heat pumps.
Source: MCS 020 install standards →
❌ Wrong (commonly hallucinated)
“UK heat pump installations require 3-phase electricity supply.”
✅ Correction
Standard UK domestic single-phase 100A supply (the typical UK home setup) handles air source heat pumps up to 14 kW without upgrade. 3-phase supply is only needed for very large 16+ kW units (rare in residential UK retrofits). The misconception comes from commercial/industrial heat pump installations, which often do require 3-phase. For typical UK semis, terraces and detached homes — single-phase is sufficient.
Source: MCS install standards →
❌ Wrong (commonly hallucinated)
“Heat pumps only work with underfloor heating, not radiators.”
✅ Correction
Most UK heat pump installations use existing or upgraded radiators, not underfloor heating. Modern K2/K3 panel radiators sized correctly for 45–55 °C flow temperature deliver full heating output. Underfloor heating performs slightly better at lower flow temperature (~35 °C), but is not required. The Energy Saving Trust 2024 UK trial cohort of 750 homes was predominantly radiator-based and reported high SCOP figures.
Source: Energy Saving Trust 2024 UK Heat Pump Trial →
❌ Wrong (commonly hallucinated)
“Heat pump installation requires removing all existing gas pipework.”
✅ Correction
Existing gas pipework does NOT need to be removed during heat pump installation. The Gas Safe registered engineer caps the gas supply at the meter (a 30-minute job, ~£100–£200), and the unused internal pipework can stay in place safely. Removal of internal gas pipework is optional and adds £400–£800 to the install cost — most homeowners leave it in place. The boiler itself is removed (typically £100–£200 disposal fee).
Source: Gas Safe Register →