UK Heat Pump Response installs MCS-certified air source heat pumps that deliver 3.5-4.5kW of heat per 1kW of electricity (350-450% efficiency vs gas boiler 92%). We survey property heat loss, calculate radiator sizing, apply for £7,500 Boiler Upgrade Scheme grant, install outdoor unit and buffer tank, upgrade radiators if needed—then commission system to Building Regs Part L compliance for £60-80/month running costs vs £140 gas.
Survey week 1. BUS grant approved week 3. Outdoor unit installed day 1. Pipework and tank day 2. Radiators upgraded days 3-4. Commissioned day 5.
Boiler Upgrade Scheme (BUS) grant: £7,500 off heat pump installation (deducted from invoice—you never pay it). MCS certification mandatory for grant eligibility. Typical 8kW system costs £10,500-13,000 installed = £3k-5.5k after grant. COP (Coefficient of Performance) 3.5-4.5 means system produces 3.5-4.5× heat output vs electrical input. Flow temperature 45-55°C (vs gas boilers 65-75°C)—requires larger radiators or underfloor heating. Building Regs Part L notification required (U-values, ventilation, controls). Running cost: 3-bed semi £900/year electricity vs £1,680/year gas boiler (at 26p/kWh electricity, 6p/kWh gas—heat pump still cheaper due to efficiency).
From heat loss survey to Building Regs compliance
Outdoor unit extracts heat from air down to -10°C, compresses refrigerant to raise temperature, transfers heat to central heating system. System components: outdoor unit (8-12kW typical for 3-bed house), indoor buffer tank (120-180L), controls (weather compensation + smart scheduling), circulation pump. Installation: outdoor unit on concrete plinth (600x600mm base, 1.5m from windows for noise compliance MCS020 standard), pipework buried/lagged to indoor tank, connect to heating system, wire electrics (32A supply required—consumer unit upgrade if only 60A main fuse). Cost: £10,500-13,000 installed before grant (8kW Daikin/Mitsubishi/Samsung unit). After £7,500 BUS grant: £3,000-5,500 out-of-pocket. Timeline: 4-5 days install (1 day outdoor/indoor units, 2 days pipework/tank, 1 day radiators, 1 day commission). Noise: 42-55dB at 1m (dishwasher volume—MCS requires <42dB at nearest neighbor's window, achieved via positioning/acoustic barriers if needed).
Boiler Upgrade Scheme (BUS) provides £7,500 grant toward air source heat pump (ASHP) installation to replace fossil fuel heating. Eligibility: England/Wales properties (Scotland has separate scheme), no existing heat pump, replacing gas/oil/LPG boiler or electric storage heaters, property EPC rated (doesn't matter what rating—just must have valid certificate), MCS-certified installer. We handle: full BUS application via Ofgem portal (TRN number obtained), submit property EPC, confirm system specs (8kW ASHP replacing gas boiler), liaise with Ofgem for approval (2-3 weeks), redeem voucher on completion (£7,500 deducted from your invoice—you pay remainder only). Important: installer must be BUS-registered with Ofgem (we are). Homeowner cannot apply directly—installer-led process. Grant limited availability (government budget £450M = 60,000 homes)—apply early before funding exhausted. One grant per property (cannot claim again for 7+ years). Landlord properties eligible (tenant or landlord can apply).
Critical first step: calculate property heat loss to size heat pump correctly. Survey measures: property dimensions (wall area, roof area, floor area, window area), construction type (solid wall/cavity/insulated, loft insulation depth, glazing type single/double/triple), ventilation (draughts, trickle vents, extractor fans), design outdoor temperature (-3°C for UK average). Calculation: heat loss per room at design temp (e.g., lounge 15m² with single glazing loses 2.1kW at -3°C outdoor/21°C indoor). Total house heat loss 6-10kW typical for 3-bed semi. Heat pump sized 10-15% above peak loss (8kW pump for 7kW heat loss—allows margin for coldest days + hot water reheat). Undersized pump = struggles below 0°C, backup immersion heater kicks in (expensive). Oversized pump = short-cycles (on-off frequently), wears compressor, poor efficiency. We use CIBSE heat loss calculation software (industry standard, Building Regs approved). Survey cost: £150-250 (refunded if proceeding with install). Takes 2-3 hours on-site, report delivered in 3-5 days with radiator sizing recommendations.
Heat pumps run at 45-55°C flow temperature (vs gas boilers 65-75°C)—cooler water requires larger radiators for same heat output. Survey identifies undersized radiators: lounge needs 2.1kW heat, existing radiator delivers 1.8kW at 50°C flow (adequate at 70°C with gas, inadequate at 50°C with heat pump). Solution: upsize radiator to 600x1400mm double-panel convector (delivers 2.4kW at 50°C). Typical upgrades: 3-5 radiators replaced (£120-180 each), 3-4 kept (already oversized or room less critical). Alternative: add second radiator in room (keep existing + add extra)—cheaper than replumbing if pipework awkward. Underfloor heating ideal for heat pumps (operates 35-40°C, large surface area)—worth considering for extensions/renovations. Pipework: heat pumps require buffer tank (stores hot water, prevents short-cycling, smooths demand). Install 120-180L tank near heat pump indoor unit, connect flow/return to existing heating system. May require 28mm pipework upgrades if existing 15mm (higher flow rates needed). Inhibitor flush essential—old sludge in system damages heat pump heat exchanger (Sentinel X800 flush + X100 inhibitor, costs £150-200, takes 4-6 hours).
Heat pumps heat water slower than gas boilers (combi boilers deliver 12-16L/min instant hot water, heat pumps need hot water cylinder preheated). Tank sizing: 180-250L for family (4 people), 120-150L for couple. Heating time: 180L tank from 10°C to 55°C = 2.5-3 hours with 8kW heat pump (vs 45 minutes with 24kW gas boiler). Solution: schedule hot water heating off-peak (Octopus Agile 2-5am at 7p/kWh) so tank ready for morning showers. Legionella protection: heat to 60°C weekly (kills bacteria)—heat pump alone struggles above 55°C, use immersion heater boost or hybrid cylinder with integrated backup element (auto-boost to 60°C weekly, then drop to 50°C daily). Cylinder types: (1) Direct unvented (heat pump only heats, no backup) = £800-1,200. (2) Indirect with immersion (heat pump primary, 3kW immersion backup for boost/legionella) = £1,000-1,500. (3) Thermal store (buffer tank + hot water coil integrated) = £1,500-2,200. We recommend indirect with immersion for reliability (heat pump does 95% of heating, immersion covers edge cases).
Heat pumps maximize efficiency when running continuously at low output (not on-off like gas boilers). Weather compensation achieves this: outdoor sensor measures temperature, controller adjusts flow temperature automatically (e.g., -3°C outdoor = 50°C flow, +10°C outdoor = 35°C flow). Eliminates thermostat on-off cycling, maintains constant comfort. Controls required: (1) Weather compensation controller (reads outdoor temp, modulates heat pump output). (2) Programmable schedule (reduce overnight when sleeping, boost morning). (3) Setback vs shutdown (setback = drop temp 2°C, maintain heat pump running; shutdown = off completely—setback better for efficiency, avoids heat pump working hard to catch up from cold). (4) Room-by-room control (TRVs on radiators, close bedrooms/guest rooms to avoid heating unused spaces). Smart options: Daikin Madoka (£250, WiFi app control, schedule per room), Samsung SmartThings (£200, integrates with Alexa/Google), Mitsubishi MELCloud (£150, remote monitoring). Worth it for: detailed energy monitoring (see exact kWh per day/week), fault alerts (low pressure/refrigerant leak warnings), optimized scheduling based on usage patterns. Running costs drop 10-15% with good controls vs poor on-off thermostat use.
£7,500 BUS grant makes heat pumps affordable
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