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Panasonic Aquarea vs LG Therma V: Which Air Source Heat Pump Is Better? (2026)

Quick Verdict

LG Therma V is the more efficient choice on its MCS-certified figures, with lower estimated running costs.

Side-by-Side Comparison

FeaturePanasonic AquareaLG Therma V
Installed price (before grant)Price on quotePrice on quote
After £7,500 grant (illustrative, England and Wales)Price on quotePrice on quote
SCOP at 35°C (MCS)4.715.33Higher
SCOP at 55°C (MCS)3.573.86Higher
Largest size12kW12kW
Standard warranty3 years3 years
Longest warranty (conditions apply)7 years7 years
Sound power (declared)53 dB(A)49 dB(A)Lower
Annual running cost (est., 45°C flow)~£635/yr~£575/yrLower
Refrigerant and max flowR290, up to 75°C flowR290, up to 75°C flow
CountryJapanSouth Korea
UK brandNoNo
Best forHomeowners who want a mainstream Japanese brand with R290 models, including a T-CAP unit that holds full output in cold weatherHomeowners who want a quiet R290 monobloc with strong cold-weather output from a major electronics brand

Specifications and pricing are indicative for the UK market as at June 2026. Post-grant figures illustrate the £7,500 Boiler Upgrade Scheme in England and Wales (Scotland uses the Home Energy Scotland grant and loan; Northern Ireland has no equivalent). Running costs assume ~10,000 kWh of heat a year at 26.32p/kWh (Ofgem cap average, October to December 2026; changes quarterly). Confirm current models and exact pricing with your MCS-certified installer.

Price Comparison

Panasonic Aquarea does not publish an installed price and no credible third-party figure exists, so we show none. For scale, the median Boiler Upgrade Scheme install cost £12,908 before the grant (DESNZ Boiler Upgrade Scheme median, April to June 2026). LG Therma V does not publish an installed price and no credible third-party figure exists, so we show none. For scale, the median Boiler Upgrade Scheme install cost £12,908 before the grant (DESNZ Boiler Upgrade Scheme median, April to June 2026). So this pair cannot be ranked on price. In England and Wales the £7,500 Boiler Upgrade Scheme grant comes off either quote equally, with 0% VAT until 31 March 2027; your MCS-certified installer claims the grant for you. Compare written quotes on the same basis: unit size, cylinder, radiator changes and warranty.

Efficiency Comparison

SCOP (seasonal coefficient of performance) is the key efficiency measure for a heating heat pump: the kilowatt-hours of heat you get per kilowatt-hour of electricity across a whole heating season. The figures here are MCS-certified, at 35°C flow (underfloor heating or large radiators) and 55°C (hotter radiators). Panasonic Aquarea is certified at 4.71 at 35°C and 3.57 at 55°C, while LG Therma V is certified at 5.33 and 3.86. On our estimates at a 45°C design flow temperature, the LG Therma V costs about £60 a year less to run at Ofgem cap electricity prices, or approximately £600 over ten years. Real-world efficiency depends heavily on system design and flow temperature, which is what the MCS heat loss survey is for.

Warranty Comparison

Panasonic Aquarea: Up to 7 years parts and labour when a Panasonic PRO Partner supplies and installs the system and submits the warranty extension online after commissioning. The 3-year standard term comes from Panasonic's 2017 scheme; no current Panasonic UK page states the base term. LG Therma V: LG UK's consumer warranty page lists Therma V at 3 years basic and 7 years extended, with the unit serviced 'biannually'. LG UK's business page lists 5 years extended but directs private homes to the consumer page. Neither page states what qualifies a home for the extended term. Workmanship cover for the installation itself comes separately from your installer and should be in writing.

Noise Comparison

Noise matters in UK homes because the outdoor unit often sits close to a neighbour's boundary or a bedroom window. The like-for-like figure is the maker's declared sound power: the noise the unit itself emits. Panasonic Aquarea: 53 dB(A). LG Therma V: 49 dB(A). On paper the LG Therma V is quieter by 4 dB(A). What a neighbour hears is much lower and falls with distance, and permitted development rules require the installation to meet the MCS noise standard at their window, so siting matters as much as the unit.

Cold-Weather and Retrofit Suitability

Two things decide how well a unit suits an older UK home: cold-weather output and flow temperature. Panasonic Aquarea uses R290 refrigerant (up to 75°C flow), while LG Therma V uses R290 (up to 75°C flow). Both reach 70°C or more, so both can work with existing radiators; the decision comes down to price, warranty and installer availability. Modern units hold useful output well below freezing. In the colder parts of the UK (Scotland and northern England in particular), frosty mornings trigger short defrost cycles that trim efficiency, so ask each installer for low-temperature output figures and take the MCS heat loss survey seriously; radiator upsizing is more commonly recommended there so the system can run at efficient flow temperatures.

Pros and Cons

Panasonic Aquarea

Pros

  • R290 refrigerant in both the L Series and T-CAP M Series
  • Water flow temperatures up to 75°C for radiator systems
  • T-CAP M Series 12 kW keeps its full 12 kW output at -7°C outdoor
  • Up to 7-year parts and labour warranty through Panasonic PRO Partner installers
  • Fitted by ScottishPower's installer Plug Me In; British Gas has a Panasonic service deal

Cons

  • The 7-year warranty only applies when a PRO Partner installer registers it
  • T-CAP M Series outdoor units are large and heavy: 1,520 mm tall and 161 kg
  • L Series 9 kW output falls to 7.0 kW at 2°C and -7°C outdoor (35°C flow)
  • No published installed price

LG Therma V

Pros

  • R290 refrigerant, rated A+++ at both 35°C and 55°C flow
  • Quiet Mark listed (9 kW and 12 kW), with 49 to 50 dB(A) declared sound power
  • Strong cold-weather output: 9.0 kW (9 kW model) and 11.8 kW (12 kW model) at -7°C
  • Up to 75°C flow and operation down to -28°C outdoor
  • Up to 7-year warranty for homes per LG UK's consumer warranty page, with servicing

Cons

  • Large and heavy: the 12 kW unit is 1,560 mm wide and weighs 181 kg
  • LG UK's warranty pages do not say what qualifies for the extended term
  • Standard warranty is 3 years, and LG requires servicing 'biannually'
  • No published installed price

Which Should You Choose?

Choose Panasonic Aquarea if...

  • Homeowners who want a mainstream Japanese brand with R290 models, including a T-CAP unit that holds full output in cold weather

Choose LG Therma V if...

  • You want the higher certified efficiency (SCOP 5.33 vs 4.71 at 35°C, MCS)
  • A lower declared sound power matters to you (49 vs 53 dB(A))
  • You want lower estimated annual running costs (~£575/yr vs ~£635/yr)

The grant is the same, whichever brand you pick

Every air-to-water unit on this page qualifies for the £7,500 Boiler Upgrade Scheme grant in England and Wales (£9,000 for oil and LPG heated homes until March 2027) when fitted by an MCS-certified installer, who claims it on your behalf so it comes straight off the quote. Scotland uses the Home Energy Scotland grant of up to £7,500 (£9,000 rural and island) plus an optional interest-free loan; Northern Ireland currently has no equivalent scheme. 0% VAT on residential installations applies UK-wide until 31 March 2027. Accurate as at July 2026.

Boiler Upgrade Scheme guide →Gas boiler vs heat pump calculator →

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