Heat Pump COP & EER Explained: How to Read an Aircon Spec Sheet
The honest answer: most aircon buyers look at the kW capacity and the star rating, and stop there. That’s enough to avoid disasters but not enough to actually pick the right heat pump for an Adelaide household. The spec-sheet numbers that matter are COP, EER, the rated-vs-real-world capacity gap, the cold-ambient performance line, and the SEER/SCOP seasonal averages. Once you can read these five fields, you’ll spot the difference between a $3,000 and a $4,500 system that look identical at first glance — and you’ll know which one is actually going to deliver in a 41°C summer or a -2°C Hills winter.
This guide walks through what each spec-sheet number means, why the marketing star rating is only half the story, and the five figures any Adelaide buyer should write down before they sign on a heat pump installation.
The numbers that matter on an aircon spec sheet (and the marketing fluff)
A typical residential aircon spec sheet has 30+ numbers on it. Most are noise. Five matter:
One — rated cooling capacity (kW) at 27°C indoor / 35°C outdoor. The headline cooling number. Most marketing. Two — rated heating capacity (kW) at 20°C indoor / 7°C outdoor. The headline heating number. Three — EER (cooling) and COP (heating). Efficiency at rated conditions. Four — capacity at 0°C ambient (heating). What the unit actually delivers on a Hills winter morning. Five — SCOP (Seasonal COP) and SEER (Seasonal EER). Real-world averages across the season.
Marketing fluff to ignore: “ECO mode efficiency”, “Boost mode capacity” (transient peaks, not sustainable), star rating (decent first filter but obscures detail), “energy savings of up to X%” without baseline, “Wi-Fi enabled” (you should expect this in 2026, it’s not a feature anymore).
The Energy Rating Australia ZERL technical guide is the authoritative reference for the standard test conditions that produce the rated numbers. Worth a read once if you’re comparing premium options.
COP (Coefficient of Performance) — kW out per kW in, explained
COP is the heat-pump efficiency in heating mode. COP = heat output (kW) divided by electrical input (kW).
A COP of 4.0 means the unit produces 4 kW of heating from 1 kW of electrical input. That’s heat-pump magic — you’re moving 3 kW of heat from outside (where it’s cold) into your home (where it’s warm), and only paying for 1 kW of electricity to do the moving.
Why heat pumps beat resistive heaters. A resistive heater (panel heater, radiant bar, ducted gas-electric coil) has a COP of exactly 1.0 — every kW of electricity becomes 1 kW of heat. A heat pump at COP 4.0 delivers four times the heat for the same power. That’s why a 7kW heat pump uses about 1.7 kW of electricity to heat your house, while a 7kW resistive heater would use 7 kW.
Typical COP numbers (heating mode, rated conditions):
| Tier | Heating COP at +7°C |
|---|---|
| Budget split | 3.2–3.6 |
| Mid-range split (Daikin Lite, Mitsubishi MSZ-AP, Fujitsu Lifestyle) | 3.8–4.2 |
| Premium split (Daikin Cora, Mitsubishi MSZ-FH) | 4.2–4.8 |
| Top-tier (Daikin Ururu Sarara, Mitsubishi Hyper Heating) | 4.6–5.2 |
| Premium ducted (Daikin Premium Inverter, Mitsubishi Bronte) | 4.4–4.8 |
| Cold-climate ducted | 4.6–5.0 |
The number at the rated condition (+7°C ambient) is one data point. The number at lower ambient is more important — see “Adelaide Hills 0°C ambient” below.
EER (Energy Efficiency Ratio) — same idea, cooling-only side
EER is the cooling-mode equivalent of COP. EER = cooling output (kW) divided by electrical input (kW).
An EER of 3.5 means the unit delivers 3.5 kW of cooling per kW of electricity. Same heat-pump logic, working the other direction — moving heat out of the house instead of into it.
Typical EER numbers (cooling mode, rated 35°C ambient):
| Tier | Cooling EER |
|---|---|
| Budget split | 3.0–3.4 |
| Mid-range split | 3.6–4.0 |
| Premium split | 4.0–4.6 |
| Top-tier | 4.4–5.2 |
| Premium ducted | 3.8–4.4 |
EER vs COP — the asymmetry. Cooling EER is usually lower than heating COP for the same unit. The reason is the way the heat-pump cycle handles the temperature differential. In cooling, the unit is moving heat from a relatively cool room (24°C) to a hot ambient (35°C); the temperature lift is 11°C. In heating, the unit is moving heat from a cool ambient (7°C) to a warm room (20°C); the temperature lift is 13°C — but the absolute temperatures are lower, which actually favours the heat pump cycle. The thermodynamics give a slight COP advantage to heating-mode operation at moderate ambient.
This is why, for example, a Daikin Cora 5kW might be EER 3.8 cooling and COP 4.2 heating at rated.
SCOP and SEER — seasonal averages that beat single-point numbers
The shortcoming of EER and COP: they’re measured at one specific test condition. Real-world use covers a range of ambient temperatures and load levels.
SEER (Seasonal Energy Efficiency Ratio) — cooling-side seasonal average. Tested across four ambient conditions (typically 20°C, 25°C, 30°C, 35°C) and weighted by typical seasonal hours-distribution.
SCOP (Seasonal COP) — heating-side seasonal average. Tested across multiple ambient conditions including cold ambient.
For Adelaide:
- A unit with EER 4.0 cooling at rated typically has SEER 3.6–3.8.
- A unit with COP 4.4 heating at rated typically has SCOP 3.8–4.2.
The difference between EER/COP and SEER/SCOP captures the part-load and varied-condition reality. A unit that holds its efficiency well across the seasonal range has a smaller gap; a unit that only performs at the rated point has a bigger gap.
The buyer’s question: ask for both numbers. If the spec sheet only shows EER without SEER, push back — the seasonal number tells the more honest story.
Why “rated capacity” and “real-world capacity” can differ by 30%
The “rated cooling capacity” is measured at 27°C indoor / 35°C outdoor. The “rated heating capacity” is measured at 20°C indoor / 7°C outdoor. These are mild conditions designed for fair brand-to-brand comparison.
Real-world capacity drops below the rating in three scenarios:
One — extreme ambient. A 7kW rated split in cooling delivers about 7 kW at 35°C ambient. At 41°C ambient (Adelaide summer worst-case), the same unit delivers about 5.5–6 kW. That 15–20% capacity loss is why properly-sized Adelaide systems include a 10–15% headroom margin against rated.
Two — extreme indoor load. Hot day, full sun on the windows, 8 people in the room — the heat load is way above the rated 27°C indoor design point. The unit reaches its rated capacity but the room load exceeds it.
Three — long line-set runs. Refrigerant pipe runs over 8m introduce capacity loss (refrigerant pressure drop, heat gain on the line). Spec sheets usually show capacity at “5m line-set”; longer runs in real installs lose 3–5% per additional 5m.
The rule for Adelaide: size for 1.10–1.15× the calculated room load at the unit’s rated capacity. Don’t size for 1.0× — you’ll be running at 100% on every hot day. The detailed method is covered in our aircon sizing guide.
Adelaide Hills 0°C ambient — the spec line that matters most for heating
The single most important spec-sheet line for an Adelaide Hills heat pump installation is the heating capacity at low ambient. Different brands publish it differently:
- Daikin — “Heating capacity at 2°C ambient” and “Heating capacity at -7°C ambient” (Premium Inverter and Cold Climate models)
- Mitsubishi Electric — “Hyper Heating maintained capacity at -15°C” (FH series)
- Fujitsu — “Cold-climate operation capacity at -10°C” (Lifestyle Cold-Climate variants)
At 0°C ambient, a standard mid-range split typically delivers 60–70% of its rated heating capacity. A cold-climate-rated unit delivers 90–100% of rated capacity at the same ambient.
The numerical example: a 7kW rated standard MSZ-AP delivers about 4.5 kW at 0°C ambient. The same physical kW MSZ-FH (Hyper Heating) delivers 6.8 kW at 0°C and 6.4 kW at -10°C. On a Stirling, Aldgate or Mt Barker home running 600+ heating-hours per year, the difference is decisive.
For metro Adelaide where overnight winter lows rarely drop below 4°C, the cold-climate spec is overkill. For Hills installs, it’s the spec that separates the right pick from the wrong pick.
Worked example: comparing a Daikin Alira X vs a Mitsubishi Bronte spec sheet
Two real 7kW residential units, side-by-side:
| Spec | Daikin Alira X DX31U | Mitsubishi MSZ-FH71 (Hyper Heating) |
|---|---|---|
| Cooling capacity (rated 35°C) | 7.1 kW | 7.1 kW |
| Cooling capacity range | 1.4–8.5 kW | 1.6–8.7 kW |
| Cooling EER | 4.0 | 3.8 |
| SEER | 3.7 | 3.6 |
| Heating capacity (rated 7°C) | 8.0 kW | 8.0 kW |
| Heating capacity at 0°C | 6.4 kW | 7.8 kW |
| Heating capacity at -7°C | 5.2 kW | 7.2 kW |
| Heating COP (rated 7°C) | 4.6 | 4.5 |
| SCOP | 4.0 | 4.2 |
| Indoor sound (low) | 19 dBA | 21 dBA |
| Outdoor sound | 48 dBA | 50 dBA |
| Star rating (cooling/heating) | 4.5 / 4.5 | 4.5 / 5.0 |
| Refrigerant | R32, 1.15 kg | R32, 1.30 kg |
| Adelaide fitted price | $3,400 | $3,800 |
Reading the numbers:
The Daikin wins on cooling efficiency (EER 4.0 vs 3.8) and indoor sound (19 dBA vs 21 dBA). The Mitsubishi wins decisively on cold-ambient heating — 7.8 kW vs 6.4 kW at 0°C, and 7.2 kW vs 5.2 kW at -7°C. SCOP favours Mitsubishi (4.2 vs 4.0) because the seasonal average includes those cold days where it dominates.
The recommendation depends on location:
- Metro Adelaide (Burnside, Norwood, Glenelg): Daikin Alira X. Slightly better cooling, quieter, $400 cheaper, and the Hills cold-ambient advantage doesn’t apply.
- Adelaide Hills (Mount Barker, Stirling, Aldgate): Mitsubishi MSZ-FH. The 1.4 kW cold-ambient advantage is the difference between cosy and uncomfortable on a 0°C morning.
This is exactly the kind of detail that’s invisible from the star rating alone. Both units rate 4.5 stars. The actual fit-for-purpose depends on the ambient profile of where the unit will operate.
The five spec-sheet numbers to write down before you buy
When you’re comparing more than one quote, write these five numbers in a row for each unit:
- Cooling capacity at rated (27°C indoor / 35°C outdoor): the headline kW.
- Heating capacity at 0°C ambient: the cold-morning reality. Critical for Hills installs.
- Cooling EER and Heating COP: the efficiency. Aim for EER 4.0+ and COP 4.5+ on premium tier.
- SEER and SCOP: the seasonal average efficiency. Closer to real-world bills than the rated point.
- Refrigerant type and charge weight: should be R32 in 2026, with a stated charge in kg. See our R32 vs R410A article for the detail.
A quote that doesn’t reference these five numbers is incomplete. Push the installer for the data sheets — they’re freely published on every manufacturer’s website.
The same five-number discipline applies whether you’re buying a single split or a whole-house ducted system. And it ties back to the inverter vs non-inverter and MEPS energy ratings decisions — different facets of the same engineering picture.
The AIRAH Application Manual on heat pumps is the technical handbook installers reference, and Energy Rating Australia maintains the model-by-model database for cross-checking.
When to call us
If you’re sitting on more than one quote and they’re showing different brands at apparently similar specs, submit them via the quote form and we’ll get back to you with full spec-sheet data alongside the price. That’s typically all it takes to surface which option is genuinely the right call for your house.
Frequently asked questions
What’s a good COP number for an Adelaide heat pump? For metro Adelaide, look for cooling COP above 4.0 and heating COP above 4.5 at rated conditions. For Adelaide Hills cold-climate use, push for heating COP above 3.5 at 0°C ambient — the cold-rated number that actually matters in winter. Premium heat pumps hit 5.0+ on cooling and 4.8+ on heating at rated conditions.
Why does my aircon’s COP drop on a cold morning? Heat pumps lose efficiency as the outdoor ambient drops because there’s less heat available in the cold air to extract. A unit rated COP 4.5 at +7°C might deliver COP 3.2 at 0°C and COP 2.4 at -5°C. Cold-climate heat pumps are engineered to hold COP 3.5+ down to -10°C.
Is COP measured in cooling or heating mode? Both — but they’re different numbers. EER (Energy Efficiency Ratio) is the cooling-mode efficiency. COP (Coefficient of Performance) usually refers to the heating-mode efficiency. Some manufacturers print both as COP-cooling and COP-heating to avoid the term confusion.
What’s the difference between EER and SEER? EER is the efficiency at one specific test condition (35°C ambient, full load). SEER is the seasonal average efficiency across multiple test conditions and load levels — closer to real-world use. SEER is always slightly lower than EER for the same unit because it includes part-load and varied conditions.
Why does the spec sheet show two capacity numbers? The ‘rated capacity’ is the unit’s nominal kW at standardised test conditions (27°C indoor, 35°C outdoor for cooling). The ‘minimum to maximum’ range shows the full operating range of the inverter — useful because it tells you what the unit can do at part-load and at extreme ambient.
Should I just trust the star rating instead of reading specs? The star rating is a useful first filter but it averages cooling and heating performance. For detailed comparisons, especially for Adelaide Hills cold-climate or whole-house ducted choices, the underlying COP/EER numbers tell a more complete story. Star rating + COP at 0°C ambient is the better combination.
Ready for a written quote with full spec-sheet data?
Submit the quote form — we’re ARC-licensed and happy to provide full manufacturer spec data alongside the install quote. Fast turnaround, no obligation.