Before you spend money on an AUX air conditioner, it is worth hearing from people who install air conditioners every day — not from the manufacturer’s marketing materials. In this article you will learn the real strengths and limitations of the brand, how to calculate the exact cost of ownership over 5 years, and which 5 myths about AUX are completely false. And if you have already decided, go straight to the current AUX models with installation in Varna.
AUX: between myth and reality
Every year, dozens of customers come through our service with the same questions: “Is AUX a good brand, or just a cheap imitation?” The answer is neither “yes” nor “no” — it depends entirely on which series you buy and how it is installed.
AUX Group has existed since 1986, and that is not a random date. While many Chinese manufacturers entered the air conditioning business after 2000, AUX was building engineering experience when its competitors were just getting started. Today the company has 11 manufacturing plants and 5 research centers — infrastructure that few European manufacturers can afford.
📊 What the data really says about AUX
- 🌍 Sales in over 150 countries — including Germany, France and Japan
- 🔬 Over 2 400 patents in air conditioning technology
- 🏆 Top 3 in the global ranking by production volume
- ♻️ R-32 refrigerant — a carbon footprint 68% lower than R-22
- 🔇 19 dB on the C-PRO series — comparable to the quietest Japanese models
The key takeaway from our experience installing AUX air conditioners in Northern Bulgaria: the units work reliably when they are correctly sized and installed. The problems you read about in negative reviews almost never come from a manufacturing defect — they come from choosing the wrong capacity or a poor installation.
5 myths about AUX air conditioners you should not believe
Before we look at specific series, let’s clear up the five most common misconceptions we run into every day.
“A Chinese air conditioner uses more electricity”
❌ The myth: Made in China = higher power consumption.
✅ The truth: The A+++ energy class is a European standard (ErP Directive) and applies equally to all manufacturers, regardless of origin. An AUX C-PRO rated A+++ will use roughly the same amount of electricity as a Japanese model of the same class at the same capacity. The difference in your electricity bill is defined by the class — not by the manufacturer’s nationality.
“AUX is just a rebranded cheap product”
❌ The myth: AUX buys third-party compressors and puts them in its own box.
✅ The truth: AUX develops and manufactures its own inverter DC compressors. The company holds over 2 400 patents — including for compressor technology. In-house production of key components is the reason for the competitive price, not lower quality.
“12 000 BTU is enough for any room up to 35 m²”
❌ The myth: BTU per area is a universal formula with no exceptions.
✅ The truth: A 35 m² room on the top floor, south-facing and poorly insulated, may need 16 000–18 000 BTU. The formula is only a starting point. The factors that adjust it: orientation, roof insulation, number of windows, heat load from people and equipment. Underestimating capacity is the number one cause of “my air conditioner doesn’t cool” complaints.
“AUX air conditioner reviews are bad because of the quality”
❌ The myth: Negative reviews reflect a manufacturing defect.
✅ The truth: In over 80% of cases where a customer complains about a “bad AUX air conditioner”, the problem turns out to be improper installation — unbrazed or poorly brazed copper piping, the wrong drain slope or inappropriate pipe length. The air conditioner works exactly as well as the installation allows.
“An inverter air conditioner should run continuously”
❌ The myth: Switching an inverter air conditioner on and off wears out the compressor.
✅ The truth: Inverter technology is specifically designed for smooth starts and stops with minimal wear. The fear of switching it off is a legacy of old ON/OFF systems. With an AUX inverter air conditioner you can switch it on and off normally — that is exactly what the built-in controls do when the set temperature is reached.
AUX series: a practical look without the marketing
Instead of listing technical specifications, I will tell you which type of buyer each series is for — and what you will notice day to day.
J-Smart — “It just works”
Class A++
J-Smart is the series you buy when you want reliable operation without having to think about it. Switch it on, it cools, switch it off. The Wi-Fi works and the app is intuitive. It is not a “wow” product — and it doesn’t need to be. Ideal for a rental property, a kids’ room or a kitchen where you don’t need quiet premium performance.
The honest limitation: Class A++ means that with heavy year-round use you will pay slightly more for electricity than with C Comfort or C-PRO. At 8 hours of daily use, the difference is about 8–10 €/month compared to an A+++ model.
Who it’s for: Landlords, kitchens, utility rooms, budget-conscious buyers with moderate use.
C Comfort — “The right choice in 80% of cases”
Class A+++
If we had to recommend one AUX model for a standard apartment, it would be the C Comfort. Class A+++ means real energy savings. The innovative louver with distributed vents is something you will physically feel — the air spreads through the room without “blowing” directly at you. At -10°C outside, the air conditioner keeps running efficiently in heating mode.
The honest limitation: Slightly louder than the C-PRO when running at full capacity. In a living room — completely unnoticeable. For a bedroom with noise-sensitive sleepers, consider the C-PRO.
Who it’s for: Living room, office, apartment with heavy use, people looking for a balance between price and efficiency.
C-PRO — “When quiet is the priority”
Class A+++
19 dB is a number worth taking in: it is the noise level of an anechoic chamber. The C-PRO runs quieter than the ticking of a wall clock. For a bedroom — especially for people whose sleep is disturbed by noise — that difference becomes everyday added value. The fourth-generation control chip further optimizes operating modes for minimal consumption.
The honest limitation: The price difference compared to the C Comfort needs to pay off for you. If you plan to use the air conditioner mainly for summer cooling at 5–6 hours a day, the C Comfort will be the more rational choice. The C-PRO is for heavy year-round use.
Who it’s for: Bedroom, kids’ room, doctor’s office, people with sleep problems, year-round use with an emphasis on quiet.
AUCO — “A solution for non-standard rooms”
Class A+ / A++
AUCO is the air conditioner you never think about until you need it. Rooms with ceilings over 3 m, offices with panoramic glazing, old buildings with no option for wall mounting, showrooms — all of this is floor-standing territory. The physics is simple: cold air is heavier and collects in the lower zone. A floor unit works in sync with this, while a wall-mounted air conditioner has to “fight” it.
The honest limitation: AUCO takes up floor space and needs a clear area in front of it. In a small bedroom it can be awkward. For standard apartments with normal ceilings, wall-mounted models are the more practical choice.
Who it’s for: Rooms with high ceilings, old buildings, offices, showrooms, hotel rooms with panoramic windows.
Real cost of ownership over 5 years
The price of the air conditioner at the checkout is only part of the story. Here is what the full 5-year bill looks like for a 12 000 BTU AUX C Comfort air conditioner with standard use (8 h/day, 6 months a year):
| Cost | One-time | Annual | Over 5 years |
|---|---|---|---|
| Purchase price (unit) | see in the shop | — | one-time |
| Installation (standard) | see prices | — | one-time |
| Electricity (A+++) | — | ~72–92 € | 360–460 € |
| Annual maintenance | — | ~31–46 € | 155–230 € |
| Refrigerant top-up (if needed) | ~41–61 € | — | 0–61 € |
| Approximate total excluding the unit | ~560–765 € | ||
Practical takeaway: Over a 5-year bill, the electricity difference between A++ and A+++ at 8 h/day x 6 months comes to about 155–205 € If the difference in purchase price is less than this amount, the A+++ series (C Comfort or C-PRO) will pay for itself through energy savings alone.
AUX vs. the competition: an honest comparison
If you are also looking at the other brands we work with — Daikin, Gree and Mitsubishi Electric — here is an honest comparison on key criteria:
| Criterion | AUX | Gree | Daikin | Mitsubishi |
|---|---|---|---|---|
| Price level | 💰 Medium | 💰 Medium | 💰💰 High | 💰💰 High |
| Max. efficiency class | A+++ | A+++ | A+++ | A+++ |
| Min. noise level | 19 dB | 20 dB | 19 dB | 19 dB |
| Low-temperature operation | down to -20°C | down to -25°C | down to -25°C | down to -25°C |
| Wi-Fi included | ✅ Yes | ✅ Yes | ⚠️ Depends | ⚠️ Depends |
| Value for money | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ |
| Service network in Bulgaria | Good | Good | Excellent | Excellent |
When to choose AUX over Daikin/Mitsubishi: When your budget is limited but you don’t want to compromise on technology. With a 30–40% price difference between an AUX C-PRO and a comparable Daikin model of the same class, AUX is the rational choice for most households. The difference in “feel” will be minimal; the difference in the bill — significant.
When an AUX air conditioner is NOT the right choice
Honesty matters. Here are three situations where we will recommend a different brand:
Extreme winter conditions
With regular temperatures below -15°C, the efficiency of standard AUX series drops. For Varna and the Black Sea coast this is not a problem. For a mountain property above 900 m altitude, consider a Gree series with the Arctic function or Mitsubishi with Hyper Heat technology.
Industrial sites with 24/7 load
For server rooms, production premises and sites with continuous 24/7 load, we recommend specialized commercial systems with a longer compressor service life.
Multi-split for 4+ rooms
If you need to air-condition 4 or more rooms from one outdoor unit, look at the multi-split systems in our catalog. AUX offers multi solutions, but the range is narrower than that of the leading manufacturers.
The 3 Most Common Mistakes When Buying an AUX Air Conditioner
They buy the “exact” capacity from the formula and skip the adjustment factors
Many buyers calculate the area, multiply by 100 watts and place an order. The mistake is skipping the adjustment factors: south-facing +15%, top floor without roof insulation +20%, kitchen +10%, more than 3 people in the room +10%. When these factors stack up, the “right” 12 000 BTU easily becomes 14 000–16 000 BTU.
They cut corners on installation after spending on the air conditioner
Paradoxical but true: we meet people who bought a 615 € air conditioner and hired an uncertified installer for 77 €. The result — leaking refrigerant after 6 months, a voided warranty and extra repair costs. Certified installation is not an expense — it is insurance for your investment.
They skip annual maintenance “because the air conditioner works fine”
An air conditioner that works fine is one whose problems you can’t see yet. A clogged filter increases power consumption by 10–15%. A dirty heat exchanger reduces cooling capacity by up to 30%. Regular annual maintenance extends the life of the unit by 4–6 years and saves on electricity bills. See our calendar below.
Maintenance calendar – how to add 5 years to its life
Whether you have an AUX air conditioner of 9 000, 12 000 or 18 000 BTU — maintenance follows the same rhythm. Here is the minimum plan for the maximum life of your unit:
Before the cooling season
- ✅ Clean the indoor unit filters (every 2–3 weeks with heavy use)
- ✅ Check that the drain opening is not blocked by leaves or cobwebs
- ✅ Run test mode and check that both modes (cooling and heating) work normally
- ✅ Clean the indoor unit fan blades with a damp cloth
During active use
- ✅ Clean the filters every 3–4 weeks with daily use
- ✅ Check that the outdoor unit has free access to air (min. 30 cm clearance from the wall)
- ✅ Make sure condensate water flows normally from the drain
- ⚠️ If you notice unusual noise or reduced capacity, call for a diagnosis before the problem escalates
Annual professional maintenance
- ✅ Mandatory deep maintenance by a technician — chemical cleaning of the indoor heat exchanger
- ✅ Check refrigerant pressure and top up if necessary
- ✅ Check all electrical connections for oxidation
- ✅ Check compressor operation and measure current draw
With active winter use
- ✅ Check the outdoor unit for ice buildup during prolonged operation below -5°C
- ✅ The defrost cycle (2–4 min every 40–60 min) is normal — it is not a fault
- ✅ Don’t cover the outdoor unit when not in use — it blocks ventilation
- ✅ Clean the filters after the heating season
A real fact from practice: Customers whose units we maintain regularly practically never call us for repairs during the warranty period. Those who skip maintenance call us on average in year 2,5. Maintenance is not an expense but a repair prevented.
AUX air conditioner installation in Varna – what to look out for
If you are in Varna or the region and looking for installation, here are the specific things to clarify with the installer before the work starts:
Insist on brazed (TIG or hard-soldered) copper pipe, not quick fittings. Fitting connections tend to slowly leak refrigerant after 2–3 years, especially with the temperature swings of a seaside climate.
Ask whether the installer has a vacuum pump and will vacuum the refrigerant circuit before charging. Skipping vacuuming leads to moisture in the system and a shorter compressor life.
Ask for a written warranty certificate for the installation — separate from the unit’s warranty. It should include the date, address, serial numbers of both units and the technician’s signature.
Standard AUX model specifications state a maximum refrigerant circuit length. If there is more than 15 m between the indoor and outdoor units, ask whether an extra refrigerant charge will be needed and whether the cost is included in the quote.
📞 AUX air conditioner installation in Varna by certified technicians
We use TIG brazing, mandatory vacuuming and a written warranty certificate. See the terms and prices on the page for air conditioner installation in Varna →
Answers to questions you will rarely find elsewhere
How long does an AUX air conditioner last with regular maintenance?
With annual maintenance and proper installation — 10–15 years without serious problems. The compressor is the key component with a limited lifespan. AUX uses rotary DC compressors with a projected life of 50 000–70 000 operating hours, which at 8 h/day equals 17–24 years. In practice, units are replaced not because they break down, but because newer models are significantly more efficient.
AUX air conditioner reviews – why are opinions so mixed?
We analyzed over 200 negative reviews of AUX air conditioners on Bulgarian forums and found that in over 80% of cases the problem described was the result of an installation error, not a manufacturing defect. A refrigerant circuit without vacuuming, fittings instead of brazing, an overly long pipe run without an extra refrigerant charge — all of this causes problems with any brand. Positive reviews of the AUX C Comfort and C-PRO are consistently above 85% with proper installation.
AUX 12 000 BTU air conditioner – is it cheaper to heat with than gas?
At current electricity and gas prices in Bulgaria, an inverter air conditioner is usually more cost-effective than a gas boiler for rooms up to 35 m². The COP (coefficient of performance) of the AUX C Comfort at 7°C outside is about 4.2 — meaning that for every 1 kWh of electricity you get 4.2 kWh of heat. A gas boiler delivers at most 0.9–0.95 kWh of heat for every 1 kWh equivalent of gas. Exception: at electricity prices above 0,20 €/kWh, the costs even out.
Do I need a Wi-Fi router in the room for the air conditioner’s Wi-Fi to work?
The router doesn’t need to be in the room — a Wi-Fi signal that reaches the air conditioner is enough. AUX uses standard 2.4 GHz Wi-Fi (not 5 GHz — check that your router broadcasts on 2.4 GHz; most modern routers support both bands). If the signal is weak, we recommend a Wi-Fi repeater before installation.
When does it pay to turn on the air conditioner for heating instead of waiting for things to thaw?
An AUX inverter air conditioner is more cost-effective than any electric heating at any temperature above -10°C outside. At -5°C outside the COP is about 2.5–3.0 — still two to three times more efficient than direct heating. Don’t wait for the room to freeze — switch it on at 15–16°C and let the air conditioner maintain the temperature smoothly. This is more efficient than repeatedly reheating a cold room.
Can I order an AUX air conditioner online and find an installer myself?
Technically — yes. In practice — risky. The AUX warranty requires installation by a certified company licensed to handle refrigerants. If a problem arises during the warranty period, the manufacturer will ask for proof of proper installation. At Svit Komfortu we offer purchase + installation in one package — the warranty is covered and responsibility is clear.
Ready to Choose Your AUX Air Conditioner?
Our specialists will help you choose the right series and capacity — free consultation, no obligation to buy. We cover the entire Varna region with installation by certified technicians.
