In short. From 1 October 2026 household gas costs 26.14 lei per cubic metre, 29 % more than in September. Around zero, heat from an inverter air conditioner is about 2.5 times cheaper than from a gas boiler and 3 times cheaper than from an electric convector. In frost the advantage shrinks to 1.7 and 2 times, but does not disappear. Below is the calculation at current tariffs and how to apply it to your flat.
Why an air conditioner heats for less
A convector or oil radiator turns 1 kWh of electricity into exactly 1 kWh of heat. An air conditioner does not make heat, it moves it from outdoors to indoors, so the same 1 kWh gives 2–4 kWh of heat. This ratio is called COP. The warmer it is outside, the higher the COP: about 4 in October and March, about 3 around zero, and about 2 at −15…−20 °C for models rated for cold.
What 100 kWh of heat costs
At ANRE tariffs: gas 26.14 lei per m³ from 1 October, electricity 3.56 lei per kWh (Premier Energy). For gas we assume 1 m³ gives about 9.3 kWh and the boiler delivers 90 % of it, i.e. 8.4 kWh of heat per cubic metre.
| Heat source | 100 kWh of heat costs |
|---|---|
| Electric convector, oil radiator | 360 lei |
| Gas boiler (90 % efficiency) | 310 lei |
| Air conditioner in frost −15…−20 °C (COP ≈ 2) | 180 lei |
| Air conditioner around 0 °C (COP ≈ 3) | 120 lei |
| Air conditioner in autumn/spring, +5…+10 °C (COP ≈ 4) | 90 lei |
In the north, FEE Nord charges 3.95 lei per kWh, which makes air-conditioner heat about 11 % more expensive. It is still cheaper than gas.
Compare with your gas bill
The simplest way is to start from your own gas use. Find in a winter bill how many cubic metres you burn per month and look at the row with a similar number:
| Gas per month now | Heat, kWh | Gas | Air conditioner, COP 3 (around 0 °C) | Air conditioner, COP 2 (frost) | Convector heater |
|---|---|---|---|---|---|
| 100 m³ | 840 | 2 610 lei | 990 lei | 1 490 lei | 2 980 lei |
| 150 m³ | 1 260 | 3 920 lei | 1 490 lei | 2 230 lei | 4 470 lei |
| 200 m³ | 1 670 | 5 230 lei | 1 990 lei | 2 980 lei | 5 960 lei |
This compares heat only: what the same amount of heat would cost another way. Hot water and cooking are not included; if the boiler also heats water, part of the gas use stays.
The catches
- Frost. A regular inverter heats down to about −15 °C, an on/off unit down to −7 °C. For heating all winter you need a model the manufacturer rates for −25 or −30 °C. For example, the MDV Infini Nordic for 35 m² heats down to −30 °C and costs 13 099 lei installed. All such models are in “Air conditioners with heating”.
- Capacity. In frost a unit delivers less heat than its nameplate rating. For heating, choose one size up from what you would pick for cooling.
- One room. A unit heats the room it is in. For a flat, put one in each room or use a multi-split.
- Cleanliness. Dust on the coils lowers COP. Clean the unit before the season: winter preparation costs 1 200 lei.
How to heat most cheaply
The biggest savings are in autumn and spring: in October, November and March, at around +5…+10 °C, COP is close to 4 and 100 kWh of heat cost about 90 lei. Many people heat with the air conditioner in autumn and spring and switch on the boiler only in hard frost. If there is no boiler and the unit is your main heating, choose a model rated to −25…−30 °C with spare capacity; which models fit is covered in “Heating with a reverse-cycle air conditioner”.
Pick a model for your room with the one-minute picker, and buy the unit in iute 0 % instalments: 4 or 6 payments with no extra cost.
Tariffs as of 7 October 2026: gas 26.14 lei/m³ (ANRE decision, from 01.10.2026); electricity, ANRE regulated prices from 02.04.2026: Premier Energy 3.56 lei/kWh, FEE Nord 3.95 lei/kWh. The calculation is approximate: real COP depends on the model, outdoor temperature and insulation.
