Calculate your AC cost
AC Running Cost Calculator
Estimate your air conditioner's electricity cost
Estimated monthly running cost
₹2,434.16
≈ ₹29,615.62/year · 249.66 units/month
Switching to 5-star saves ₹7,246.38/year
- Input power
- 1.49 kW
- ISEER
- 3.55
- Units per day
- 8.32
- Billed at (top slab)
- ₹9.75/unit
Assumes a 70% compressor duty factor and ISEER 3.55 for a 3-star unit. Priced at your top electricity slab (₹9.75/unit incl. FCA & duty).
Efficient models that cut this cost
A higher star rating pays for itself in a few seasons. Sample picks (indicative pricing):
1.5 Ton 3 Star Inverter Split AC
₹34,990.00
View on AmazonAffiliate link · disclosure
1.5 Ton 5 Star Inverter Split AC
₹44,990.00
View on AmazonAffiliate link · disclosure
1 Ton 5 Star Inverter Split AC
₹38,990.00
View on AmazonAffiliate link · disclosure
Why most AC bill calculators get this wrong
SEER vs ISEER
Some calculators quietly borrow US SEER-based efficiency assumptions instead of BEE's India-specific ISEER standard. The two are tested against different climate and duty-cycle conditions, so a SEER-based estimate doesn't reflect how an Indian-labelled AC actually performs here.
Flat-rate vs top-slab billing
Many tools price every unit at one flat, national-average rate. Indian tariffs are telescopic — an AC adds to your existing usage, so its units land on your highest slab, which is almost always well above the average rate quoted.
Keeping pace with BEE's ISEER rebalancing
BEE periodically revises the ISEER thresholds behind each star rating, so a fixed set of efficiency numbers can quietly go stale. We keep our ISEER table current with BEE's latest published bands rather than reusing figures from years ago — always check the current BEE label on a specific model, since exact threshold dates and revision details vary by product category and are set directly by BEE.
The ISEER formula behind this calculator
The formula, in full
Input kW = (Tonnage × 3.517) ÷ ISEER
Daily units = Input kW × Daily hours × 0.7 (duty factor)
Cost = Daily units × your DISCOM's top-slab rate (+ FCA + duty)
3.517 kW/ton is the standard refrigeration-ton conversion. The 70% duty factor accounts for the compressor cycling on and off rather than running flat out for every minute it's switched on. ISEER (Indian Seasonal Energy Efficiency Ratio) is BEE's efficiency metric — the higher it is, the less electrical input the same cooling output needs:
1★
ISEER 3.1
2★
ISEER 3.3
3★
ISEER 3.55
4★
ISEER 4.1
5★
ISEER 4.7
These are the exact constants and formula our calculator uses — not a simplified restatement.
How slab-wise billing changes your AC cost
The exact same 1.5 ton, 3-star AC running 8 hours/day — priced at each state's real top-slab tariff, computed live by this calculator's own engine:
| DISCOM | ₹/unit (top slab) | Monthly cost | Annual cost |
|---|---|---|---|
| Maharashtra (MSEDCL) | ₹11.09 | ₹2,768.70 | ₹33,685.87 |
| Karnataka (BESCOM) | ₹8.96 | ₹2,236.93 | ₹27,215.99 |
| Delhi (BRPL) | ₹8.00 | ₹1,997.26 | ₹24,299.99 |
| Uttar Pradesh (UPPCL) | ₹7.51 | ₹1,874.93 | ₹22,811.62 |
| Tamil Nadu (TNEB) | ₹6.75 | ₹1,685.19 | ₹20,503.12 |
Why your AC bill might be higher than your neighbor's
Dirty filters or coils
A clogged filter or dusty condenser coil restricts airflow, forcing the compressor to run longer for the same cooling — get it serviced before every summer.
Wrong fan speed or temperature setting
Running at the lowest temperature setting or a low fan speed makes the compressor work harder and cycle less efficiently than a moderate 24–26°C setting on auto fan.
Poor room insulation
Unsealed gaps, single-glazed windows, or a west-facing room with no shading let heat back in constantly, so the AC never gets to idle.
An older or degraded compressor
Compressor efficiency drops with age and wear — a 6-8 year old unit can use noticeably more power than its original ISEER rating implied when new.
Wrong tonnage for the room
An undersized AC runs constantly at full load; check whether yours is actually sized correctly with our tonnage calculator.
A different — or higher — tariff slab than your neighbor
Even identical usage can cost differently: Indian tariffs are telescopic, so if your base household consumption is already higher than your neighbor's, your AC's units land on a steeper slab than theirs. This is the one cause a DISCOM-aware calculator can actually show you — compare your state's slabs on our electricity bill calculators.
AC electricity consumption — quick reference table
| Tonnage | 3★ (units/hr — ₹/month, 8h/day) | 4★ (units/hr — ₹/month, 8h/day) | 5★ (units/hr — ₹/month, 8h/day) |
|---|---|---|---|
| 0.8 Ton | 0.55 — ₹899.00 | 0.48 — ₹778.00 | 0.42 — ₹679.00 |
| 1 Ton | 0.69 — ₹1,123.00 | 0.60 — ₹973.00 | 0.52 — ₹849.00 |
| 1.5 Ton | 1.04 — ₹1,685.00 | 0.90 — ₹1,459.00 | 0.79 — ₹1,273.00 |
| 2 Ton | 1.39 — ₹2,247.00 | 1.20 — ₹1,946.00 | 1.05 — ₹1,697.00 |
Approximate figures at Tamil Nadu (TNEB)'s top-slab rate (₹6.75/unit) and 8 hours/day usage, for quick browsing only. Use the calculator above for your own DISCOM and hours.
Real-world scenario: non-inverter 3★ vs inverter 5★
3-star, fixed-speed (non-inverter)
₹1,685.19/mo
₹20,503.12/year · 1.5T at 8h/day
5-star inverter
₹1,272.85/mo
₹15,486.40/year · 1.5T at 8h/day
That's ₹5,016.72/year less for the inverter unit in Tamil Nadu (TNEB). At an indicative ₹10,000.00 price premium, the 5-star pays for itself in about 2.0 years on running cost alone.
Our engine prices efficiency via ISEER (star rating), not inverter technology directly — but in today's BEE-labelled Indian market, 3-star split ACs are typically fixed-speed while 5-star models are almost always inverter units, so the star-rating comparison closely tracks the inverter-vs-non-inverter question in practice.
Simple ways to cut your AC bill
- 1Set the thermostat to 24–26°C rather than the coldest setting — each degree lower adds meaningfully to compressor runtime.
- 2Use the "auto" fan mode instead of forcing the lowest fan speed, which makes the compressor work harder for the same cooling.
- 3Get filters and coils cleaned every season — restricted airflow is one of the most common hidden causes of a rising bill.
- 4Seal window and door gaps and use curtains on sun-facing windows to cut the heat load the AC has to fight.
- 5Use a ceiling fan alongside the AC — it lets you raise the thermostat a degree or two without losing comfort.
- 6If you're buying new, choose a correctly-sized 5-star inverter model rather than an oversized unit — check our tonnage calculator first.
How AC running cost is calculated
Efficiency (ISEER). A star rating maps to an ISEER value — the higher it is, the fewer units the same cooling needs. We convert tonnage to cooling power, divide by ISEER for electrical input, and apply a compressor duty factor — see the exact formula and constants above.
Priced at your top slab. Since an AC adds to your existing consumption, its units fall in your highest tariff slab. We use that marginal rate (plus fuel cost adjustment and electricity duty) — so the estimate reflects what the AC really adds to your bill.
Related calculators
AC tonnage calculator
Not sure this is even the right AC size for your room? Check first.
3★ vs 5★ savings
See exactly how much a higher star rating would cut this cost.
Circuit safety calculator
Buying new? Check the MCB and wiring it needs too.
Offset it with solar
See the payback on a rooftop system sized for AC-heavy usage.
Frequently asked questions
How accurate is this AC running cost estimate?
It uses your AC’s ISEER-based efficiency, a ~70% compressor duty factor, and your DISCOM’s real top-slab tariff — a close planning estimate, not a billing-grade figure. Actual usage varies with room insulation, set temperature, and outdoor weather.
Why is the AC priced at my top tariff slab, not the average rate?
Indian electricity tariffs are telescopic — you pay progressively higher rates as consumption rises. An AC adds to whatever you already use, so its units land on your highest slab, not a blended average. Pricing it any other way would understate the real cost.
Does star rating actually change the running cost?
Yes, directly — star rating maps to an ISEER value, and a higher ISEER means fewer electrical units for the same cooling output. See our 3-star vs 5-star savings guide for the exact annual difference.
Does this include my fixed charge or the rest of my bill?
No — this is the marginal cost the AC itself adds, priced at your top slab. For your full monthly bill including fixed charges, subsidies and duty, use your state’s electricity bill calculator.
How can I reduce my AC running cost?
The biggest levers are: raise the thermostat set point by 1-2°C (each degree saves a meaningful share of compressor runtime), get the unit serviced so the coils and filters aren’t restricting airflow, and if you’re buying new, choose a 5-star inverter model sized correctly for the room — see our tonnage calculator.
What’s the difference between SEER and ISEER?
SEER (Seasonal Energy Efficiency Ratio) is the US efficiency standard, tested against American climate and duty-cycle assumptions. ISEER is BEE’s Indian adaptation, tested against Indian climate zones and usage patterns — so an ISEER rating is the relevant figure for running cost in India, not an imported SEER number.
Why does the same AC cost more to run in one state than another?
Two states can have very different top-slab tariffs, fuel cost adjustments and electricity duty — see the slab comparison above. An identical AC can genuinely cost 30-50% more to run in a high-tariff state than a low-tariff one.
Is a 5-star fixed-speed AC better than a 3-star inverter AC?
Star rating is based on ISEER regardless of compressor technology, so a genuine 5-star rating beats a genuine 3-star rating either way. In practice, though, almost all 5-star models sold today are inverter units — a labelled 3-star inverter AC is uncommon, so this comparison is mostly theoretical.
What is the correct tonnage for my room size?
It depends on room area, sun exposure and floor level — use our AC tonnage calculator for an exact recommendation rather than guessing, since both an undersized and an oversized unit cost more to run than a correctly sized one.
How much does a 1.5 ton AC cost to run per month in 2026?
For a 1.5 ton, 3-star unit at 8 hours/day, expect roughly ₹1,685.19/month in a mid-tariff state like Tamil Nadu — see the slab comparison above for how this shifts across other states, or use the calculator for your exact DISCOM and hours.