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My electricity bill rose 30% this summer – could it be the dirty unit?

Editorial guide · Updated 18 September 2026

In short Short answer: realistically, dirt explains part of it, not all – a clogged filter alone costs 5–15% of the unit's consumption, and a dirty outdoor coil adds a few percent through higher condensing pressure; the rest is probably the heat (more running hours) and energy prices. But at 5 years without cleaning, a recoverable 10–20% on an 18,000 BTU unit running daily is not small – the clean pays for itself in two or three months.

This page explains a situation in an editorial format. It is not an open discussion board or a verified customer review. Contact us on WhatsApp about your own appliance.

Situation discussed

Bragadiru, house, one large unit in the living room (18,000 BTU Gree, 5 years old), used daily. The July bill was about 30% higher than last July, same habits (I check the meter). It has never been cleaned. Realistically, how much of the rise can be from dirt?

Editorial explanation · Revizie AC

What is really happening

The two places where energy is lost are the coils: an evaporator coated in biofilm and dust transfers less heat and passes less air (studies show 5–7% airflow lost and higher fan power as it clogs), and a dirty condenser raises the pressure the compressor works against – the biggest consumer in the unit. The DOE recommends exactly the annual check of both coils as an efficiency measure. What cleaning cannot do: make up for a summer with 10 extra heatwave days.

Explanatory diagramEstimated energy: power × time
Estimated energy: power × time
  1. Average electrical input, in kW.
  2. Operating time, in hours.
  3. Estimated energy, in kWh; actual use varies.

BTU describes thermal capacity, not electrical consumption directly.

What the studies say

What we do on site

  1. We measure the grille temperature split beforehand as a reference.
  2. The 18,000 BTU indoor unit: sealed double cover (longer, for the big casing), alkaline detergent, adjustable pressure wash of evaporator, roller, pan and hose; sanitising; filters.
  3. The condenser in the yard washed in place, with detergent and low pressure, from inside out.
  4. We measure the split again and show you the number.
  5. For 18,000 BTU, price by quote – we give it by phone once you describe the unit and access.

What you can do yourself

  • Read the meter for a week before and a week after cleaning, at similar outdoor temperatures – the only honest test.
  • Filters every two weeks; set 25–26 °C; doors closed while it runs.

What NOT to do

  • Do not expect '−30%' from cleaning; whoever promises that is selling.
  • Do not accept 'refrigerant top-up for consumption' – unrelated.

Prevention

Large unit used daily: annual clean before the season and filters every two weeks – the cheapest energy saving in the house.

When to call us

0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; Bragadiru is in our area.

Coil fins full of dust and fluff, before cleaning
Coil fins full of dust and fluff, before cleaning
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The information on this page is educational and based on cited sources; it does not replace medical advice. We do not do repairs, installation or refrigerant circuit work.