Removed lots of fluff with the vacuum cleaner. It was on the grille and behind it on the coils. After this, the freezer again reached its normal -18°C.

Many websites and pamphlets state that, for energy efficiency purposes, you should clean your refrigerator coils. In most cases this is not a good idea. If the coils are near the floor, they may become plugged, and if they are plugged, it is likely to be beneficial to carefully clean them. Care must be taken to avoid damage to the coils.

One peer reviewed journal article on the subject states that there are no measurable savings from cleaning coils.[1] An article from Lawrence Berkeley National Laboratory calls attention to three drawbacks to this myth[2]:

1. After cleaning, residents won't see any changes in their monthly bill, leading to apathy.
2. The residents may be unable to clean the coils.
3. Every recommendation made to the consumer is an additional thing they have to do.

Other energy sites, home energy consultants, and inspectors concur that there is little to no benefit from cleaning coils, and some state that there may be additional dangers such as breaking the refrigerator,[3] with one stating "This is a classic example of a widely held belief based on assumptions rather than measurements."[4]

On the other hand, the Home Energy report [5] states,

'Even if maintenance did not improve the aggregate energy consumption of the group, it was expected to improve the efficiency of some refrigerators--those most in need of maintenance. We checked to see if the units with plugged condensers saved energy as a result of maintenance. In five cases, the condensers were plugged. Of these five units, two had marked decreases in energy use after maintenance, and the other three units showed no such decrease. All units with plugged condensers had the coils mounted on the bottom.

In other words, some designs of refrigerators benefit from coil cleaning and some do not.

## References

1. A. Meier, A. Megowan, B. Litt and B. Pon, The New York refrigerator monitoring project, Final Rep. No. LBL-33708, Lawrence Berkeley Laboratory, Ontario, Canada (January, 1993)
• Abstract: A report to improve understanding of energy performance in old and new refrigerators in New York State was cosponsored by the Empire State Electric Energy Research Corporation, New York State Energy Research and Development Authority, Electric Power Research Institute, and the US Department of Energy (DOE). Laboratory test procedures from the DOE and the Japanese Institute of Standards were conducted on 24 new refrigerators of various types to determine relationships between the measured energy consumptions and the manufacturers labelled energy use. These new refrigerators were then placed in homes in the Rochester, New York area and monitored over eighteen months. Older refrigerators already in home use were also studied to determine energy savings resulting from conventional maintenance measures and from replacement with die new units. The manufacturers labels accurately predicted the refrigerators` test energy consumptions, but the labeled values overpredicted their energy use measured in the field by 13 percent. Replacement of old refrigerators with new ones saved 60 percent of annual energy use, with utility peak power savings of 190 W and 150 W per replaced unit in summer and winter respectively. For the group as a whole there were no measurable savings from maintenance. [bold added by editor]
2. Hawkeye Home Inspections & Environmental Testing (Certified Master Inspector)
3. City of Columbia (informed by Sciencebeat)
4. Home Energy Magazine Online January/February 1993