That probably very much depends how often you open it. If you open the vertical fridge often then the difference might be larger. Vertical fridges in supermarkets are a crime IMHO.
Supermarket fridges benefit from having the compressors outside which can help tremendously depending on the climate.
A modern house conditions the air inside to a certain temperature (often heating it up) and then has a box inside that is conditioning the air (often cooling it back down to outside temperature).
It likely doesn't. We have a relatively small (European-sized) fridge that, according to EU energy label, should consume 183kWh a year or 0.5kWh a day. I was surprised when the real consumption I measured during normal use, set at 2.5°C, was almost twice that. Even never-opened measurement over a weekend showed slightly more, trough within measurement error.
2.5°C seems very cold for a fridge and is likely well below the standard that the EU energy label uses (for reference, FDA recommends 4°C). How warm do you keep the kitchen that it sits in?
