>If I said comparing a new car's fuel efficiency to my old one was unfair, because my old one has a lot of problems, you might say that's very fair.
If it's a simple as not driving the old one with punctured tires and replacing those first to get a dramatically different comparison then no i'd say it's unfair.
Replacing a broken thermostat or fixing a rubber seal isn't a huge thing. Why else make the comparison? Who cares about this broken one?
If you're comparing technologies, then you want to eliminate the variable of condition.
If you are comparing the values or efficiency of actual old fridges and new fridges - for example, to decide whether to replace the old ones - then it's false data to assume the old fridges are in the same condition as new ones.
If it's a simple as not driving the old one with punctured tires and replacing those first to get a dramatically different comparison then no i'd say it's unfair.
Replacing a broken thermostat or fixing a rubber seal isn't a huge thing. Why else make the comparison? Who cares about this broken one?