Residential Kitchen
In a dwelling unit (residential), GFCI protection is only required for kitchen receptacles that serve the countertop surfaces. There's no requirement to GFCI protect receptacles that serve a refrigerator. Unless the fridge is plugged into a countertop receptacle.
National Electrical Code 2014
Chapter 2 Wiring and Protection
Article 210 Branch Circuits
I. General Provisions
210.8 Ground-Fault Circuit-Interrupter Protection for Personnel. Ground-fault circuit-interrupter protection for personnel shall be provided as required in 210.8(A) through (C). The ground-fault circuit-interrupter shall be installed in a readily accessible location.
(A) Dwelling Units. All 125-volt, single-phase, 15- and
20-ampere receptacles installed in the locations specified in
210.8(A)(1) through (10) shall have ground-fault circuit interrupter protection for personnel.
(6) Kitchens— where the receptacles are installed to serve the countertop surfaces.
Garages, Unfinished Basement, and Other Locations
If the refrigerator is in a garage, boathouse, or unfinished basement. All the receptacles are required to be GFCI protected, so the fridge will have to be plugged into a GFCI protected receptacle.
Why does the fridge trip the GFCI?
Any inductive load when switched off, can produce electromagnetic interference (EMI). This interference can, and often does, trip GFCI devices. Most vapor compression refrigerators have a few inductive loads, any of which could cause the trip.
Is there anything that can be done?
There are devices called snubbers that can be used to reduce, or eliminate the effects of EMI. Installing one between the fridge and the GFCI device, could prevent nuisance trips. The best solution though, is to connect the fridge to a non-GFCI protected circuit.
If that's all it takes, why isn't there already one built in?
While most (all) manufacturers are aware that refrigerators can cause nuisance tripping of GFCI devices, most (none) seem willing to provide a solution. It would be complete speculation for me to try and tell you why they don't care, so of course I'll go through a few possibilities.
- Cost.
Plain and simple, it costs money to implement a solution.
- Warranties and Operating Conditions.
Most refrigerators are designed to operate in a kitchen. Running them in dusty, dirty garages and basements could lead to more warranty covered repairs.
A dehumidifier is about the same as a window AC unit with both parts in the house, for most purposes. They draw just as much power as an A/C unit of similar size (or more if they happen to be old and inefficient.)
Given that the required energy labeling on A/C units tends to promote a degree of of paying attention to that, and it's much less clear on dehumidifiers, I suspect that in many cases the A/C of similar size will actually use less power - and it doesn't make your house hot.
Sure, comparing a room dehumidifier to a whole house A/C, the whole house uses more energy - but it also removes more water from the air, and cools the house. It would only be ANY savings if the whole house was LESS efficient (power in to water out) than the dehumidifier. If you are running the A/C as well, you are also ADDING the heat from the dehumidifier to the A/C load.
In short, run the A/C, don't bother with a dehumidifier unless you have a job that a dehumidifier (alone) is suited for; Which it sounds like you probably don't.
If you want to get "something like that" without the downsides, when your water heater wears out, consider a heat pump water heater - free hot water with a little A/C, or free A/C with your hot water. Still rather expensive, but sometimes with large rebates available too.
Best Answer
I think unplugging the refrigerators will both save electricity and reduce wear on the compressors, although I agree with others that if possible you should measure the usage, in part to decide whether any (possibly small) savings is worth the effort.
Energy Savings
Empty refrigerators are less efficient, since the compressor needs to cycle on and off more frequently due to relatively low thermal mass. If you unplugged the fridge when you weren't using it, I suspect when you plugged it back in it would only take a few hours to cool down. Under normal usage a fridge will have its compressor running about 1/3 of the time, so this will be a meaningful savings. (The fridge uses the vast majority of its electricity running the compressor, so how long it's running for is a good proxy for electricity consumption.)
Wear on Refrigerator
Cycling of the fridge compressor on and off is a primary cause of wear, so unplugging the fridge should be a benefit in that respect. Plus there will be total fewer runtime hours. I don't see how unplugging the fridge for days at a time could possibly damage it. (If you were unplugging it twice a day and forcing it to warm up to room temperature and the cool down, that would be another story.)
Other Considerations