I was pretty impressed by something my brother did last fall, and it was a light bulb moment for me. He was checking out some rural land that he intends to buy and decided to live in the falling-down house on that land for several weeks but the utilities were turned off. He has done so much camping that living off the grid for several weeks was no problem. When he was indoors he spent most of his time in one room and used a small propane powered heater for heat, for light he used his battery-powered light from a tool set that he already owned, and the radio from that tool set also had a micro USB port he could use to charge his cell phone and his iPad, as well as play the radio. He also had a small battery bank that he used for some charging. He had a propane powered cook stove to cook his food, he hauled in jugs of water, and used a lot of non-perishable food except for some things in a super-efficient cooler that only needed fresh ice every couple of days. He was able to go to a neighbors house twice a week to recharge the batteries he needed for the light and radio/charger. He was able to drive to a convenience Mart some miles away to get fresh ice and food. I think the propane tank he used lasted for quite a few days, and he was using the sort of small propane tank that’s easily available and often used for BBQ grills. He was comfortable and well fed as he checked out that property, and I think that’s a pretty good example of how you, too, can be comfortable in a grid-down or utilities-off situation. This presumes that you can get someplace to charge your batteries, so doesn’t apply to all situations, but I thought it was a good concept.
This applies more to a temporary grid-down situation than to having your utilities shut off, but you really can be off-grid in a basic way and still be comfortable. You would want to either have a smaller room (maybe 10′ x 10′) where you could close all your doors or be able to put plastic up in any doorways that didn’t have a door in them, in order to be heating a smaller space, which requires a lot less energy/fuel (in other words, less propane). If you are without grid power in a standard american house and the temperatures outside are near or below zero you may have to winterize the rest of your house – drain the water lines, put anti-freeze in your toilet tank and bowl, drain the water line going to your refrigerator. That would be more necessary in an extended power outage – if the temperatures in the house get to below freezing any sitting water is likely to expand and break things. If you had hot water heat, you’d need to drain that system too.
If you’re living just-off-grid (you don’t have utilities but places accessible to you still have utilities) your best bet for showers is to go elsewhere – a gym membership is often quite inexpensive, and would include all the hot water showers you would like. Laundry can be done elsewhere.
If you’re trying to live off-grid in the summer heat a fan is your best bet since air conditioning takes so much power.
If you were going to be just-off-grid for an extended time, I would highly recommend either buying or building a solar oven. There are lots of examples of solar ovens that you can build yourself on youtube.com – though if you can buy one you’ll probably really appreciate the power and convenience of a professionally made oven.
And yes, there’s always the waste disposal issue – as in, human waste. If this is a very short term situation, a trash bag in a trash can can be utilized. For longer term comfort, a 5 gallon bucket, a toilet seat and sawdust are probably your best bet. People do compost human waste, but you need to learn how to do it properly or you will have a stinky health hazard to deal with. There’s lots of info on this around the web.