If there’s one thing we can count on in any disaster, it’s the loss of electrical power. Our aging electrical grid is highly susceptible to damage, causing disruption of electrical power anytime there’s a major storm, let alone some sort of major disaster. But in today’s society, we are highly dependent on that electrical grid for a number of things, one of which is keeping our home’s warm.

On top of the risks caused by natural disasters, our electrical grid is recognized as a prime target for terrorism, cyber-warfare and even direct warfare through the use of an EMP. Any terrorist organization could take out electrical power locally, and with a concerted effort could take it out across the nation.

Most homes today are built with forced air heating and cooling systems. Those that aren’t might have some sort of hot water heating system. In either case, the system doesn’t work without electrical power. For that matter, many homes’ systems won’t work without a constant source of natural gas, either. But natural gas is much less likely to be shut off than electrical power is.

Either way, we could find ourselves in the middle of a winter snowstorm, without the means of keeping our homes warm. That’s not just an inconvenience, it is a very real danger to our families. Without heat in our homes, we are at risk of hypothermia, one of the biggest killers in nature.

Maintaining our body temperature is the single most important part of survival. According to the rule of threes, without adequate heat to maintain our body temperature, we can die in 30 minutes. In some extreme cases, such as getting wet in the cold, that 30 minutes can be cut considerably. Early stages of hypothermia can set in within minutes in such a case, preventing us from having the mental capacity to protect ourselves and prevent the hypothermia from becoming more severe.

The best solution for hypothermia is to deal with it on a preventative basis. In other words, to make sure that we are able to keep ourselves warm, even in a crisis situation where we have no electrical power. This must be part of our survival plan, both for sheltering in place and for bugging out.

I need to add here that hypothermia isn’t just a wintertime problem, although I’m writing about it as if it was. Every summer, people die of hypothermia in the Colorado Rockies. Typically, they fall in the water shortly before sunset, and can’t get back to their vehicle before the temperature drops. While it’s not going to drop below freezing in the summertime, it can drop enough that they end up losing too much body heat and hypothermia sets in.

Once hypothermia sets in, mental capacity starts diminishing. In first stage hypothermia, with a drop in body temperature of only two degrees, a person can walk right by their car, without even recognizing that it is a source of warmth. By the time a person reaches second stage hypothermia, which is only a drop of four degrees in the core body temperature, one reaches a point where they are incapable of thinking of protecting themselves. Without outside intervention, they will die.

So, we must make the ability to protect our body’s heat an integral part of any survival plans. That means having the means to produce heat, as well as the means to protect the heat that our bodies have.

The Three Elements of Keeping Warm

There are three basic parts of keeping warm. While we can actually manage to survive with any one of those elements absent from the equation, we can’t survive for long if all three of them are removed. We need at least one, and preferably two of them in place, in order to survive.

Our bodies produce heat all the time. The chemical reactions that are part of our bodies metabolism all generate heat. As long as there is nothing wrong with our health and nothing that is stealing that heat from our bodies, we will maintain a core temperature of 98.6°F (37°C). But, there are many things that can work against us, stealing our bodies heat.

Basically, nature has three main weapons it uses to steal our bodies heat. Those are:

  • Ambient Air Temperature - Any time that this is less than 98.6°F, we are radiating heat into the air around us. The colder the temperature is, the more heat we radiate into the air.
  • Wind - Wind moving past our bodies removes heat from our bodies faster than still air does. This is because the bubble or warmed air that we form around us by radiating heat into the air is removed, and replaced by cold air. In addition, the air moving across our bodies uses our skin as a heat exchanger, taking heat directly from our bodies.
  • Rain and Water – Water is the most dangerous thing that nature can throw at us, having the ability to draw a lot of heat out of our bodies. This is partially due to the temperature of the water itself and partially due to the thermal conductivity of the water, which is much higher than air. So, even if water and air are at the same temperature, water will draw heat out of our bodies faster.

The worst combination that nature can throw at us is a combination of wind and rain. With that, the effect of the water is increased, as the wind will cause the water to evaporate quicker. At the same time, it is constantly providing a fresh supply of cold water to be in contact with our skin.

The three elements of keeping warm all work to counter those things that work against us. How they do this is different for each of the elements.


Shelter helps us in that it prevents nature from stealing our body heat. It is a barrier between us and the things that nature can deploy against us. Rain can’t fall on our heads and the wind can’t blow against our bodies. Shelter alone can make a huge difference, simply by being a barrier between us and nature.

Shelter that is combined with insulation works even better, because the insulation will help keep the heat inside the shelter from escaping. While any barrier has some insulation value, we must take into account that ambient air temperature, wind and rain cause the shelter to lose heat, just like they cause our bodies to lose heat. Insulation slows this process.


When we talk about insulation, we’re really talking about two different categories of insulation. I’ve already mentioned the first, that is insulation for the shelter we occupy. That helps keep heat inside the shelter, separating it by a multitude of layers from the external ambient air temperature.

The second category of insulation is the clothing that we wear. Yes, clothing has an actual purpose, besides making us look better and allowing women to practice their favorite sport… shopping. That purpose is to help us stay warm. It also protects our skin from the sun, preventing that sort of damage from nature as well.

Insulation works by creating a massive number of layers of air pockets. What this does for us is allow a huge number of temperature steps between the inside air temperature and the outside air temperature. If you were to map out the temperature between the most interior layer of air and the most exterior, you’d find that they gradually moved from warm to cold, with the inner layers being warmer and the outer layers being colder.

External Heat

When we talk about external heat, we’re not talking about outdoors, but rather any heat source that is outside of our bodies. The warmer the ambient temperature is, the less heat our bodies have to produce. That saves the energy in our bodies for other tasks, such as moving muscles.

The most common source of external heat is fire of some sort, although that is not the only source of heat we have available to us. Solar heating is quite effective, although it requires special planning and construction. Nevertheless, it has one huge advantage over any other source of heat… you don’t have to worry about running out of fuel. The sun’s fuel will far outlast any of our lifetimes.

The furnace in your home is producing external heat. But as I said in the introduction to this article, you can’t depend on it in the midst of a crisis. You’ve got to have some alternate source of external heat to use, which will operate without any electricity.

Ensuring Your Shelter Will Protect You

While most people think about heat sources first, I’d like to start out talking about your home. It really doesn’t make much sense to talk about generating heat, if you can’t make sure that the heat that you generate stays inside your home. A properly built home will be mostly airtight and well insulated, to help ensure that the heat stays inside.

Unfortunately, not all homes are well built. In fact, if you don’t have a custom-built home, I’d have to say that chances are that your home isn’t as well built as you think it is. Few contractors pay as much attention to detail as they should, rather looking for ways to cut costs and get the job done quickly.

Many public utility companies, some government agencies and even some non-profit organizations offer home energy audits. In these, experts comb your home, looking for places where energy is being wasted. One major part of that examination is to look for places where heat is being lost, usually due to poor construction.

Of course, you can do this yourself as well. If you do, be sure to check:

  • Air leaks at windows and doors – Check for air drafts. It’s helpful to do this when it’s windy, as they will be much more obvious then. Add weatherstripping, door sweeps and new seals as necessary.
  • Air drafts in the basement – Many basements have air leaks where the wood framing meets the cement foundation. These are easily sealed with expanding foam insulation.
  • The thickness of the insulation in your attic – Insulation packs down over time, making your attic insulation thinner and therefore less effective. You may need to add more, especially if your home is over 25 years old.
  • Insulation in the walls – This is hard to check, as it requires putting holes in the walls. But if the insulation in your attic has packed down, then it probably has in your walls as well. You may need to add blown-in insulation to fill the walls again.
  • The windows themselves – Windows are the worst insulated part of any home, Even double-pane windows only have a R-value of 2.0. While more exotic window types have higher R-values. Few people have them due to their high cost.

As part of your survival planning, you should have a means of increasing the R-value of your windows. One way is to cover them with blankets, or quilted curtains. Another is to cut sheets of Styrofoam insulation and put them over your window openings. While not a perfect answer, as it cuts down the available light, it will help keep you warmer.

Let’s Talk Heat Sources

Most preppers think of wood first, when they think of heating. That probably has something to do with wood historically being the most common source of heat. It has a large number of advantages, such as being renewable and being something that anyone can harvest themselves. In a TEOTWAWKI situation, it may be one of the few heat sources available to us.

I don't want to spend a lot of time talking about wood heating here, because I've talked about it elsewhere. But I do want to mention this. In our theoretical TEOTWAWKI situation, we won't be the only ones trying to harvest wood for cooking and heating our homes. All of our neighbors will be doing the same thing, even those who are not prepared.

For that reason, we shouldn't depend on wood only. We should have at least one other heat source, if not more. Ideally, we should have a heat source which doesn't require us seeking and collecting fuel, although there aren't too many which qualify for that.

One such method is geothermal heat. But geothermal is extremely expensive, not something you can do yourself. Nor can it be done everywhere. In many parts of the country, the geothermal layer is deep enough that it isn't financially practical to try and reach it. That's part of the reason why each system has to be individually engineered to match the geothermal situation where it is being installed.

Passive Solar Heat

The other renewable heat source is solar. While true solar homes have to be designed specially to take advantage of the energy that the sun provide, it is possible to retrofit many homes to have at least some solar heat.

Adding a sun room to a home is a great way of adding some passive solar heating capacity. But even if you can't do that, you could increase your passive solar heating capacity by adding additional windows on the south-facing side of your home. With ample window surface, all you need is something dark colored for that sunlight to hit, and you're creating heat.

In a typical passive solar home, the floors are dark and attached to a thick foundation of cement or stone. This thick mass acts as storage for the heat absorbed from the sun. But if your home is well insulated, storing that heat might not be necessary. Simply allowing it to radiate into the room can warm your home enough, that it will stay comfortable until the next day.

Simpler Passive Solar Heat

Even if you can't build a sun room or add additional windows to your home, you can still take advantage of passive solar heating. Whatever south-facing windows you have can be used as solar collectors, bringing sunlight into your home to be converted to heat.

One of the ways that people do this is by making tubes out of empty soda cans; cutting the bottoms and tops out of them and gluing or taping them together. Painted black, an array of these filling the window will absorb a lot of sunlight and convert it to heat.

The same thing can be done with aluminum flashing and plywood; coating one side of the plywood with the flashing and painting it black. The plywood and aluminum composite needs to be cut so that it's a little shorter than the height of the window opening and a little wider than that. It is then mounted to the wall, covering the window opening, but leaving a gap at the top and bottom. These sorts of devices work by convection, so the air will move through the heater by itself, being warmed as it rises.

Active Solar Heat

Active solar heat is considerably more complicated to build and install, than passive solar heating is. But it is still something that you should consider, especially if it is difficult to install passive solar on your home. These systems are called "active" because they require a pump to make them work.

I've seen a number of homemade solar hot water heaters and they are all essentially the same. There's a glass-fronted box, that's painted black inside, something like a shadowbox. Copper tubing is run through the inside of this shadowbox, for the water to run through. Water is circulated by a pump, with teh warmed water being pumped to a tank for storage.

With a slight modification, this type of system can become an active solar heating system. All you need is some sort of radiator inside the home, where the heat trapped in the water can radiate into your home. You will need some electricity for this system, but a small circulating pump won't need anywhere near as much electricity as your furnace uses.

Ideas From Our Ancestors for Keeping Warm

The need to keep warm in wintertime isn't something new; our ancestors have had to deal with this problem throughout history. While most of them used wood for heat; they did whatever they could to get the most out of the heat that they were producing. We could use to learn from their example.

I’m not talking about our grandparents here, or even our great-grandparents. I’m talking about people who lived in the time of the horse and buggy, the early days of our country and throughout the westward expansion. Those people were rather inventive in staying warm, even without our central heating.

Only Heat Part of the Home and Use That Part

Central heating is an old invention; but the use of central heating throughout a house wasn't common until modern times. Korea has had a central heating system, which had clay heat ducts built into the floor for centuries. But few other places in the word used such a system, as they were too inefficient.

What our ancestors did instead, was to heat just the living spaces in their homes and not the bedrooms. Their homes were often built with those living spaces open to each other, so that they could be heated by a common fire. A modification on that would be to use the fireplace as a means of separating two living spaces, such as the dining room and the living room.

While this meant that the bedrooms were cold, little time was spent in those bedrooms, other than to sleep. A fire in the living room and another in the kitchen stove was enough to keep everyone warm through the day, as they did their various activities.

Dressing Warmly, Even at Home

We are accustomed to dressing in lightweight clothing and then putting on a coat when we go outdoors. But not everyone in the world does things that way. I've spent a fair amount of time in Mexico, and their homes are unheated. When it gets cold, they simply bundle up, wearing coats, hats and even gloves indoors.

The best way to use clothing is to dress in layers. That way, you can take off or add layers as needed to match the changes in temperature. Typically, the coldest time of day is early in the morning, when people are leaving for work. So, if you use enough layers in the morning to keep you warm, you should have enough for the whole day. Then, as it warms up, you can take layers off, keeping you from overheating and sweating.

Lots of Blankets

Keeping warm at night was even easier for our ancestors, than keeping warm during the day. They'd pile their beds high with blankets to hold in their body heat. Since their bedrooms weren't really heated, they had to count on their body heat to keep them arm at night. Those blankets helped.

But there was something else they did, which was even more useful; they shared body heat. King-sized beds didn't exist back then, so couples slept close together, where they could share their body heat. Children often shared beds as well, rather than each having their own. That allowed them to share body heat as well, helping to keep each other warm.

Use a Bedwarmer

When you get in bed after a long day, the sheets are typically rather cool. But that wasn't so for our ancestors. They used a bedwarmer  before getting in bed, making sure it would be comfortable.

Contrary to popular belief, bedwarmers weren't filled with coals from the fire. If they were, they'd make the bed dirty with charcoal dust. Rather, they would heat rocks in the coals and put those rocks in the bedwarmer. Although the rocks were heavier than the charcoal would be they didn't make the bed dirty.

Carry Heat With You

When our ancestors had to leave home, they didn’t do so in a heated car. Nor was the place where they were going likely to be heated. Only wealthier churches were heated and not all stores were. So, if people wanted to keep warm, they had to dress warmly. It also helped to carry along a little heat with them.

No, I’m not talking about carrying a gun. I’m talking about carrying a hot stone with them. Typically, this was soapstone; but really any rock would do. They’d put it in the coals of the fire to heat up, then when it was time to go, they’d take the rock along with them. Some sort of carrier was used, usually made out of canvas or some other heavy cloth.

The stone could be placed on the floor of their carriage or wagon, by their feet. Then a blanket was spread over their laps, helping to hold the heat from their stone in. While that didn’t keep the whole body warm, it did help to keep the feet and legs warm.

Many of the old churches had family pew boxes, especially in the northeast. Individual pews were surrounded by a low wood wall, usually made of finely carved wood. This wasn’t for exclusivity or décor, it served the same purpose of helping keep families warm during church. They would carry their soapstone into the church and put it under their family pew (yes, many families “owned” pews) and spread the same blanket they had used in the carriage over their legs.

While carrying around a ten pound rock with you isn’t the easiest way to have heat, it’s better than nothing. Not only that, but it’s a fairly easy way to carry some heat around with you. The rock released the heat slowly, so it lasted quite a while. There are lots of other ways that the same idea could be used, such as heating a workshop, office, bathroom or bedroom.

Dave Steen

About The Author: Dave is a 58 year old survivalist; father of three; with over 40 years of survival experience. He started young, learning survival the hard way, in the school of hard knocks. Now, after years of study, he's gray-haired and slightly overweight. That hasn't dimmed his interest in survival though. If anything, Dave has a greater commitment to survival than ever, so that he can protect his family. Click Here To Read More About Dave

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