When preparing for the future, ours and our children and grandchildren's, one of the things that would be nice to pass on would be sustainable, low maintenance, low cost, multi-generational  housing and shelter. The purpose of a shelter is to keep people dry, warm, and cool and comfortable, and allow them a place to sleep, work, recreate, relax and be safe. This blog article will address the warm and cool aspects. Later ones will address some of the other features. 

When designing and building a house- or even an emergency shelter - there are four things to consider for thermal efficiency and comfort. And the wider your comfort range the better (winter= sweaters and thermals, summer= shorts and t shirts and all seasons = adapting your comfort range to closer to the temperatures outside)

1) Insulation - you hear this one yelled to the heavens and argued about this type or that vs this situation or that. The point is however totally moot if any of the other three considerations are screwed up. Yes insulate, As much as you can afford, but work it in line with the other three considerations. Solid sheets of Styrofoam type material works great for many purposes and are a great use of our Oil Age industry. Solid, well compacted straw-bales (not hay), kept dry and away from cellulose consuming insects (i.e.: termites and wood ants) are also decent and sustainable. Fiberglass is well known, easily obtained, and works well with common popular building techniques- not so well with alternative techniques and can have long term problems if not installed properly (but that can be true of most techniques).

2) Heating/cooling source(s) - you need more than one heat source. Sure a wood stove is nice. But does it fit in your enclosure appropriately? I knew of several homes growing up that had nice big super 'efficient' wood stoves. But when running properly the owners had to open windows because the stove overheated the room it was in.  Human and pet bodies, lighting, cooking, water heating, and solar are all sources of heat. You can also get propane/natural gas, or (ugh) electric heating. If you allow yourself and your home to acclimate appropriately to the environmental temperature (say letting it be cooler inside in the winter, and warmer in the summer) you need less heating and cooling, which means you save energy. Even without insulation. Obviously for long term you want sources that are not grid dependent that can keep you at least somewhat bearably warm/cool. All sources of heat and cooling should be properly sized, bigger is NOT better. Don’t forget to figure out how you are going to get this heat around the home to all the rooms appropriately. If you have the Lucre this last part is what ‘radiant in floor heating’ is for – NOT for the heat source itself, but for getting the heating/cooling around the house to where it is needed.

3) Ventilation and air flow control - If you don't want to breathe your own breath and mold spores you need clean dry airflow through your structure. Ideally the air will be near the temperature you want to keep the structure. Breathing, Cooking, Bathing, Cleaning, etc., all put moisture in the air, if you don't force this moist air out of the home you will get condensation and mold/mildew. So incoming air (conditioned to near the temperature you want it) and outgoing air (taking out the moisture and stink of your living). Fans and the ability to completely close off or open wide up these vents will make for a far more comfortable home. Where I live now has a nice big fan next to the kitchen stove- but it vents straight through the wall and cannot be closed- so when it is negative 40 degrees out the heater pumps heat right out that hole. We covered it ASAP but the jury rigged solution is nowhere near as efficient as a proper closing vent would have been. Earth tubes with solar powered fans may work in some environments if properly designed. Supposedly 100' of PVC pipe buried well below frost line, sloped to daylight for drainage, surrounded by gravel or sand and topped with a bit of insulation can moderate the incoming air to @50 -55 degrees. A solar powered fan to blow air in (that you can turn on and off) and the ability to close either or both ends of the tube makes this well worth looking into. But it won’t work right if you don't control the air infiltration/venting of your home (as much air or more needs to leave through controlled vents as comes in the earth tube, supposedly you can use an outgoing near parallel tube to further moderate the temperatures and control outgoing air. Also note to include removable cleanable screening to all your vents to keep out pests, the last thing you want is a wasp nest in your main vent.

So far Items 1), 2), 3), call for spending some money, labor, and thought on the design. Item 4) however can be the cheapest and most brain dead option.

4) Thermal Mass. Most modern homes completely neglect this cheap option in favor of more expensive industrial options. Earth sheltered homes don't perform well because the earth is a good insulator, Earth isn't a good insulator (even if kept dry, it takes many feet of earth to equal 6 inches of properly installed insulation). BUT the thermal fly wheel effect of a thermal mass such as surrounding earth, (and  minimally because of improved ease in controlling air flow) can be useful. Basements are always at a more stable temperature than the houses sitting on top of them, because the earth absorb and releases the heat slowly over time. The best thermal mass is plain water, (controlled it can be a good thing, uncontrolled flowing past your heated house, it can be very bad) followed by metals (if you are a rich yuppie prepper this means you should make an interior wall of solid gold - lol) Followed by solid masonry and earth. Adobe houses in the SW can be fairly comfortable with their foot thick earth walls because the walls absorb the heat of the day and release it back when the nights get cold. Better still is to insulate the earth or masonry from the harshest exterior temperatures (and flowing water that will carry away the heat) and slowly add a little heat or cooling to the thermal mass over a long time period from the interior of your structure when it is cheapest and easiest to add. Utilizing this flywheel effect and proper ventilation means you have to add far less heating and cooling to the structure during exterior temperature extremes. So your home will eventually remain close to the temperature you set the thermal mass to, for as long as the size of the thermal mass allows. And since the thermal mass can be literally dirt cheap you can use as much of it as you want, the more the better. Imagine every interior wall of your home being foot thick rammed earth - that is a LOT of mass all near a comfortable interior temperature and providing good sound and ballistic protection . If somehow you find that you have too much thermal mass (I can’t imagine how) you just throw some out to make a raised bed for your garden.

The nice thing is all four concepts can be included in new structures, or added to existing ones with a little thought.  Thermal mass is the cheapest concept to implement or retrofit. Build a nice rock or brick wall inside, or indoor planter or hot tub if you want luxury ;-) , or just bags full of compressed subsoil and sand. Plastic and caulking WITH proper controlled vents for air flow costs a little more but done properly has big possible payoffs – be careful when retrofitting, old buildings are used to ‘breathing’ easily, some can have problems if you cut that off.  Insulation with industrial oil age products is one of the best new things ever, get it while you can afford it, and install it with care and it will allow you to minimize your heat sources, and could last generations.

It seems absurd to me how for the past centuries the emphasis has been almost exclusively on improved heat sources, and only for the past few decades has insulation and ventilation control climbed into general awareness. Thermal Mass is still considered an alternative and 'odd' idea, probably because it is so cheap and easy to do that there is really no money incentive for the tax authorities or building companies to embrace it .