I've seen some claims on social media that Earthships don't work in northern climates. Our Earthship has been providing for us for well over a decade, located north of 54.5 degrees latitude (1 1/2 hours north of Edmonton). With that much experience with these structures, allow me to share our observations so that people looking at building Earthships can do so based on actual observations rather than conjecture.
Our climate is extreme. Over the past five years we experience several seasons where we had snow on the ground for six months. Our winters will drop to -40C/-40F or colder. This past winter we had six weeks straight of -30C/-22F to -38C/-36.4F. Summers are short and hot, with top temperatures reaching over 30C/86F but averaging in the low to mid 20C/68F. Where we built, we experience 88 frost free days or less, depending on the season.
Our climate here is shifting and it is common to have frost in June and August which makes growing crops challenging. Building structures that perform well in this environment without external support is equally challenging.
To manage expectations: If people are expecting earth rammed buildings to maintain 21C/70F all year around, then go live in a traditional build home. Alternative housing is not about maintaining room temperature all year long, but rather allowing the building to breath and adapt to the environment it is built in without being attached to the grid. This is about living within the ebbs and flows of that environment.
We started our project in 2007, building the first of two earthships on this land. In 2008 we started the second home, which is the one we are living in now. At the end of the season we were unable to complete the building before winter set in. We had the tire wall done, the south wall framed and the roof was up. We put up a sheet of 6mil plastic on the outside and inside of the wall plus we had plastic up for the ceiling. No glass or insulation was installed. A traditional build home would have froze within days and reached bone chilling temperatures reaching -40C/-40F.
The coldest temperature I recorded in our earthship that first winter was -4C/25F. On sunny days, the sun that could get through two layers of cloudy 6mil poly still managed to heat the building to +10C/50F, despite -40C/-40F temperatures outside. Please remember that these temperatures were achieved with no glass or insulation of any kind. The thermal mass was doing all the work to regulate the temperature of the living space inside.
In 2009 we put insulation into the attic, installed the windows and got the building into a position that we could live in it. It takes about two years to 'charge' the thermal mass, which required burning wood to help with the charging process. Thermal mass stores heat like a battery stores electricity. When we build thermal mass buildings, we need to pump heat into the thermal mass until it finds equilibrium. Heat travels slowly through thermal mass, which is part of why they work so well. The ambient temperature of the thermal mass within our earthship now sits around 17C/63F through the winter and 19C/66F during the summer.
Ambient temperature of the air within the earthship is dependent upon the temperature of the thermal mass and the outdoor temperatures. During the winter, we only burn wood during the day and we only do that to increase the air temperature to 21C/70F. At night we let the fire burn out and the temperature within the earthship will drop to about 15C/59F. We let the heat stored within the thermal mass do its job and it does it brilliantly! In fact, it works so well that our cisterns are buried at the east end of the building and the corners are exposed to these extreme temperatures. While we get ice inside, we have always been able to draw water from the bottom of the tanks. We have never had our water pipes or pumps freeze.
On some crystal clear winter days when the temperatures are below -40C/-40F, we will find the solar gain into the earthship to be so intense that our internal temperatures have climbed to +27C/81F with no wood heat. We open the windows and doors when most think we are crazy.
Technically, if all hell broke loose in the world and we could not to burn wood at all, our earthship would not freeze and it would keep us alive all winter long. There is no other building technology that can make such a claim. Every other building, whether it be traditional stick built, straw bale or even hempcrete buildings would all freeze without other heat sources. Some in a few days, others would take a few weeks, but they would all freeze putting the occupants in danger and risking their lives.
During the summer, the temperatures within the earthship will rise to about 24C/75F, but will drop back down to 19C/66F during the night. We never suffer during the summer heat wave where traditional homes struggle to cool off and they need air conditioners to cope. Earthships and other thermal mass buildings draw in that heat and automatically cool the air within the living space. During the summer, we always sleep with blankets while our neighbours are awake, nude on top of their sheets with fans and windows wide open.
These numbers that I just shared reflects an earthship that is not even complete. The design for northern climates calls for an atrium, which provides a buffer between the earthship and the extreme temperatures outside. We anticipate that when the atrium is complete, the differentials between the highs and lows within the earthship will shrink considerably and further reduce our desire to burn wood during the winter time to make things more comfortable.
Our Atrium, partially complete
We do this without electricity, natural gas, heating oil or other grid provided services.
While the goal and expectation of grid homes is to maintain 21C/70F constantly all year long, don't expect off grid homes to perform the same way. If you do, then you will be disappointed. These buildings are meant to ebb and flow with the changing seasons. Modern society is so disconnected from the flow of seasons that people have no idea how to reconnect. Earthship temperatures fluctuate with the seasons. The temperature of the thermal mass changes between 2-4C from summer to winter while we experience interior temperatures shift 10C while outside the swing is an astonishing 80C/139F.
That is what thermal mass buildings are designed to do. They are meant to significantly reduce the swings in temperature within the living space, not keep it at a constant 21C/70F. If we decided to not burn wood within our earthship the interior swing would be about 20C. If we completed the earthship and decided not to burn wood, we anticipate the swing to be as low as 10C from summer to winter. In my opinion, that proves these buildings do indeed work!
For us living off grid, these temperature fluctuations are more than enough to consider the earthship the most valuable tool we have. It not only allows us to maintain a healthy living environment, but it also provides water, food, power and waste management on top of all the other features. The biggest bonus is that during an emergency, especially during the winter, we would survive and be able to keep all our food stuffs from spoiling in the process.
I challenge anybody to try and come up with an alternative building structure that can do all this, in extreme northern climates without the need for external grid connected services. To claim that these buildings fail due to the extreme cold ambient temperatures of the earth in these environments, is blatantly false.
I know of other thermal mass buildings made of cement blocks rather than tires, and those buildings perform spectacularly as well. Don't let people who have never lived in these buildings suggest that they don't work.