The short answer is yes and here's one way to do it.

Trombe Walls
Trombe walls are great. They’re silent and maintenance free.  Once installed they use no energy besides the sun that heats them and they can give heat for a lifetime. What that means is they're free to run. So why don’t we all have Trombe walls in our house?  

How it works
Trombe walls utilise the heaviness of mass to store heat.   This mass referred to as “thermal mass” is coloured black on the surface where the sun hits it.  The black absorbs the sun’s energy into the wall.  A layer of glass keeps the Trombe wall’s heat from escaping outside and can work to create a warm air current. 

a tiny Trombe Wall
Limited space and keeping the weight down were big factors when adding things to this Tiny House.

So, how do you make a wall heavy enough to act as thermal mass, but not add too much weight for travel?

Water! More specifically, custom built water-tank walls.
Easy to fill when parked and easy to empty when it’s time to travel.  

Below is a slideshow showing the Trombe walls in the Solar Tiny House.  I didn't show the top hatch in this drawing.

Why insulate
Fully insulating these trombe wall/water tanks, retains the heat until you’re ready to use it.  When ready for some warmth, just open the insulated hatch on the top and voila!  The warm surface radiates heat into the room!

Super charging the Trombe Wall
We could stop there, but let’s take it a step further.

Less waste
The thing about having off-grid solar power is that on a sunny day your batteries can get fully charged before the sun goes down.  Sometimes even before noon!  So, where does the excess power go?  Many times it's just wasted. 

Load diverters
That's where load diverters come in. Once the batteries are topped up the load diverter redirects the excess power from charging the battery to another function. Like 12v heating elements in the Trombe wall.  This would boost the temperature of our thermal mass, making the trombe wall an even better heater.

Your opinion
What do you think of Trombe walls?  What would happen if everyone who's located in a cold climate added Trombe walls to their house?

Tell us your thoughts in the comments below.

I came across this competition for designing Tiny Houses.  How fun! 

I knew that entering the Tiny off-grid house competition would be a great way to get some of the interesting ideas I've been contemplating, out into the world. Except for one catch. There was only two weeks to get my submission in! 

While it's true I work best under pressure, I was heading overseas in a few days. This was going to be a challenge for sure.

This earthship inspired design can grow food year round. 
Folding out the greenhouse effectively doubles the covered living area, which is a big deal in a small space.

I've incorporated a number of hidden features which make it super energy efficient. 

Simplesolarhomesteading.com is holding the first ever tiny off-grid house design competition. Submission entries closed on June 30th and judging will be announced  July 31st. 

Check out everyone's designs and leave lot's of feedback to help LaMar judge the contest!

The Tiny Off-Grid House -  Design Contest 2014