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A Tiny Home That’s Simply Radiant

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radiant Bob "Hot Rod" Rohr
By Bob "Hot Rod" Rohr

I have a hard time sitting still for more than 60 minutes. I’m in my sweet spot when I am building or fixing things, or just generally tinkering.

Certainly, my day job as a trainer for a hydronics and plumbing product manufacturer fulfills my need to be "on the move."

I talk, visit and travel. I enjoy the time I spend in front of a group talking plumbing, solar and hydronics. I jump at any chance to visit jobsites and spend a few hours at a counter day’s event chatting with the guys and gals that "get ’er done." I’m also one of the go-to guys when it comes to updating and expanding our company lab and training facility.

On the road, online or on the phone, hearing stories or jobsite tales and adventurers keeps the momentum going for me.

Another man or woman might enjoy home time with such leisure activities as golfing, touring or sporting events, but for me, my ideal weekend or evening activity includes time in my shop.

Over my lifetime, I have collected quite an array of odds and ends for project building. I’m mostly drawn to metalworkingprojects and hobbies. Copper and steel have been my go-to materials. With just a handful of basic metalworking tools you can cut, bend and assemble a wide range of products. (OK, that handful of tools has grown into a full shop over the years, but still, it’s the creating that I enjoy.)

The raw materials are easy to come by, cheap and often free. I regularly prowl the Habitat for Humanity retail store and a handful of hip salvage businesses.

The creative side of me has had me colouring outside the lines from time to time, taking on things like the odd woodworking project, or even more, so I really shouldn’t be too surprised that a rare moment in front of the television led to one of my more ambitious projects: a Tiny Home on Wheels (THOW).

Join the Movement


The THOW movement is worldwide, and it also includes some truck and bus conversions. If you are interested, search the web for some good ideas on what other folks around the planet are creating to live small, portably and affordably. Regardless of where you live you will find a THOW movement close by. Tinyhousetalk.com is one of my favorite sites for ideas and input.

Getting Inspired


I’m not much of a couch potato. Winter months are about the only time I spend the odd evening in front of a TV screen and it was one of those rare, random channel surfing events that introduced me to the tiny home movement. There are a few tiny home shows on my DVR these days.

Tiny homes are described as being less than 400 square feet in size. This could be a cabin or cottage on a piece of property, but a more recent evolution of the concept is the tiny home on wheels, or THOW for short.

THOWs are along the lines of travel trailers as far as size and portability goes, but they are built more like actual mini homes.

If you have ever spent a winter in an RV you may know how much of a challenge it can be to stay warm and comfortable. (Next time we meet, ask me about a winter in the mid ’80s when I spent the season in a trailer home in the Grand Targhee Ski Area parking lot.)

For weight, space and cost reasons, most RVs and mobile homes have minimal insulation in the floors, ceilings and walls. Keeping them warm and comfortable is an energy expensive proposition. The same applies to the cooling season, as RVs are not very energy efficient vessels.

As I have watched the builds, I rarely see any mention of the plumbing or comfort systems. It’s all about the flash factor, and clever (sometimes wastefully expensive) interior decorating.

So, knowing what I know about RVs and building sciences, I thought I would give it a try. I decided that I’d build a THOW, but with a plumbing and heating spin.

And it didn’t hurt that building the home would also allow me to work on some of the other crafts I enjoy, like woodworking, some finish carpentry and cabinet building, as well as plumbing, hydronics and some metalworking.

Hot Rodding a Tiny Home


Planning out my build, radiant heating was at the top of the list of must-haves. I had plenty of "seeds and stems" around to complete a 160-sq.-ft. floorplan.

I used some leftover radiant panels, installing two loops with two different brands of PEX. Being able to handle the heating load with only 80 square feet of unencumbered floor space was not going to happen, so I added some radiant wall heat as well. The key, I found, with just 160 square feet to work with in the home was to utilize every square inch.

I covered the radiant entry wall in 400-grade polished stainless steel. This allows magnetic hooks and attachments to be used, which means it can be customized to the owner’s needs.

I used slatwall panels in the mechanical room to provide unlimited flexibility for storage configurations. In a small tight space like this, I decided against any fossil-fuel appliances. I chose a small electric boiler to be the heart of the system. The small size and option to mount in almost any position helped minimize the space needed for the mechanicals. I also liked the fit and finish of the jacketing of the unit I used, especially since it is visible in the home.

A small 12-gallon electric tank provides DHW. On my next build, I’m thinking that I would like to try to use a solar thermal system, but that’s a story for down the road.

On the electrical side, a couple 120W solar PV modules and a solar battery provide a bit of 12-VDC solar energy. All windows are operable and I left a space for a small RV-sized ventilation recovery unit. I also left provisions for a small mini-split or window AC, should the owner require cooling.

The entire home is foam-insulated with five inches of insulation in the floor and 3.5 inches in the walls. I could keep it comfortable to work in this past winter with just a 250-watt halogen work lamp, before the heating was completed.

Once I had the wiring completed and the floor covering down, I fired up the radiant floor/walls and remembered what it is that we all love about radiant heat. Ahhh.

Finding a Home


As I started getting calls to purchase the home, I was surprised to find the calls and inquires were mainly retirement age women! I had envisioned this as being a starter home or perhaps appealing to a college student. What can I say? I’m always learning. And I am excited to get started on my next THOW.