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Every once in a while, I have the opportunity to work on a unique project involving the STEP Warmfloor electric underfloor heating product. We’re in the process of completing one of those projects right now.

The home involved in this project was designed by an internationally-renowned architectural firm in Minneapolis, which is known for advancements in green home solutions and for giving every home a one-of-a-kind look. In addition to wanting a unique design for their home, the homeowners also wanted it to be comfortable and planned on installing some form of radiant floor heating – this is where we stepped in.

In September of 2011, I met with the project’s general contractor, his electrical sub-contractor and the homeowners. The electrical contractor had worked with STEP Warmfloor before and thought it would be a perfect fit for this home.

Comfort and energy efficiency were important criteria for this home. These are just a couple benefits of STEP Warmfloor. Others include:

  • Low voltage – 24 volt AC or DC
  • Self-regulates for energy efficiency
  • Primary heating capabilities
  • Renewable energy compatibility – can be powered by solar or wind
  • Maintenance free
  • Reliable and safe

In addition to comfort, the homeowners also wanted to incorporate green home solutions and decided to use solar energy panels to offset the home’s energy use throughout the year. This type of configuration is a perfect match for the STEP Warmfloor heating system, as it can be powered directly from a solar powered 24 volt DC power source, or it can work from the grid connected AC power. designed the primary heating system by calculating the heatloss of the home. The homeowners also wanted air conditioning, so they decided on a forced air delivery system to condition the living space for the summer.

Let’s fast forward to November 2011 when work began on the home. The day I arrived to look over the STEP Warmfloor installation was probably one of the coldest days of the year. I must admit that I felt sorry for the electrical contractors who were making the wiring connections on the heating elements. The temperature was about 8° F and it felt even colder, thanks to a frigid north wind that was blowing close to 25 mph.

For this particular application, we decided to install the STEP Warmfloor heating element below the concrete slab. As you can see from the photo above, the building foundation is on grade. The design of this total space heating system is very similar to that of a hydronic or water based tubing radiant floor heating system. A 2” polystyrene insulation panels (4’ x 8’) were laid on the ground. The same types of insulated panels were installed vertically along the perimeter of the foundation. This will reduce downward and outward thermal heat loss. The insulation is a critical step to ensure overall system efficiencies and comfort.

The STEP Warmfloor heating element was easily rolled out onto the polystyrene and secured with cap nails. The cap nails were basically pushed between the open slots of the STEP Warmfloor heating element and into the polystyrene. Their purpose was to prevent the heating element from moving when concrete was poured.

The heating elements were connected to a number of low voltage transformers located in a separate room. The main room of the home is all controlled with one easy to use thermostat, much like any other central heating system. Additionally, the electricians wired the STEP Warmfloor system to a separate metering system. This optional metering system will help measure the power draw of the heating system from the other electrical loads in the home. Once the home goes through a heating season, will be able to determine the measured (metered) energy use of the heating system in comparison to the calculated heat loss. This will provide valuable energy efficiency data to show architects, builders and electricians. Not taking into account the solar panel system and other green home solutions in this home, our calculations show that it will be less expensive to operate than a natural gas hydronic system. I can’t wait to tell you the results!

In a couple of months, the home will be staged for the Homes by Architects tour. is one of the sponsors for the home and will meet with future homeowners, architects and designers during the tour to show them how to use STEP Warmfloor’s technology in future home designs. Stay tuned for a follow up blog as the project continues. The Homes by Architects tour is taking place on September 22-23, 2012 throughout the Minneapolis/St. Paul metropolitan area.