The post last week was Part 1 on this topic, and it included an overview of how the system was installed.  In this week’s post, we’ll get into a little more detail of how it worked and the overall cost of the system.

If you remember from Part 1, the PEX tubing was buried in the concrete in a series of loops like coils in a heater core.   The end of each loop was hooked to a brass manifold, which was connected to pump, which was connected  to the water heater in the garage.  All the water moved between the two buildings through triple-insulated underground pipes that pretty much eliminated any heat loss during the transfer time.

As the hot water passed through the tubing inside the concrete, the loops radiated (or gave off) heat energy from the hot water.    This had the effect of warming the concrete pad, which retained the heat energy pretty well.  This was due to the fact that the bottom of the pad was sitting on insulation, and the top of the pad was surrounded by the insulated walls and roof of the shop building.   The thermostat cycled on and off as needed to keep the air temperature in the room at a consistent level, and was so quiet that I never knew when it was running.

There was no need for any sheet metal ducting, air filtration, or even a fan to circulate the heat.  All of those items are required for a typical central heating system, but were unnecessary with the radiant floor system.   When the thermostat called for heat, hot water was pulled from the garage water heater into the shop floor, while the older, cooler water was pushed back to the garage to be re-heated.  The same water was used over and over because it was a “closed-loop” system.  An “open-loop” system would have incorporated fresh water into the system but would also have required a permit to dump the water into the environment, so we chose the “closed-loop” option.  There were no chemicals added to the system, so the same water that circulated through the pex tubing could become bath water, washing machine water, or used for any other hot water purpose in the house.

The cost of the energy to heat the building was so minimal that I hardly noticed it, because it was basically just the extra natural gas used in the water heater.   My guess on the incremental cost for heating the shop building would be $10-20/month, because a lot of energy is already wasted in every water heater just keeping the water hot all the time, even when you are not using it, like at night.  I could tell that we were using the water heater more when the weather turned cold, and the gas bill went up a little because the slab of concrete had to be fully heated; however, once it was heated I could not tell any extra usage through the winter.   The gas bill went down a little in the spring when I turned off the radiant heat, but not by much.  Overall, I would say the cost of the gas and power to run the electric pump was significantly less than I would have spent with a gas furnace.

We sold that house a few years later and moved across the country, but we strongly recommend to everyone that they consider radiant heating in their home.  If I ever build another home or other building, it will have radiant floor heating.   My wife and I really enjoyed it.

If you want to pamper yourself or your loved ones with a heated flooring system, give us a call or send us a note through our on-line contact form.  We would be glad to explain the options available to you.  Remember: Be wiser, call Kaiser!