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Radiant System Design

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Designing a radiant heating system and installing a radiant heating system are two entirely different processes. Because the transition from the “perfect” design to the actual field installation will undergo man changes, you will have to be able to adjust on the fly.

Consumer awareness of the benefits for radiant heating systems has increased tremendously over the last decade. You are probably already seeing more and more requests for these systems than you did in the past. To install these systems so that the consumer can really enjoy the benefits and comfort, a great deal of design and thought must be put into the design first. Unfortunately, some people will say that just about anyone can install these systems in their homes for a fraction of the cost that a true professional heating contractor would charge. After all YouTube is full of how-to videos on the subject! How hard can it be to install some plastic tubing and connect a pump to a water heater?

But what happens when this unprofessional system does not function as advertised? Who is to blame for the operation of the system? This is a problem that can occur not only when a qualified contractor did not install the system but also when a professional does not adequately understand how to design the system for themselves.

A large number of professional contractors rely on their local supplier or the manufacturer to design their radiant systems. While I don’t have a problem with this, I do have a problem with what can happen during the installation and after a job is completed!

Your local supplier has been to the manufacturer training, understands how to input the required information into a design program and provide you with a materials list and basic design. What they may not understand is the installation process and the actual field situations.

I am sure many of you have designed ducted forced-air or hot water baseboard systems while sitting in the office, only to find that while on the job your original design needed to be modified to fit into the space. You were able to make those changes and be confident that they will work, because you did the initial design and have the resources to make those changes.

What happens on that radiant floor job when you can’t get the required amount of tubing in the room because the floor joists aren’t installed “by the book”, or the customer decided to add additional cabinets to the kitchen and you lose that necessary floor space for heat? Have you ever arrived on the job and found a new wall of windows? Are you able to make the necessary changes on the job, or through your programs, and be confident in the results? You must understand the limitations of a radiant system and know what the results of heat output will be when you make a change.

On the flip side, say you don’t make any changes and the system is installed the way the local supplier specified, per manufacturer’s guidelines, and you have trouble maintaining comfortable temperatures in the space. Who will the customer blame when it doesn’t work? When you customer calls you and says that the radiant system YOU installed isn’t working to their satisfaction, what will you tell them?

Typically when this is the case, the contractor calls its supplier and says “The system you designed isn’t working”!! But the supplier has no idea how the system was installed, or if any changes in construction occurred. All they can do is tell the contractor that they followed the manufacturer’s program design and it should work. The supplier may even put the blame on the contractor and say that the system was not installed properly. The manufacturer may not be able to help at this point either.

The result is a finger-pointing battle between the contractor and the supplier – one that will probably not end easily for the contractor. What do you do?

This finger-pointing battle can be avoided with the proper training and field experience. To me field experience greatly assists in a great design. At Stack Heating & Cooling, one of our first radiant projects was our own office. We followed the manufacturer’s design for the typical system and later found out, after putting the system into operation, that we were unable to balance the heating system for perfect comfort in each room. We learned from this and now every radiant project we install is able to be balanced room by room.

I’ve been a part of the design and installation of all sizes of radiant heating systems, and have yet to install one the way it looks on paper. There is always something that comes up during the installation that needs to be modified to fit the application. However, because we have the right tools and programs for design, and because we understand the limitations of radiant systems, we are able to make the necessary changes and feel confident in the final outcome of the system.

If you are interested in getting more involved with radiant heating systems, I encourage you to reach out to the manufacturers, participate in their training programs and learn how to properly design a radiant heating system. As heating professionals, I believe that it is our responsibility, and our job, to understand every aspect of what we install and service. If we don’t we are just guessing at what we do and not giving our customers what they deserve and what we promised.

Brian Stack
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Posted In: Hydronics

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