Growers Supply

Radiant Heating Systems Webinar

Questions & Answers

  1. Do you have any customers using radiant heat with an electric furnace and a windmill?
    Right now, I don't know of any customers who are using a windmill to help supply power to a radiant heating system. I do have customers that are using solar power. They usually plumb their systems with a tankless boiler as a backup. So, it could definitely work in theory, I just don't have any specific examples.
  2. Will hydronic heating provide all of the heating needs for a greenhouse in the winter?
    A properly sized system can provide all of the heat you would need. There are a few factors to consider in terms of your glazing, the temperature you would like to maintain and how much tubing we put in the slab below, but it is definitely a good option. A lot of my customers still keep a Modine heater for supplemental heat or as a backup. We can help you design a system for your specific application.
  3. Can you use multiple boilers in a system?
    Yes, multiple boilers are common. You can piggyback them if you need higher water temperatures or you can set it up as a backup system.
  4. I would like to match hydronic heating needs with hydroponic growing. Is that possible?
    It's possible. You can use the hot water from the boiler to warm the water in your hydroponic system.
  5. Have you ever set up a dog kennel with a radiant heating system?
    Yes and radiant heat is a great option for this application. Dogs really enjoy lying on the heated slab.

Radiant In-Floor Heating

  1. What is the recommended loop length/spacing?
    It depends on the building. We use Pex-B Oxygen Barrier Pipe that comes in a few different sizes. Usually, the 1/2" tube will go a maximum of 300' and the 5/8" will go 400', but it really depends on the application.
    1/2" - 300' max
    5/8" - 400' max
    3/4" - 500' max
    Spacing is dependent on the application and can be 6", 8", 12" or 15".
  2. Do you need insulation under the concrete?
    Yes, in order to prevent heat transfer loss you need insulation under the concrete. We recommend TekFoil™ Reflective Insulation. In northern climates, 2" foam board is recommended under the TekFoil.
  3. Is there any building size too small to use the radiant heat system?
    No. This system will work for spaces as small as 400 sq. ft. and as large as 40,000 sq. ft. There is no limit; your components will just get smaller or larger depending on the size of the system you will be using.
  4. What is the most efficient pex size in a slab system for residential use?
    For a slab system in residential use, we recommend 1/2" pex. The only residential application where larger pex might be necessary is for very large square footage.
  5. I have a 24' by 48' greenhouse from Growers Supply; is it worth doing this system or do I need something else?
    There are a lot of benefits to using a radiant heating system. It is very efficient, very controllable and you get even results. Putting in a radiant heating system is a little more involved than just hanging a heater, but in the long run you will end up saving more in fuel costs. A radiant heating system is the best way to go.
  6. How does the efficiency compare to infrared tube radiant systems?
    A tube heater system is another unit that is typically used in slab applications, but it is a little bit different. You are supplying infrared heat to a thermal mass, but efficiency is better in radiant heating because there are no cool spots. A tube heater is generally very hot where the gas is supplied but as you run down the tube that heat is diminished by about 10° per running foot.
  7. Can one system heat two floors?
    Yes, one system can be used to heat two floors.
  8. If the system is installed on the first floor, will it heat the basement?
    No. The radiant heat might help to raise the ambient temperature in the basement by a few degrees, but you will need another heat source, like a space heater, to supplement it.
  9. What is the difference between pex and Pex-al-Pex?
    Pex-al-Pex is pex with an aluminum liner, then another layer of pex, which allows Pex-al-Pex to bend and stay in form. Pex does not have an aluminum liner, so it does not retain its shape when bent.


  1. How do I determine BTU requirements?
    BTU requirements are calculated using several factors. Building size, location and application are just a few examples. We have a software program that can help you figure out the BTU requirements for your specific project.
  2. Do electric boilers work for large installations?
    Yes, they will work for large installations. Our largest electric boiler has a BTU output of 122,868 BTUs, however, it requires three 70-amp breakers.
  3. What is the required maintenance for a boiler?
    Boiler maintenance is easy. On an as-needed basis you can use a descaler kit to remove lime, water scale and rust buildup. By using the isolation valves on your system's manifold, you can easily use this kit to clean out the heat exchanger in your boiler. The isolation valves are attached to the boiler. These should be serviced every 6 to 12 months.

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