TO  INSTALL - OR  NOT  TO  INSTALL -  RADIANT  CEILING  CABLE?

That is indeed the question.

In conjunction with Frank McShane, owner of Heat Products (manufacturer of radiant ceiling cable) this is our response to someone’s reasons not to install a radiant ceiling cable system.

• Application temperatures are restricted to above forty-five degrees.
• I will assume that ‘application temperatures’ are referring to the temperature at the time of installation. Radiant ceiling cable can be installed in any temperature suitable for a laborer to perform a task of any sort. The material used to cover the cable/ceiling is a water-based material that must be kept from freezing. All of our high-end residential projects had the electric heat installed towards the tail end of the project after the painters finished. We also found this true with radiant ceiling projects. The electrician does his rough-in, and when the plasters are ready to start the cable gets installed.

• All areas must be free of dust, dirt, oil, grease, or texture.
• This is not a true statement. When applying the spacer strips with an adhesive the area that the strip is attached to should be wiped down. This has never been a problem. But you can use other methods of attachment such as staples or nails. On some of our more prominent installations, Water Tower Place and The John Hancock Building, we attached the spacer strips right to the concrete slab using an adhesive with ZERO problems.
• Application is limited to interior ceilings only, usually over ½” gypsum wallboard.
• “…limited to interior ceilings…?” I take that to be the opposite of exterior ceilings? I relish the chance to respond to the sublime but refuse to rationalize the ridiculous. Most installations are right to the slab. We have only have few restrictions as to what the product should not be installed on to, such as tile, wood, or metal.

• Installation strip affixed to ceiling with contact cement.
• That is one method for attaching the spacer strips but not the only one as mentioned earlier. Other methods include a Dow adhesive with a much friendlier MSDS than contact cement is the most common. Staples or nails have been used and are an acceptable method per the manufacturer.
• Adequate ventilation is required for drying in any season.
• Adequate ventilation is needed for breathing, and for the drying of paint.  Bottom line, we do not need any “special” ventilation.
• No responsibility is implied or assumed for design, application, or adequacy of heat.
• No more heat (watts) will be needed other than what was originally designed using other types of electric resistance heat. A watt will still be 3.413 BTU/H whether it is in a finned tube baseboard element or a duct heater. Where an argument can be made is whether or not the application of a particular style of heater is correct for a given space. That is an arena which radiant ceiling cable has only one worthy opponent and baseboard or wall heaters are not it. I will give a more detailed explanation in my summary.

• Resistance heat has a very slow recovery rate.
• This one takes the cake. First of all, any heater that uses electricity as its energy source is a resistance heater. That means electric convectors, wall heaters, unit heaters, floor heat, etc.

Let us compare “recovery rate”.

Electric finned tube convectors for this type of installation are most often controlled by one of two methods.

1. Interfaced with a fan-powered system that has a low voltage thermostat on an interior wall centrally located in the space.
2. Low voltage thermostat located on an interior wall dedicated to the baseboard.

Either one of these two methods have a surprisingly long “recovery rate”. The baseboard which is installed under some glass at the curtain wall with the thermostat located on an interior wall approximately 10’ from the baseboard and the exterior wall. It is  -10°F outside with a 20MPH wind. The ambient temperature is 71°F at the thermostat, which is set for 70°F. The temperature at the glass (within one foot) is considerably colder by let’s say 4°F. By the time that cold radiates to the thermostat and we get contact closure for the baseboard to energize we may have lost another degree or two at the curtain wall. The baseboard will take a minute or two to get to its rated output. The baseboard will be heating the air and slowly make its way toward the interior of the space and finally affect a temperature rise at the thermostat. That is a “slow recovery rate”.

The radiant ceiling cable system becomes effective as soon as the ceiling temperature becomes greater than the ambient or the surface temperatures of objects in the same vicinity. Plus, there is no migration delay. Once that ceiling has achieved that ‘DT’ it is transferring energy. That is an extremely fast recovery rate. This system, like our floor heat systems, amplifies the science of ergonomics, or better stated, tenant comfort.

Summary

I am in no way bad mouthing electric baseboard heat. I believe that no other manufacturer’s rep has sold more electric fin tube than Trans Energy in the country the last 20 years. It is our bread and butter. Electric baseboard is an effective means of heating. In the above case it is not the heater that is the problem, but rather the control. Any perimeter resistance heat should be proportionally controlled based on the BTU loss/gain at the perimeter.

A gentleman I once worked for had the reputation of being an expert with respect to electric resistance heat. His name was Larry Morgan. We would discuss electric heating application for hours on end. One of our discussions led to the question of what is the perfect heating system.  Larry’s response was that every square foot of every surface in the space should radiate heat. That would include the floor, ceiling and walls. Spreading out the heat is key to people comfort. Radiant ceiling cable offers a large heating surface to warm the space and people. Some people have commented that the radiant ceiling system, once under it, feels like walking from shade to being in the sun.

The radiation theorem ‘Q=s A (T1  - T2)4⁴’ simple states that heat transfer in BTU/H: (Q) equals emissivity factor (s) times the area in square feet (A) times the absolute surface temperature differences in degrees Rankin with both temperatures raised to the forth power. This is as opposed to the convection theorem, which only raises the convection surfaces temperature differences to the first power. Simply stated the radiant heat is much more efficient than convection.

Bottom line about radiant ceiling cable is as follows:

1. It makes absolutely no noise.
2. It takes up no floor space.
3. The heater is maintenance free.
4. It more comfortable that perimeter convection because the heat is spread out.

We, Trans Energy Systems, have prided ourselves in knowing electric heating systems. We know application. We know that for high-rise, high-end residential buildings, the radiant ceiling cable system is the right application.

Trans Energy IR Series infrared heaters can be used for spot or localized area heating or total heating. The very nature of infrared radiation permits the heaters to be used in areas where convection or fan-forced heaters would be completely ineffective.  For a full booklet of our Radiant Ceiling Heaters, please download here.

Mark A. Prete