Symposium Addresses Energy Efficiency and Moisture Control in Florida

The Florida Department of Community Affairs hosted a one-day symposium, Energy Efficiency and Moisture Control in Florida Homes, on February 28 at the Doubletree Hotel in Tampa, Fla. The purpose of the event was to identify the relationship of sensible heat load and air-conditioning systems to moisture control in the Florida climate.

It was also to discuss the concerns and in particular--from the fenestration community's standpoint--how these concerns will affect the continued effort to market and sell low solar heat gain coefficient (SHGC) glazing in Florida.
The symposium presenters discussed:

  • The effect of heat gain through windows on sensible heat loads;
  • Moisture control in Florida homes and its relationship to sensible heat loads;
  • Engineering and manufacturing latent heat removal by residential air conditioning systems;
  • Field applications of advanced residential air conditioning systems;
  • Residential air conditioning systems service industry and its competency to implement effective moisture control strategies; and
  • The critical importance of considering the glazing package when sizing air conditioning units.

Rick Dixon, chief of staff for the Florida Building Commission, noted that Florida created air infiltration standards to control the moisture flow and humidity to air handling units, primarily to reduce health risks and improve indoor air quality. These provisions were to prevent biologicals such as mold spores, dust mites, etc. from obtaining a foothold in structures built in high humidity regions such as peninsular Florida and the Gulf Coast, according to Dick Wilhelm, president of the Fenestration Manufacturers Association (FMA).

Dixon noted that the purpose of the symposium is "to assess the risk to indoor air quality, identify technology to counter that risk and develop a problem statement to identify actions and strategies to address such risk."
The topic is of importance to the fenestration industry because the FMA had sponsored numerous amendments in late 2006 to place key International Energy Conservation Code (IECC) provisions into the Florida Energy Code. These amendments were soundly defeated in the Energy TAC by the heating, air conditioning and ventilation community (HVAC) as well as the Florida Solar Energy Center (FSAC).

FMA was informed that the continued push to introduce energy-efficient windows into Florida will have a detrimental effect on the SEER 13 HVAC systems, indoor air quality and will help promote mold in Florida homes.
Chris Mathis, building science consultant with MC² served as the spokesman representing the fenestration industry's position.

A few of the points made during presentations:

  • The optimal comfort zone in the continental United States is 65 percent relative humidity at 75 degrees Fahrenheit. This matrix is recommended to inhibit mold, bacteria and mites;
  • It has been discovered that Florida and the Gulf Coast, due to high humidity, requires 55 percent relative humidity to achieve the same optimal comfort zone;
  • Bigger is better when it comes to air conditioning units does not hold for Florida or the Gulf Coast;
  • Retrofit of homes with new window packages may require the use of variable speed fans added to existing air conditioning units;
  • If air conditioning units are consistently oversized and the glazing is changed to low SHGC, the mold problem is compounded;
  • The HVAC community would like to see Florida require variable speed fans added to existing air conditioners; and
  • Windows are the key to sizing the HVAC system.
According to the FMA, the HVAC community would like to see:
  • A phase in of low SHGC glazing requirements;
  • Air conditioning contractors, installers and builders to be required to take a CILB course to educate them on matching the glazing to the air conditioning and heating unit;
  • Would like to maintain a performance-based code as Florida currently has;
  • Reconfigure Manual J; and
  • Demonstrate to the builder and homeowner the advantage of sizing air conditioning equipment based on low SHGC glazing package.

Arlene Stewart, president of AZS Consulting Inc. explains the several paradigm shifts occurring in building in Florida.
"FMA is pushing for a 0.4 SHGC in the prescriptive, with a 0.5 SHGC maximum in trade offs. The HVAC contractors association is concerned that there are too many shifts taking place at one time and there isn't nearly enough training available to teach them how to handle it. And even if they did, many contractors don't believe it," she continues. "Essentially, the old technologies don't have the moisture removal capacity and the technologies that do are more expensive and not necessarily routinely stocked in Florida."

Trane, Carrier and Lennox all indicated at the symposium that they had products to handle the humidity, even though they were expensive.

"The correct equipment hasn't trickled down to the guy in the field yet," Stewart adds.

The symposium concluded with two major recommendations:

  • Standardize design considerations for sizing air conditioning equipment including mechanical plans for residential construction; and
  • Create continuing educational courses for HVAC community, builders, glazing contractors and plans review.

The FMA says it will continue to remain involved in the course development. The association will be soliciting support from members to assist the DCA in course development.

"All in all, the meeting went very well for the window manufacturers because it was more a symposium about how to make the transition, rather than '… what are we going to do'," says Stewart.

For specific details on the symposium, visit http://consensus.fsu.edu.


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