Bard Wall Mount AC and HP Units: Energy Efficiency Standards Revisited

The one question I’m always asked is whether the Bard wall mount unit meets the minimum 13.0 SEER efficiency required by the Florida Building Code and International Mechanical Code?

The short answer is no, but that is only because the unit is no longer rated in SEER, but rather the commercial standard of EER. So the real short answer is YES, it meets the code requirements for minimum energy efficiency; rather than SEER, it’s rated as Single Packaged Vertical Unit (SPVU) AHRI-390 classification meeting a minimum 9.00 EER. Needless to say, after years of the equipment being rated in SEER, we frequently need to provide a more detailed explanation and documentation to customers who are unable to locate a SEER rating for a Bard wall mount unit. It not only confuses customers who are unaware of the change in the rating system of a Bard wall mount it confuses other professionals and building reviewers/inspectors. Starting with ASHRAE 90.1-2004, a new SPVU classification was created for Bard wall mount units. Beginning with 90.1-2004 and continuing with 90.1-2007 and 90.1-2010, Bard units’ minimum energy efficiency is listed in AHRAE 90.1 Table 6.8.1D as 9.00 EER. In 2006 the U.S. Department of Energy (DOE) ruled that SPVU units were no longer to be certified to the residential 13.0 SEER standard, but rather the Energy Policy Act of 2005 (EPACT) commercial EER ratings, thus the new standard for energy efficiency of a Bard wall mount unit was 9.00 EER. The International Code Council’s International Energy Conservation Code (IECC) followed suit and the published minimum energy efficiency standards for Bard wall mounts that were adopted nationwide as 9.00 EER.

As we know, Florida has a separate code that generally adopts much of the ASHRAE standards and as with IECC, Florida also adopted the minimum EER rating of Bard wall mounts. Table 503.2.3(3) in the 2010 Florida Building Code Energy Efficiency lists the minimum EER for SPVU, both air conditioner (SPVUAC) and heat pumps (SPVUHP), both being 9.00 EER. Although all of Bard’s products meet the minimum required 9.00 EER, Bard has additional wall mount and indoor mount package units that far exceed this minimum efficiency. These higher efficiency units are often selected by energy conscience customers and or an HVAC efficiency upgrade that needs to pass a buiding’s Energy Calculations to meet overall building efficiency. Bard has a complete line of wall mount products that include ratings up to 12.00 EER, a 33% efficiency improvement over the minimum requirement. Additionally, Bard has a product line of two stage compressors which include an Integrated Part Load Value (IPLV) rating. The IPLV takes into account the improved energy efficiency at part load (1st stage cooling). As we know, building load calculations are prepared based on “peak load” conditions, however a building is typically operating under part load (non-peak conditions) most of the time. The benefit of selecting a unit with a reduced part load performance (1st stage) is improved energy efficiency associated with a reduction in energy use to meet the non-peak loads.

These two stage compressor wall mount units also provide an improvement over standard single stage compressors as run time is longer during part load conditions which improves dehumidification, a great benefit here in Florida. Another lesser known method of increasing a standard unit’s efficiency is the use of an Energy Recovery Ventilator (ERV). An ERV provides the required ventilation to meet air quality standards associated with ASHRAE 62.1 and the Florida Building Code, but it has the added benefit of reducing the ventilation load with an air-to-air heat exchanger. Rather than wasting energy by discharging conditioned exhaust air to the exterior, a rotary, total enthalpy heat exchanger transfers energy by pre-conditioning incoming fresh air by transferring this energy before being exhausted. The Air Conditioning Heating and Refrigeration Institute (AHRI) acknowledged the improved energy efficiency of an HVAC unit utilizing an ERV and in 2011 published Guideline V, Calculating the Energy Efficiency of ERV and its Effect on Efficiency and Sizing of Building HVAC systems. In short, a reduction in building load as a result of utilizing ERV leads to a reduction in required HVAC capacity, allowing for a reduction in equipment size. This can have a dramatic impact on energy use and HVAC sizing, especially for high occupancy buildings such as schools and assembly buildings. We often find that by utilizing an ERV in a typical classroom environment one can reduce unit sizing by at least ½ ton to 1.0 ton, which represents 225 CFM to 450 CFM respectively at 95F/78WB outdoor design conditions. It’s important to note that ASHRAE has recently adopted ASHRAE 90.1 – 2013, which increases the SVPU cooling mode minimum efficiency to 10.0 EER (heating mode efficiency remains at 3.0 COP for heat pumps). The Department of Energy (DOE) has not yet established a date for adoption of ASHRAE 90.1-2013, however it is anticipated that adoption will take place in the near future. Please keep this in mind when designing buildings and equipment that will require this new 10.0 EER minimum energy efficiency for your next project.

About the author: Frank Suranyi, is the Engineered Products Manager at AccuAir Inc.

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