Arkansas HVACR NewsMagazine January 2024

HVACR NewsMagazine January 2024

Tech News

Dehumidifiers and Install Application As the housing stock across the US is improved by Code application on new construction and general upgrades to existing structures, it becomes necessary to review the necessity of adding dehumidification equipment to supplement or supplant the HVAC equipment installed. Homes become less dependent upon mechanical means to keep the environment at a stable temperature for occupation, the less the HVAC equipment will influence latent loads. To say it another way, the HVAC system run time is decreased due to better insulation and construction methods so the left over latent loads will have to be maintained by other means. Washing clothes, showering, cooking or just breathing are often overlooked latent internal loads. Comfort is ruled by latent loads and temperature alone will miss the mark most of the time. A major roadblock to making corrective changes to any system is convincing to occupant something is wrong. Occupants learn a temperature setting under the guise of comfort. They adjust the temperature where they believe they are comfortable. That setting may be 70 degrees or lower just to feel somewhat cool. Hidden is the fact that humidity levels of above 60% drives consumers to lower their thermostat. Envelope leakage is likely on homes built prior to 2007. You must carry the tools to demonstrate the mechanics of air and the necessity for change. Today’s new homes suffer the same settings, but it is likely due to the fact the system lacks the capacity or run time to mitigate humidity from internal loads

or may be oversized. Some companies have purchased portable dehumidifiers to give the consumer the opportunity to witness the improvement. The contractor delivers from a small pool of machines depending upon the application. But there are drawbacks you must be prepared to overcome. There will be customers that want “ just get by ” . They will beat it down to the big box, let a sales person dictate the size and likely will be unhappy with the results. Or you can explain at the outset that whole home dehumidifiers are longer lasting and more effective in most situations and that you have the tools to make the selection for them. The first hurdle is to make sure the HVAC system will handle latent loads. More often than one might expect, high performance equipment may save energy, but leave humidity behind. Don’t be tempted to oversize the equipment to address latent capacity. The fact is exacerbated with newer homes because the space is more efficient at keeping ambient temperatures out of the envelope. The three ton system below demonstrates adjusted capacity has little to do with the nominal tonnage the equipment is marketed by. This phenomenon is not brand specific. All brands suffer capacity as efficiency is increased. Manufacturers use more mass (heat transfer material) with minimal compressor capacity to save energy.