Arkansas HVACR NewsMagazine June 2018

HVACR NewsMagazine June 2018 State National Chapter News Encapsulated Attics Keeping Your Tail Out of a Crack We Hope This article contains detailed ADVICE on how to install a HVAC system in This is especially important for AC sizing. Excessive humidity is the enemy of all construction and it is the responsibility of the AC, along with ventilation, to remove humidity. In a tight home, the tried and worn default of 1 ton of AC for each 500 square feet of home will give you a wet house with the potential and even likelihood of mold and mildew problems. Ignorance is NO Excuse!

3. Install fresh air volume according to the Manual J load. (This is already Code.) Wrightsoft software is particularly good at determining necessary fresh air according to ASHRAE standards. Of course, Wrightsoft makes that determination based on your entries. You can use defaults but the only way to be certain is to do a blower door test. 4. Install the fresh air into the system return, making sure that it is accessible for filter changing. Yes, the fresh air must be filtered. The fresh air can be installed in two ways. 4a. You can use an ERV or HRV. This is an active method and the volume and run time can be varied depending on the need or preference. 4b. You can also run an appropriately sized pipe with a changeable filer from an outside air intake to the return air. Whether you choose 4a or 4b, the intake must be screened to prevent the entry of insects, easily accessible filter, and dampered to allow for flow adjustment. 5.Equipment located in the encapsulated attic must be a heat pump, air source or geothermal, or a 90+ or better gas furnace. The issue with the gas or propane furnace is combustion and ventilation air. By sealing the attic, there is insufficient air for proper operation. A 90+ furnace brings in and exhausts air by a concentric PVC

a home with an encapsulated attic. Since it is opinion based on a patch work of code and opinion, it should probably be called an editorial. I am not a code official or mechanical engineer and do not suggest

that the following 11 items will satisfy your local code official or relieve you of the responsibility or liability to properly design and install a system; however, I do believe that this incorporates most, if not all, the good ideas that I have heard. Once again, let me say that opinions are like noses, everyone has one and you can pick the one you prefer. So, here we go-- - Unofficial Protocols For Installing HVAC Systems In Encapsulated Attics +++ 1.Run a Manual J (This is already a code requirement.) Homes that have encapsulated attics always have other significant measures to make the house tight. The contractor cannot use ANY defaults in determining the equipment size, duct size, or necessary ventilation. 2. Size equipment according to the Manual J & RS. (This is already code.)