We can Learn a Valuable Lesson from a Simple Supply Register

HVAC supply grill

A standard HVAC supply register or grill or cover… . What do you call them?

You have probably seen these before. Look up at the ceiling and you will see these. You know them as HVAC supply system register sor as a supply grill. There are two pictures here because this one has a problem it is loose and the foam gasket has pushed the register away from a tight fit with the sheetrock. This gap makes a nice hole for your conditioned air to leak out of the house.

HVAC supply grill not fitted properly. Gasket has pushed open a gap

This supply register has a problem. It does not make a well sealed connection to the opening in the sheetrock. This provides an air leak passage.

Now this grill here is on a side wall so air leaks here would be escaping into the stud wall and out into the attic space through joints between studs and the top plate. You pay for all that conditioned air you are heating in the winter months that heated air is floating up and floating out into your attic.

Then in the cooling season, you don’t really want all that hot humid  air drifting in  through the ceiling in the summer as your cool air leaks out around the sills and the lower reaches of your home. Your conditioned cooled air leaking out at the slab level of the house creates the low pressure at the ceiling level. Air leakage requires a pressure differential and pathways to actually leak, and we don’t want any extra pathways for air leaks.

This needs to be repaired. This screw needs to be resized or something inserted here to allow this screw to regain a  purchase on the fastener receptacle of the register.

Now you might wonder why this issue  ends up being talked about on an air conditioning site. Well, the world has changed and the proper performance of mechanical systems are totally intertwined with the structural components of your home that keep out air leaks and insulate your home. even solar loading is involved, how much direct  sunlight comes into your home during the summer and during the winter and what times of the day…

All of these structural issues are part of modern design of HVAC systems which call for load modeling for your home to insure that equipment installed properly matches what your home needs for maximum comfort.

Seeing homes as a system and understanding the critical interdependencies between mechanical systems and the physical structure are keys to maximizing your comfort at the best investment in energy. This concept of understanding and making design recommendations through this prism is called home performance and smart HVAC service companies  are on the forefront of making sure their customers and their pre-customers are kept abreast of the information they need, to insure they are breathing healthy air in their homes, and are comfortable.

And as building science has proved and as the concept of home performance dictates, they look at your home as a working system not just a series of mechanical devices and ducts that distribute air.

If you have any questions about air leaks and home performance and the comfort and safety of your home, ask your chosen HVAC company. If they are happy to  discuss this, well you have probably chosen well. If they  poo poo design and start to proscribe solutions by pieces of equipment; well, keep looking. You need a progressive HVAC company following the new design tenants of home performance recommended by the ACCA – the  Air Conditioning Contractors  of America.


Stu Langley

meet the author at StuLangley.com

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