Arkansas HVACR NewsMagazine November 2024

HVACR NewsMagazine November 2024 Tech News

Everything Else is Secondary Popularly, HVAC sizing is done by square footage. Size of the home divided by a number. 500, 600, 700 etc. When you factor in changeouts, most jobs seldom see a real load calculation done. If a real load calc is done, you click on a box that describes Envelope Leakage as Average in the middle, and Leaky, or Semi Leaky on one side and Semi Tight and Tight on the other side. Again, most of the time we look at the construction era and guess. Pier and Beam- Leaky. Slab on grade with a foam / air barrier as tight. Everything else is in the middle somewhere. Let us take a moment to see how guessing at air tightness affects our work. Yes, municipalities require load calculations and seldom are they reviewed. Calculations are collected and filed so if a consumer has a complaint the municipality is covered. The contractor is responsible for the information in the load calculation.

training contractors in air side performance. What are the tools we are talking about? To answer the tool question, we need to address a long-standing issue. Ever since homes have been conditioned to battle the environment, there has been a rift between the home building sector and HVAC industry. Each industry needs the other, but, when things go wrong, finger pointing becomes the plague. The HVAC industry expects the housing industry to listen to needs, and the housing sector expects everything to be pretty with no space infringements. Never mind that codes early on required a percentage of floor space set aside for mechanical equipment installation. As a result, the HVAC industry leaves it up to the construction industry to build correctly and thinks building science is for just the construction guys. HVAC guys will handle the air side of things. All too often there are failures on both sides. There is progress being made on both sides of the aisle. The HVAC community is broadening awareness, while builders like Matt Risinger of the “Build Show” has been paying more attention to the HVAC portion of the construction industry than some HVAC contractors. If you are talking about HVAC airside performance, you are talking thermometers, hygrometers, flow hoods, hot wire anemometers, manometers, and ammeters. When you talk about building science , we investigate blower doors along with most all the air side tools. We will look at the most common air flow device first. We will discover how this air flow measurement should be secondary.

“You are guessing if you are not testing” is a phrase popularized by a leading company,