The Dangers of Like-for-Like Tonnage

Alex Meaney from Wrightsoft joins us to talk about Manual J and S. He also discusses how load calculations and equipment selection apply to real-world situations where contractors are tempted to replace “like-for-like.”

Load calculations have been a staple of new installations, but they are becoming important in retrofits as well. We consult Manual J when we do load calculations for residential HVAC designs. We determine where the heat loads are coming from to see how equipment can address those heat loads; in heating, we want to replace heat losses. The technicians who do load calculations also tend to get more customers and have better outcomes because they show additional care and can educate customers.

We must also be diligent and check our mistakes in calculations AFTER we work on them. In general, most load calculations will NOT determine that upsizing is the right solution.

Then, we use our Manual J calculations to use Manual S for equipment selection. When we propose solutions for retrofit installations, we should quote the customer for our recommended solution and like-for-like tonnage. You could also talk with the customers about ways to adjust the heat load; just don't tell them they're wrong, even if they are. It also helps to be straightforward about the health and dehumidification benefits of the best solution versus the like-for-like retrofit option.

Alex and Bryan also discuss:

  • When customers are comfortable with oversized systems
  • S.W.A.G. in system design
  • Looking at math AND customer demands
  • Uneducated homeowners and what they do know
  • Don't put thermostats in the hallway
  • Moisture issues, latent capacity, and dehumidification
  • Commissioning
  • “One trip, close” sales
  • Talking to customers about sales and quotes
  • “It's not time wasted; it's time invested”
  • Making time for load calculations and consultation

Use the offer code POD2019 for a great discount on Wrightsoft products at

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10/4/19 at 06:47 PM

Super episode! Thanks Bryan and Alex.




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