The Manual J Calculation: Math That Matters To You - MoreVent Skip to content

The Manual J Calculation: Math That Matters To You



You should never invest in a new air conditioning system without having a manual J calculation done. In fact, it’s one of the requirements specified by the EPA, as well as EnergyStar.gov. Before a company even offers you options, they should perform this calculation to ensure that you’re getting the right size system in your home.
The problem with an oversized system

An oversized air conditioner usually results in an uncomfortable environment that tends to be extremely clammy. The air conditioner isn’t able to run its designed time to remove all the moisture and humidity from the home. Clients tend to turn their air conditioner down several degrees to make up for that clammy feeling in their house. That ultimately results in higher utility usage, more repairs, and systems that will have to be prematurely replaced.

Ensuring the right sized system

Before MoreVent ever designs options for a client, our comfort advisors are required to perform a manual J calculation. A manual J calculation can take anywhere from sixty to ninety minutes to measure your entire home and all your ductwork. This ensures that the options that are designed are not only going to fit your house, but they’re going to perform to the system’s design parameters.

Some companies cut corners

It takes time to do things the right way. There’s an expense to having a team member out to a home for sixty to ninety minutes to gather all of that data and crunch all the numbers.

In a lot of cases, companies come in and basically put in the same system that a client had previously. Well, that’s not always the best decision, because a manual j calculation might not have been completed the first time around.

MoreVent takes it a step further

After MoreVent does your manual J calculation, all that data comes back to our office. We have an in-house engineer who double checks all the calculations to ensure that what our comfort advisor provided you was actually the right solution.

We want to make sure your system is the perfect fit for your home from an energy and efficiency perspective, so it will provide you a comfortable environment.

If you want to do it right the first time around, give us a call and we will make sure you and your home are taken care of. We can be reached at 610-444-3333.