Comcheck versus Manual J

Author is Jobe Leonard with Rescheck.info affiliate Reschexpert blog.  He enjoys creating Comchecks and Manual J heat loss for others as a service.

Jobe Leonard Rescheck.info

Comcheck versus Manual J

This edition of the Reschexpert blog we want to discuss two energy reports without the word Rescheck in them at all. These are two of the most important home energy reports in all of the construction industry and each do unique calculations. By comparing a Comcheck report and a Manual J heat loss and gain, we hope to answer many questions for our loyal readers. Thanks for tuning into this version of the Reschexpert blog as we put Comcheck vs Manual J.

Every home built has it’s own energy needs. These heating and cooling loads are determined by the climate zone where it is being built, how the home is designed, the amount of insulation used, the hvac system and appliances, and the actual craftsman that construct the house itself. Manual J is a report that measures the heat loss and heat gain of a structure. This tells you how much heat in BTUs will be needed to heat the structure and how much cooling will be needed to cool the structure. This is the nationally recognized standard for producing HVAC loads for single family homes, condos, townhomes, manufactured houses, and smaller multi unit structures. Some advantage of Manual J are below:

Uses Summer Outdoor Temps from historical local climate data

Uses Winter Outdoor Temps from historical local climate data

Uses the elevation of the area near the jobsite

Uses humidity data from historical local climate data

Includes roof, wall, window, door, foundation construction data

Uses the number of occupants expected to be in the home

Typically used in residential applications with some adaptations for smaller commercial structures

Can be calculated with specialized software, by hand, or using custom spreadsheets or calculators

Takes into account appliances and the loads they create

Using all this data and plenty more the Manual J calculates a custom heat gain and heat loss for your new home construction, addition, or home alteration. This makes the Manual J a very powerful component to any home energy audit and one of the top home energy reports available on the market today.

Now let’s look at the competitor. Comcheck, can be used for any type of commercial structure. Also multifamily building that are more than 3 stories above grade can use a Comcheck report as well. Comcheck is created as a 10-15 page report that compares a structures insulation envelope, interior lighting, exterior lighting, and mechanical system to an energy code. ASHRAE, IECC, and State specific are the most commonly used Energy Codes in Comcheck, however, there are many more. To calculate a Comcheck report you would have the option of two different energy audit softwares, Comcheck Web and Comcheck Desktop. The advantages of using Comcheck for energy reporting on your commercial structure are as follows:

You can create a Comcheck offline using Comcheck Desktop

A Comcheck can be created online using Comcheck Web

Comcheck can be used all over the United States and some areas of Canada.

Climate data is built into Comcheck Web and Comcheck Desktop

Specific city and state locations are built into Comcheck Web and Comcheck Desktop

Comcheck includes pre-set criteria for many different types of commercial structures

Comcheck Web and Comcheck Desktop are free and provided by the Department of Energy

Comcheck has 27 different energy codes built in and is always being updated

Comcheck puts all the players in a commercial construction project on the same page when planning out a buildings energy efficiency, insulation, lighting, and components

Comcheck is fast and accepted nationwide

Comcheck has a lot of advantages, and is one of my favorite energy auditing softwares. It can take a 110 level skyrise building and condense the energy efficiency of the structure into a 15-20 page report that is easy to understand and implement for everyone involved in the project.

Overall, Comcheck and Manual J can be compared to each other, but they can typically not be interchanged on most projects. You might have a Comcheck and a Manual J needed on a project. It would be very uncommon for a building inspector to give you the option to use a Comcheck in place of a Manual J, or vice versa. That is because they handle two different aspects of energy efficiency. The Comcheck handles a commercial buildings envelope, lighting, and mechanical. The Manual J is primarily used on residential structures and measures a structure’s heat loss and heat gain. As to the winner of the Comcheck vs Manual J battle I am going to tip my hat to Comcheck. Comcheck is a free software and many times Manual J is not. When it comes to access to energy efficiency softwares I tend to prefer the ones that are free to try. Many instances a building department will require a certain software package for Manual J that costs thousands of dollars to buy the software. I think this is unfair. Since Comcheck is free and updated routinely I will give it the win. Allow people to practice energy efficiency techniques on free software is what makes the Department of Energy and Pacific Northwest Laboratory’s Comcheck Software very powerful.

At Rescheck.info we offer both Comcheck and Manual J. If you have a commercial structure in need of a Comcheck or a residential structure that needs a Manual J heat loss the process is the same. Email us a PDF of plans, jobsite address, and square footage and we will get your Comcheck or Manual J taken care of. Thank you so much for reading our Comcheck blog post and Manual J blog post as we put these two key players in the energy auditing market head to head.