Still Using Hand Calculations for Thermal Analysis?

Compared to construction costs, the price of a simulation is minimal, and doing the calculations by hand can result in the design being off by 50% or more. For a large building, the cost savings can be over $100,000. That’s a no-brainer, right?

When you’re doing a thermal analysis for your building, you have two choices:

  • Calculate by hand and hope it’s right.
  • Calculate with a 3D simulation and know it’s right.

While the first option may be cheaper, what will it cost in the long run?

Let’s face it. There are situations where hand calculations are sufficient. If you’re designing a single-family home, it will do just fine.

But what if you’re designing a large building with complex shapes and multiple uses? What if the temperatures inside the building are much different from those outside?

You may need to consider doing a more in-depth analysis.

Why 3D Simulation Can Make a Big Difference

Using a 3D simulation for your thermal analysis offers many benefits. Here are just a few:

  • Saves money
  • Creates a more accurate design
  • Incorporates multiple building elements into the design
  • Allows you to get closer to the target, without being too conservative
  • Includes your existing BIM models in the design
  • Insulates you from risk, documenting your due diligence

A closer look at each of these benefits reveals what they mean to you.

Saving money

As mentioned, hand calculations will likely be cheaper than a 3D simulation. But, when you reach a point where adding more insulation won’t solve your problems, you need a different solution. A 3D simulation will cost more up front. But, that cost can easily be offset with savings in the actual building itself.

Create a More Accurate Design, Incorporate Multiple Building Elements, Get Closer to the Target

When you do a detailed simulation, you don’t have to make broad assumptions that treat most rooms and walls the same. Every element of the building can be considered, giving you an accurate picture of how it will perform in real life. Let’s say you have a steel pin that’s exposed to the exterior and interior of your building. This pin can transfer heat from the outside in, or vice versa, causing your HVAC system problems, and creating a hot or cold spot in the building. With your simulation, you can consider each of these elements and address them before they’re a problem. This lets you design your HVAC system with optimal efficiency, which is the whole point of the design process. This gets you much closer to the target you’re trying to hit, without being overly conservative.

Include Your Existing BIM Model in the Design

If you don’t want to go to the trouble of creating a new model from scratch, here’s good news. If you created a BIM model when you designed the building, you can incorporate that model into your simulation. This saves a lot of work and allows you to use something that was already making your life easier. With more and more designers using BIM models, chances are your building will have one.

Insulate Yourself From Risk

Unfortunately, things sometimes go wrong. A project turns into a disaster, and someone has to take the blame. If the building is done and things aren’t working right, it can cost a lot of money to fix … sometimes hundreds of thousands or even millions of dollars. Take the case of a hospital. If the HVAC system isn’t properly designed, condensation can build up in the hospital windows.This seems like a minor problem but can lead to contamination and patient infections – definitely a major issue for any hospital. If you do a detailed 3D simulation on your building, you’ve documented that you did your due diligence. If the system isn’t doing its job, it’s not because you didn’t do yours.


Beyond what we’ve covered here, there are many more reasons you should consider doing a 3D simulation. When it comes time to do a thermal analysis on your building, consider the long-range cost associated with your chosen method, and whether you’re willing to pay it. Maya HTT provides multiple software programs for you to do thermal analyses of your buildings. They also provide consulting services with professionals that are experienced in 3D simulations. To learn how Maya can help you, visit our building engineering page.

Subscribe to our newsletter