h2x: The Smartest Hevacomp Replacement for Design Engineers

On January 1st, 2026, Bentley Systems formally ended support for Hevacomp, their legacy building services design platform. Although historically slow and clunky, Hevacomp was widely used by design engineers reluctant to make the switch to a modern platform. After January 1st, though, designers were essentially forced to search for a replacement platform. The search for a credible Hevacomp alternative has led most engineers to evaluate two main options.

There are two potential successors to Hevacomp: OpenBuildings Designer and h2x. While both platforms are designed to support building services engineers and promise accurate calculations and informed decision-making capabilities, they are radically different. For design engineers, these differences are significant and will impact the extent to which and how they are able to use either platform to boost productivity and profitability.

Read on for a clear and concise comparison that will enable design engineers to see critical differences between OpenBuildings Designer and h2x.

h2x vs OpenBuildings Designer: Quick Comparison

h2x: Created By Engineers, For Engineers

Understanding how a MEP design software platform was designed and built will help design engineers assess its overall functionality. A software platform’s “origin story” – or the conditions that prompted its creation – can tell a lot about how useful it might be in its current iteration.

OpenBuildings Designer was not originally created to perform advanced mechanical calculations. Its scope included modeling and documentation capabilities, and it was positioned as a competitor to Revit, another popular design program. Over time, mechanical tools were added to OpenBuildings to make it more functional.

h2x was designed by engineers, for engineers. Its origin story began with the frustrations of an engineer who had been using spreadsheets and other time-consuming processes and cumbersome platforms to complete complex design projects. Hevacomp in particular can yield a slow, tedious user experience, and was known to stymie engineers who needed to reconcile architectural changes. For example, Hevacomp required many calculations to be entered manually, which increased the risk of errors and necessitated multiple quality checkpoints. Engineers needed a platform that was fast, reliable, accurate, and intended to work with Revit while not competing with it. h2x was created by engineers to offer engineering-grade, accurate calculations and to support the unique design processes of engineers as they interface with architects and clients. From its origin, it was meant to be a clean, modern, calculation-driven platform that fit alongside Revit like a glove.

OpenBuildings Designer: A steep learning curve

A program that strives to be everything to everyone can actually slow down users and impede the design process. Many mechanical engineers who use OpenBuildings Designer, for example, will find several tools, menus, and features to be simply irrelevant to their role. Understanding all of the available tools and narrowing down the specific tools that are relevant and useful means that new users need weeks, and in some cases months, to achieve even basic efficiency with a program. This is compounded when firms add staff, as each new team member faces a lengthy onboarding process in order to achieve even basic proficiency.

h2x: Clarity over complexity

h2x has a modern interface that is calculation centric. Engineers are not forced to navigate irrelevant architectural or structural tools. Learning how to use the platform is easier, as all of the tools are designed to be relevant and functional for engineers’ specific roles in the design process.

Read on for direct comparisons between these two programs.

Calculation Transparency and Accuracy

Besides ease of use, design engineers want a platform that they can trust to provide verified, understandable calculations. Without transparent, engineering-grade accuracy as a baseline, efficiency gains would be minimal, as engineers would need to manually check each calculation.

OpenBuildings Designer

If you were frustrated with the limitations and clunkiness of Hevacomp, you will continue to feel the pain with OpenBuildings Designer. It has inherited the slow Hevacomp calculation engine and along with it many of Hevacomp’s limitations:

• Calculations are not CIBSE-verified or transparent
• Legacy calculation methods are slower and leave more room for error
• Calculation assumptions are difficult to trace
• Inconsistent documentation leads to fragmented processes

h2x

h2x is built on fully transparent, standards-based calculations. Users can see the exact inputs, formulas, assumptions, and methodologies. The platform is updated continuously as updates are pushed instantly through the cloud. Its key advantages include:

• Full engineering transparency
• CIBSE-Verified Calculations: Industry-leading accuracy ensures compliance with global standards
• Easy-to-export calculation reports
• Audit-ready outputs for clients and regulatory bodies
• Consistent, traceable calculations across projects

The difference between these two programs can be summed up in two simple questions: What is your peace of mind worth? And how important is the accuracy of your output?

Speed, Efficiency, and Productivity

The adoption and use of a design platform should deliver significant productivity gains for engineers, who would otherwise have to complete mechanical calculations on their own. Knowing this, there are significant performance differences between OpenBuildings Designer and h2x that clearly position h2x as the superior choice.

OpenBuildings Designer

Because of its underlying legacy technology and the fact that it is not built primarily for calculations, OpenBuildings Designer is slow. Users often experience:

• Slow startup times
• Slow rendering
• Slow model navigation
• Slow calculation refreshes
• Frequent crashes with large files
• Long training times for new staff

While OpenBuildings Designer can produce visually rich models, the overhead required to get calculations out the door is considerable and negatively impacts the relative efficiency of using the platform over manual design processes.

h2x

h2x is cloud-native and built for speed, and includes the following features designed to help engineers work faster:

• No installation required to start using the platform
• Instant project loading
• Autosave setting
• Real-time updates
• Real-time, instant calculations
• No workstation performance limitations

Because h2x handles calculations in the cloud, an engineer using a basic laptop gets the same high-speed performance as someone with a high-end workstation.

For firms working on tight deadlines or with large design teams, where even a modest improvement in efficiency can significantly improve outcomes, h2x is the superior choice.

Collaboration and Sharing

Most design engineers do not work in isolation: on major projects, multiple engineers are always involved, and they in turn must interface with an ever-growing group of stakeholders and decision makers.

OpenBuildings Designer

OpenBuildings Designer frequently makes it harder for engineers to collaborate, both within their own teams and with outside stakeholders. The platform’s collaborative drawbacks include:

• Needing to share large, locally saved files
• Having to pay for Bentley ProjectWise
• Manual version control
• Constant risk of file overwrites
• Layers of friction slowing collaboration with external engineers

When teams use OpenBuildings Designer, sharing models with stakeholders often becomes a bottleneck that negatively impacts everyone’s collaborative experience.

h2x

Because h2x is browser based, collaboration is in its DNA. Features supporting successful collaboration include:

• Instant cloud sharing
• Version history
• Real-time co-working
• Secure, link-based access
• Simplified QA/QC
• No IT burden or file conflicts

Stakeholders—including clients, contractors, and junior engineers—can share and review designs in minutes, without needing software installed.

For UK firms working across multiple offices with hybrid or remote engineering teams, these collaborative enhancements are transformative.

Training and Talent Onboarding

When onboarding a new design platform and training new team members, every minute spent is downtime when no revenue is being earned. It’s critical to fully consider the total time cost of adopting a new platform.

OpenBuildings Designer requires extensive training for onboarding any new user. The onboarding has been reported to take weeks or even months. Training materials for OpenBuildings come at a high cost, and require pre-existing, Bentley-specific knowledge and know-how. It’s no surprise that there is often considerable difficulty with hiring engineers already familiar with the platform. Together, these issues slow adoption and training and harm profitability.

h2x features a white-glove onboarding process that makes adoption and training easy. Because it was designed by engineers, its intuitive interface mirrors how engineers actually think. Most new users can become functional on the platform within a day, enabling them to be productive almost instantly. h2x is new, so no pre-existing BIM knowledge is needed to operate it.

For firms scaling rapidly or dealing with ongoing junior designer talent shortages, h2x supports faster, easier onboarding.

Download a h2x vs. Hevacomp comparison infographic.

Customer Support

No matter how well-trained a team is on a platform, questions will arise. When that happens, any response delays put projects on hold and can be costly. The h2x customer support team wants its users to succeed, and to do so quickly. h2x offers an unparalleled level of support from real engineers who are invested in solving issues and helping users gain proficiency. Unlike OpenBuildings Designer, which offers support based on a tiered subscription model, h2x offers every user the same level of hands-on support, including immediate chat access. h2x users will not get stuck trying to solve a problem without adequate customer support, or be asked to pay more to get the right help. 

Why h2x Has Become the Preferred Replacement for Hevacomp

The phasing out of legacy program Hevacomp came at the end of years of growing user frustrations. For many, the only reason they stayed with the platform is that they had already invested in the subscription and the cost of training and adopting the program. This isn’t where teams want to be.

Now, design engineers must choose a new platform that will carry them into the next stage of their business. A platform like OpenBuildings Designer shares many of the same built-in performance issues as Hevacomp, while h2x offers a modern interface designed by engineers who have experienced the same design issues and developed intelligent solutions. 

After comparing the two platforms across every meaningful dimension, including workflow, accuracy, code alignment, speed, training burden, collaboration, and real-world usability, it’s clear why many engineering firms have adopted h2x:

1. Fast, clean calculation workflows: Engineers can run HVAC, plumbing, and building services calculations without building unnecessary BIM geometry.
2. Built for mechanical engineers, not architects: The workflow mirrors exactly how engineers think and work.
3. Lightning-fast performance: Cloud architecture eliminates processing delays.
4. Transparent, auditable calculations: Ideal for regulatory submissions and client reporting.
5. Low training burden: Firms can onboard new staff in hours.
6. Perfect for hybrid and remote teams: Cloud collaboration is seamless.
7. Modern, evolving, and future-proof: Frequent updates keep the tool ahead of industry needs.

Frequently Asked Questions: Hevacomp Replacement

Is Hevacomp still supported?

The answer is no. As of January 1st, 2026, Bentley Systems formally ended all support, updates, and patches for the platform. If you’re still running Hevacomp, there are no more security fixes, bug updates, or compliance adjustments coming your way.

What is the best replacement for Hevacomp?

Most MEP and building services engineers have found that h2x is the most logical successor. While OpenBuildings Designer is an option, it still leans on that same legacy calculation engine that made Hevacomp feel slow. h2x was built from the ground up by engineers who wanted something better: a cloud-based tool with CIBSE-verified accuracy and a workflow that actually makes sense the moment you open it.

What is the difference between h2x and OpenBuildings Designer?

It really comes down to focus. OpenBuildings is a massive, “all-in-one” BIM platform that was originally meant for architects; the mechanical tools feel like an afterthought. h2x is different. It’s cloud-native and was designed specifically for MEP engineers. You aren’t fighting through irrelevant architectural menus to get to your HVAC or plumbing calculations. It’s faster, cleaner, and built for a specific job.

Is h2x CIBSE verified?

It is. We know how critical compliance is for UK and global projects, so h2x uses fully CIBSE-verified calculations. You get total transparency, no “black box” math, and you can export audit-ready reports for your clients or regulatory submissions in just a few clicks.

Does h2x work with Revit?

Absolutely. Think of h2x as a partner to Revit, not a rival. Revit looks great, but it can be a headache for complex engineering math. h2x handles the heavy lifting on the calculations and then exports the data, giving you a seamless BIM workflow without the usual friction.

How long does it take to learn h2x?

You won’t need a week-long training course. Most engineers are up and running (actually producing work) within a day. h2x is intuitive because it mirrors the way engineers actually think about a design. Plus, you don’t need years of BIM experience to get the hang of it, which makes onboarding new staff much easier.

Is h2x suitable for remote or hybrid engineering teams?

It’s actually one of the biggest reasons firms switch. Because h2x is browser-based, there’s no software to install and no massive files to ship back and forth. Your team can co-edit a project in real time from anywhere. Whether you’re in the office or working from home, the performance stays the same.

Isn’t it time to upgrade with a platform specifically designed for how you operate? Watch a demo or book a call with h2x today!