PSI Value Calculator
We understand there are many considerations when you are designing your building to meet the requirement for Building Regulations.
Traditional thermal modelling software can be complex, time-consuming and expensive; while the defaults allowable can often have a detrimental effect on the overall cost of construction required to meet regulations.
This is often a challenge for technical teams, housebuilders, architects and SAP assessors. But with AutoPSI as your dedicated PSI value software, you can do PSI value calculations with speed and pass each regulatory assessment with ease.
What makes AutoPSI so powerful?
| Feature | What it means for you |
|---|---|
| Unrivalled Speed | Calculate PSI values in minutesOur efficient PSI value calculator software can determine PSI values quickly, without compromising on results. |
| Intuitive Interface | Drag and drop bridges and layers |
| Fully Customisable | Custom junction builds |
| Accuracy | Meets self-accreditation in BR497 for 2D calculations |
| Online | Accessible anywhere, anytime |
| Collaborative | Share designs with your team and clients |
Why is PSI Value Calculation Necessary for Construction Design?
A PSI value calculation is important because it tracks heat loss in construction junctions, and our PSI value calculator makes this easier with templates and a user-friendly interface. But what makes building thermal modelling software such a significant tool within the construction design industry?
PSI values are required by SAP/EPC building regulations to ensure that you comply with energy performance standards. They require a thermal bridging component, whether you include a separate PSI value or not. When using an assumed PSI value, you’re likely not going to pass.
A reliable PSI value calculation has many benefits:
- Stronger thermal bridging component: A PSI value (linear thermal transmittance), allows you to redesign the two thermal elements of a thermal bridge or junction to avoid greater heat loss.
- Sustainability: With accurate PSI values, you can design energy-saving spaces and remove unnecessary parts of a new build design, which can also save money further down the line.
- Reduce condensation and mould risks: A thermal bridge can cause harmful condensation and mould to spread. PSI value calculations will inform you of risks in advance when doing renovations.
[Try AutoPSI today](https://app.autopsi.co.uk/register) with a free 14-day trial and start streamlining your PSI value calculations.
How it Works
From U-values to non-repeating thermal bridges, PSI values play a big role in building design. With AutoPSI, you don’t need to worry about how to calculate a PSI value, because the values you need are just a few clicks away.
- Choose your junctions: Start by selecting from a set of SAP required junctions (windows, doors, gables, etc.), including options for timber, masonry and steel frames.
- Amend your values: Amend the K-values, thickness and other dimensions of your bridges and layers.
- Control your junctions: At this point in the calculation, you can delete, move and amend any thermal bridge or layer you need to, as per your own unique requirements.
- Change materials or add more layers: Utilise the user-friendly drop-down menu to change your materials or add more layers before initiating the PSI calculations.
- Calculate your PSI value at the click of a button: Within minutes, you’ll have your unbridged U-values, Q, F-values, and PSI values from our efficient PSI calculator, all available in a downloadable PDF report.
Let AutoPSI uncomplicate the PSI formula for you. [Try AutoPSI free](https://app.autopsi.co.uk/register) to start using our innovative PSI value calculator today.
AutoPSI: Innovative & Fast PSI Value Calculation Software
The AutoPSI thermal modelling tool was developed for the construction design industry.
The AutoPSI thermal modelling tool was developed for the construction design industry.
Our technical services team has worked on many projects and designed linear thermal transmittance calculation tools and other bespoke software based on in-depth experience. With an affordable monthly or annual licence available in various packages, you can also take advantage of our easy-to-use and time-saving PSI value calculator and simplify your processes.
Streamline your SAP calculations to ensure your property will be meeting compliance standards. [Try AutoPSI for free today](https://app.autopsi.co.uk/register).
When targeting compliance with Part L of the Building Regulations,
Our technical support team can review and support you across your projects to ensure junctions are accurately modeled.
Achieving compliance with increasingly stringent energy efficiency requirements necessitates a thorough understanding and accurate assessment of thermal bridges. What was once a secondary consideration is now a crucial requirement for meeting building regulations and minimizing the performance gap between design and actual energy use.
How to calculate a PSI value
Five steps from an empty canvas to a calculated Ψ-value and fRSI you can put in a submission.
Start from a template, or draw it
Pick the closest junction from the template library, or build it from scratch in Free Draw when the detail is non-standard.
Set the layers and materials
Drag and drop the build-up, then assign materials from the library or create bespoke ones with your own conductivity values.
Add bridges and boundaries
Place wall ties, lintels and other bridging elements, and set the internal and external boundary conditions.
Add the U-values
Set the U-value arrows for each flanking element. These define the one-dimensional heat loss the Ψ-value is measured against.
Calculate and export
Run the calculation to get the Ψ-value and fRSI, then export a report you can attach to a SAP submission or project record.
Common questions
How do you calculate a PSI value?
A Ψ-value is the difference between the total heat loss through a modelled junction and the one-dimensional heat loss through the flanking elements either side of it. The modelling is what produces the first figure: a 2D thermal model of the junction, solved for the temperature distribution through it. AutoPSI does that calculation and returns the Ψ-value directly, so you are not deriving it by hand. What PSI values are covers the underlying principle.
Is there a free PSI value calculator?
You can model junctions and get real results during a 14-day free trial, which needs a card to start. After that it is £749 a year or £69 a month for a single licence. See pricing.
Is this a thermal bridging calculator as well?
It is the same thing. A thermal bridge is the junction; the Ψ-value is the measure of heat loss through it. AutoPSI also returns fRSI, the surface temperature factor used to assess condensation and mould risk, which matters most on retrofit.
Can I use the results in a SAP submission?
Yes. Calculations meet BR497 and BS EN ISO 10211:2017 Annex C, and are acceptable for direct use in formal SAP submissions. See new build for why bespoke values usually beat the SAP Table K1 defaults.
Does it do 3D calculations?
Not at present. AutoPSI covers 2D calculations, with self-accreditation in BR497 for 2D work, which is what the large majority of junction assessments require.