We work as energy consultants on a huge range of Passivhaus and low energy developments both large and small scale; our collective experience is unrivalled in the UK.

Passivhaus & low energy

We are working as energy consultants on a huge range of Passivhaus and low energy developments from large scale commercial to self-build; our collective experience is unrivalled in the UK.

Passivhaus is still new to the UK building industry; use our knowledge to ensure you achieve the right quality with the least risk, stress and cost.

Because our understanding is based on first principles we can apply our knowledge to a wide range of problems; we enjoy the challenge of non-domestic and unusual projects.

We work best when we can get involved at an early stage. Optimised form and glazing is the most effective way of driving out complexity, keeping down cost and reducing design and construction time.

The services we offer will be dictated by your need; from full support to the occasional phone call we will tailor to your needs. The first project always needs more involvement, but as you learn you’ll need us less and less.

Typically our role may involve:

  • PHPP (Passivhaus modelling software) to give sensitivity analysis and optimisation
  • Building design advice; shape, glazing, orientation etc.
  • Construction advice with regard choice of materials, airtightness & minimising thermal bridging
  • Product selection, feedback and analysis
  • Review of building services – we can also design them for you
  • Additional modelling such as thermal bridge & daylight calculations
  • Planning documents relating to energy
  • Design team support; workshops, training & more
  • Critical on-site training, support & troubleshooting
  • Aftercare

An important aspect of our work is how the building works in practice. We will stick around to find out what works best, and to help with any issues you have.

Building Services

Services to match a low energy building shell. We design building services that are simple, easy to understand and reflect the fabric-first approach. Understanding both the fabric and the services means a building that dove-tails beautifully.

Thermal Bridging

We are very experienced at thermal bridge calculations and provide a rounded service – not just undertaking the calculations but helping to identify what needs modelling, ensure they are incorporated in SAP or PHPP correctly and most importantly providing practical advice on how the design can be changed to improve the performance.

Call or email us to discuss your thermal bridging needs

WARM can advise on thermal bridging for PHPP and SAP assessment, and complete calculations. Our extensive experience means that we can often minimise the number of calculations (and expense) required to achieve the best overall result.

If you wish to understand thermal bridging more yourself, or even wish to do the calculations, CarbonLite offers online and classroom-based courses.


The analysis and avoidance of Thermal Bridging is essential in Passivhaus assessments, although calculations can usually be avoided by inspection of junctions and using a rule of thumb.

SAP and Part L

To reduce the thermal bridging impact in SAP assessments either accredited details must be used or calculations performed. The improvement in the SAP result for good designs can be substantial, saving in fabric specification and renewables elsewhere.

WARM can complete a Thermal Bridging review to identify whether it is worth completing calculations, and which calculations will yield the best results.