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What is retrofit?

Retrofit is “the upgrading of a building to enable it to respond to the imperative of climate change”. It may involve repair, renovation, refurbishment and/or restoration of the building and can be 'deep' - achieving significant reductions in energy consumption (such as our Harpenden EnerPHit Plus project or Bedfordshire Passivhaus Plus); or 'shallow' - achieving minimal energy use reductions. Retrofit can be good - reducing energy consumption and carbon emissions whilst also improving occupant comfort and health, but it can also be poor - failing to make the energy, carbon and financial savings anticipate, and increasing the risk of other issues such as damp, fire and overheating.


We advocate the best practice approach of a holistic whole building intervention where the consequence of each measure taken is fully understood and the the building is considered as a whole, rather than piecemeal parts. We take the fabric first approach, using natural materials as far as possible to improve fabric energy efficiency before implementing low carbon technologies such as solar pv and heat pumps. 

What standards can be achieved?

The Passivhaus Institute have an EnerPHit standard for retrofitting existing buildings up to Passivhaus standard where the criteria are slightly more relaxed the the new-build Passivhaus ones, to take into account existing building conditions and restrictions. If EnerPHit is not feasible, the AECB have also introduced their own Retrofit Standard which is slightly more relaxed than EnerPHit but still approached and calculated in the same way using PHPP software.  



LETI write: 'There is currently a climate emergency caused by greenhouse gases being released into the atmosphere and we emit huge amounts of carbon dioxide by heating and using hot water in our homes. What may not be as obvious is that our existing homes are by far the worst polluters in the housing sector. Of all the operational emissions that come from buildings in the UK, 69% come from energy use in the domestic stock which alone is responsible for 18% of our annual national emissions.'

But it is important to realise that retrofitting isn't just about reducing the carbon emissions of our homes; it also reduces fuel bills, improves health and well-being and generally makes home that much nicer to be in, all the more important now that many of us are working from there too and people who live in warm, comfortable homes are happier, healthier and more productive at work.

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