EuroPHit – Passivhaus Retrofit Projects:
step by step
Once you start to look at retrofitting your house and making it cosy and warm, with reduced fuel bills and harm to the environment, you realise that it is not a cheap option. Many people including myself cannot afford to retrofit our house to the full Passivhaus retrofit standard of EnerPHit, but would love to. On a tight budget we have two options, option 1 downgrade the specification, use thinner insulation, not addressing the difficult bits such as the foundation thermal bridge, etc. Option 2 is to do the retrofit in stages, ensuring each stage is done to a good standard as part of an overall plan to eventually get to the Passivhaus retrofit standard of EnerPHit. This may take 10 years to complete or even 50 years, with new owners of the house taking on the plan and finishing it off.
This approach is an approach the Passivhaus institute in Germany have developed called the EuroPHit standard. It is a planned retrofit over a number of stages – you decide how many. At each stage you get a certificate, to show your achievement and to give to future owners if you move, showing you have done it properly. I now EuroPHit sounds like a doggy keep fit place, but it makes a lot of sense, see the graph below showing how if you opt for option 1 a shallow retrofit you may be locked into a much lower performing house in the long run or have to re do what you have done, which will cost more in the end.
Any retrofit project is not risks free, there are many things that need to be considered, interstitial condensation and ventilation to name but two. Any step by step retrofit needs to be planned well so that each step can stand alone. You need to prevent rain getting in that could damage materials, steer clear of introducing new thermal bridges that could cause mould or discomfort and avoid excessive re-working. If intermediate stages will be lengthy you will want to avoid an unfinished or ugly look.
Deciding on phasing can be complicated. Take windows for example, you don’t want trickle vents as you won’t need them later, but you need adequate ventilation now, so you may wish to install the MVHR at the same stage as the windows. But where do you position your new windows? If you’re planning external wall insulation and render the windows should, ideally be position out in the insulation layer. We often position the windows within a plywood box to ensure the optimum location. However, if you are not installing the external wall at this stage then the external appearance of your house with the windows projected will not look good, and you will probably suffer from condensation and mould around the inside of the window due to cold bridges. The European solution to this is to install your windows flush with the outside then the new insulation can cover part of the frame, when you’re ready for this stage and all is good. Unfortunately, this works best with internally opening windows where the frame can be insulated on the outside without hindering the opening. If you want outward opening windows which is the norm in the UK this is more difficult, and you will probably want to install the windows temporarily and then move them out at a later stage with associated costs. Of the insulation could be completed in a stage prior to the windows.
We can help you plan your retrofit, work with you to agree the final specification whether that’s EnerPHit or another more suitable target for your home. Then split this down into elements, that can be priced and grouped into workable stages. These stages can also consider the maintenance requirements of your home, for example if your roof is likely to require repairing within 5-years, this should then be included in the first or second stage.
Our EuroPHit Journey
On a personal note as a family we are planning a EuroPHit renovation on our home. A previously unloved 1970’s build the windows and cladding needs replacing, so we are developing our retrofit plan and putting in for planning permission.
If you are interested in hearing more about how a step by step process can work for you contact us.