Is Passivhaus retrofit right for you?

The challenge of retrofitting the existing housing stock is key to achieving net-zero. The Passivhaus retrofit standard, EnerPHit, can provide a robust methodology but may not always be feasible or appropriate. On retrofit the Trust advises the following:

		1 - INVESTIGATE EXISTING  Assess & evaluate the existing condition of the building fabric. This may involve calculating u-values or even measuring the performance of the current building envelope. Initial surveys and air-tests to determine the building’s airtightness may be useful.
		2 - CREATE A WHOLE HOUSE PLAN This will set out all feasible upgrade measures for your building, and most importantly, in what order they will need to be completed. Setting out the big picture from the start helps prevent ‘carbon lock-in’ and avoids choosing energy-saving measures that may prohibit other improvements later.  We would always advise creating a Passivhaus Planning Package (PHPP) model to understand where you are starting from and what each measure will achieve in terms of energy and comfort improvements.
		3 - CONSIDER A PHASED APPROACH  The whole house plan may seem expensive and overwhelming, but everything does not need to be done at once. Consider a step-by-step approach with a plan that spreads both the costs and potential disruption. Sequencing is key!
		4 - AIM FOR ENERPHIT (IF FEASIBLE)  The depth and extent of measures that you will need to take to reach the exacting Passivhaus EnerPHit standard will, in some part, depend on factors beyond your control such as the shape, orientation and glazing proportion in your building.  Everybody will also have budget limitations as well as other practicalities such as the level of disruption that is considered acceptable.  So, EnerPHit will not be feasible in all cases.  However, if your budget and building allows, then go for it and reap the rewards in terms of both energy and comfort.
		5 - ADOPT AN ELEMENTAL APPROACH  If you aren’t able to model in full, or are advised achieving EnerPHit is not feasible in your case, you can still adopt the recommended EnerPHit component values (or better), which will see you achieve a very efficient and comfortable building.

 

 

Further Information

Passivhaus retrofit

10th September 2020

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