Plans showing proposed building in Chester

EnerPHit Retrofit 4: the Passivhaus Planning Package File

Posted on 12/10/22

In this article I’ll touch lightly on the Passivhaus Planning Package (PHPP). This is a very complex Excel sheet that automatically computes vast amounts of data to determine the performance of a proposed building. The PHPP is the basis of every Passivhaus project and will be referred to throughout the process. It contains everything necessary for effectively designing a properly functioning Passivhaus.

Calculating Energy Demand

The PHPP prepares an energy balance and calculates the annual Energy Demand of the building based on the user input relating to the building’s characteristics. Amongst other things, the package calculates:

  • The annual heating demand [kWh/(m²a)] and maximum heating load [W/m²]

  • Summer thermal comfort

  • Annual primary energy demand for the whole building [kWh/(m²a)].

It does this by dealing with the following aspects: 

  • Dimensioning of individual components (building component assemblies including U-value calculation, quality of windows, shading, ventilation etc.) and their influence on the energy balance of the building in winter as well as in summer

  • Dimensioning of the heating load and cooling load

  • Calculating domestic hot water (DHW) demand and design of DHW systems.

  • Dimensioning of the mechanical systems for the entire building: heating, cooling, hot water provision

  • Verification of the energy efficiency of the building concept in its entirety

What criteria am I going to be working to?

The PHPP forms the basis for quality assurance and certification of a building as a Passivhaus or an EnerPHit retrofit. The PHPP can be used across the world’s climates and is available in a number of languages.

The results can confirm if performance achieves Passivhaus Classic, Plus or Premium status as well as EnerPHit (Classic, Plus or Premium) along with Passivhaus Institute Low Energy Home Standard. As our project entails the retrofit and refurbishment of an existing dwelling, I’ll be working to the EnerPHit criteria (the same principles but slightly less onerous than Passivhaus).

Generating energy from renewable sources

As well as wanting to reduce my Yearly Energy Demand, I also want to do what I can to generate as much as I sensibly can from renewable sources, rather than being reliant on the grid and what are, currently, high and volatile prices. I am therefore aiming to achieve the EnerPHit Plus standard.
The Plus standard requires a reduction in the Primary Energy Demand of the Building of 25% from the EnerPHit base line, as well as a significant increase in the amount of energy used being generated from renewable sources.

Achieving EnerPHit Plus status

To achieve EnerPHit Plus status, I’ll need to generate in the region of 60 kWh/(m²a) – depending on whether I work to the standard criteria or the alternative criteria, which is calculated within the PHPP for each particular project. To put that in perspective, we inherited a 17 panel, 3kW PV system already installed at the property; the PHPP estimates that this will generate 1685kWh/a. To achieve the 60 kWh/(m²a) I’ll need to generate another 5,800kWh per annum means installing in the region of 16 additional PV panels on the roof, each of which will generate in the region of 400W, as opposed to the 175W that the existing ones manage to.

The Step by Step EnerPHit Retrofit Plan

So, I have established that I am aiming to achieve EnerPHit Plus standard but I also want to do it over a series of phases to spread costs and the disruption to the family as we will be living in the property throughout the works.
Helpfully, the Passivhaus Institut has created a version of the PHPP that allows the Certified Designer to sequence work into different phases. This helps to achieve an efficient building as a final project, with all the different elements working harmoniously, but allows the project team to separate the works. Using this approach allows the designer to confirm the end-performance of the building and acquire a “pre-certification” from the Institut. This then provides the client with reassurance.

The EnerPHit Retrofit Plan

Once the PHPP package has been completed, another Excel file, the EnerPHit Retrofit Plan, is opened and linked to the PHPP file. This imports the key data and provides a more reader-friendly collection of data that clearly sets out the different phases and scopes of work and the impact each will have on the performance of the building. I have been working on the PHPP file for a while now and have been tweaking elements to strike the best balance between performance and cost. In the next article I’ll go a bit deeper into the process and provide draft results of the PHPP to demonstrate what can be achieved.
To find out more about EnerPHit and Passivhaus design, contact our team.
Illustration shows: Table of required criteria – Traynor, James. 2019. EnerPHit. A step by step guide to low energy retrofit. RIBA Publishing.

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