Mark Tiramani, the self-builder behind the UK's first certified Passivhaus, shares his experience of building Y Foel and how this got him interested in the Passive House Planning Package (PHPP). He explains what PHPP is and why it's a valuable tool.
Interview with Mark Tiramani
Mark and his wife Shirley first came up with the idea of building their own house when they were working in New York, USA. While backpacking in Upstate New York at the weekends, they met somebody who really impressed upon them the idea of treading lightly on the planet.
Initially they dreamed of a straw bale build but on returning to the UK they came across the concept of Passivhaus.
The plot had an abandoned cottage on it
Their Designer/Builder Introduced Them to the Concept of Passivhaus
John Williamson from JPW Construction mentioned Passivhaus to Mark and Shirley.
Mark, who had spent 13 years living in Germany, immediately warmed to the idea: “I thought, it's actually a way of working out how much energy you would require to heat a house and run it. That got me interested.”
The plot was cleared and new foundations were laid
PHPP is a Sophisticated Set of Integrated Spreadsheets
PHPP is an Excel workbook, and accompanying user guide, for optimising the thermal performance of a building.
Mark did the PHPP calculations for his windows
Using PHPP Helped Dispel the Myths and Mystery!
As this was very early days for Passivhaus in the UK when the project started (at the end of 2002), a lack of resources and expertise meant that Mark decided to do some of the PHPP work himself.
However, having taken this step, it helped him reach a much deeper understanding of what was going on.
PHPP is simply a tool to work out what a building is going to do thermodynamically. Using building physics it joins up all the dots.
You Need the Specifications of the Products You're Using
In order for PHPP to produce meaningful results it needs reliable data going in.
Mark gives an example of how he added in the required specifications of a window by doing finite element analysis (with software called Therm).
The window has to be broken down into all its elements, such as the glazing, the coating, the spacer and the actual frame, etc. Precise measurements are required at every stage of the process or accuracy will decrease. The numbers that come out of this step go into PHPP.
*This stage was only necessary because the windows Mark talks about were not certified.
PHPP Has a Database of Certified Products
PHPP has a database of products that have been tried and tested. So if you are using one of these products you are already a step ahead because the specification data will be on a drop down list and just needs to be selected.
PHPP Also Takes into Account Factors Including Climate and Shading
The PHPP calculations go beyond just using product data. It needs specific information on the climate, shading, properties of the ground, thermal bridges and so on.
Mark says: “It's calculating a whole bunch of things. The things that people know about are the specific space-heating requirement. That's the famous 15kWh per m2 per year. You can pass on that alone plus overheating plus total primary energy consumption. So there's basically those three things but you can also pass on the heat load or heating load. That's calculated based on climate data.”
The PHPP climate data for Mark's house
Recently Mark Has Redone All PHPP Calculations for his House
Although Mark did the PHPP calculations for his windows in 2009, recently he decided to start from scratch and do the whole house!
Now that he's much more familiar with PHPP the process was a lot easier and he is confident that the figures are extremely accurate now.
There are some elements that can never be 100% accurate though. Mark says: “A couple of things are very difficult to do in PHPP, really. Shading is one. It's a bit down to guesswork, so it's that artistic licence.”
Every Iteration of PHPP Potentially Reduces Errors
Mark knows that he made some minor mistakes when he did the PHPP calculations in 2009 but as it goes into so much detail and in so many areas, small errors or incorrect assumptions may not skew the overall calculations too much.
PHPP is also getting better at spotting user errors. For example, if you accidentally misplaced a decimal point it might realise and flag up that this is an unrealistic figure.
Find Out More
What's it Like to Live in a Passivhaus?
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