The numbers are in (1)
Part 1 of a 5-part series in which we quantify the value the Flexi House system can provide Kiwis looking to build. This blog explores thermal performance in relation to the new H1 Building Code updates.
At Flexi House, we’re committed to helping Kiwis build better than the bare minimum building code requirements.
How much better? 46% better to be exact.
We had thermal modelling completed by our friends at Via Architecture (Passive House experts) that demonstrates the Flexi House Show Home in Cromwell is 46% more thermally efficient than the same building built to the new H1 standards of the New Zealand Building Code.
Hang on a minute, what’s thermal modelling?
Thermal modelling involves the analysis and simulation of the thermal performance and energy efficiency of a building. Software is used to create a virtual model of a building and predict its thermal performance under various environmental conditions.
Thermal modelling looks at factors such as a building's orientation, insulation, window properties, shading, mechanical ventilation, heating and air-conditioning systems. These elements are simulated to forecast how much energy the building will consume and its indoor thermal comfort.
Via Architecture modelled our Show Home in the Passive House Planning Package software (PHPP), which is used worldwide by architects and planners seeking reliable data about the performance of their buildings.
The Flexi House was compared to a building of the same size but with an envelope built to New Zealand's Building Code minimum requirements. It was also compared to a building built to the Passive House standard for a Low Energy Building to show how much improvement is needed to get to the next step.
The results speak for themselves. The annual heating demand was determined to be 4.3MWh/year for the Flexi House, compared to 7.9MWh/year for the minimum code building.
As heating and cooling make up approximately 50% of household power consumption, a family living in a Flexi House could pay $541 less per year on average for their power than a family living in a home built to the newly updated H1 requirements.
And this is just the beginning.
While we’re stoked about the energy efficiency of our design, we’re always looking for ways to improve. The report shows higher performing buildings like a Passive House Low Energy building and the Flexi House design have a higher frequency of overheating if shading and window treatments are not considered.
Overheating is the result of excessive solar heat gain combined with higher levels of insulation and airtightness, leading to more heat retention. We already use low-e glazing which helps to mitigate some of the solar heat gain, and we could reduce the overheating frequency further by adding solar shading like eyebrows above the windows. This would mitigate solar heat gain during summer when the sun is higher in the sky.
Overheating can also be attributed to the location of the Flexi House. Cromwell, and Central Otago in general, is notoriously hot in summer! Part of the reason we were so keen to build here in the first place was to test the limits of the Flexi system in one of the harshest climates in the country.
You can check out the report here.
Now thermal modelling is one thing, but we've also heard from the orchard workers themselves how much they love how warm and cosy their Flexi House is.
Back in March when much of the South Island was experiencing a cold snap and there was fresh snow on the Pisa Range, we received a message from Euan, the orchard manager. He’d got out the thermometer to check the temperature inside the Flexi House.
The internal temperature of the Flexi House was 20.8 degrees without any heating, while it was still only 10 degrees outside!
The Flexi House had retained the heat passively generated during the previous day from cooking and cleaning, using mechanical ventilation to maintain the indoor temperature whilst keeping the air fresh.
We reckon it must be the best workers’ accommodation in the country!
Imagine how much easier it would be to get out of bed on those winter mornings if your home was a constant 20 degrees without heating. Add to that a 46% reduction in your heating bill compared to a home built to minimum code, reducing the cost to you AND the planet, and you can see how the benefits start to stack up.
But don't just take our word for it - you can feel the Flexi difference for yourself. If you're in the area and want to visit the Show Home, get in touch and we'll arrange a time for a tour! As the Flexi House Show Home is located on an operational orchard, viewings are by appointment only.
Flexi House is currently offering a free Kickoff Design Package that is designed to get you a floor plan and a price so you can start making decisions about whether a Flexi House is right for you. If you haven’t already, simply fill out our quick Kickoff form and book a time to jump on a call with us. We look forward to hearing about what you want to build and how we can help you into a warm, healthy, energy-efficient home.
