MVHR and building physics knowledge for healthy, comfortable and energy efficient homes
Heat, Space and Light Ltd has completed the design, supply and commissioning of a Passivhaus-specification MVHR ventilation system for a luxury new build in the northwest of England. The home was also tested by our building airtightness team and achieved an incredibly airtight result of 0.76 m3hr/m2 @50Pa. It’s only slightly shy of a fully-certified … Read more
Heat, Space and Light Ltd has completed the design, supply and commissioning of an MVHR system in a four-storey London terraced home. The property has undergone a deep retrofit to EnerPHit criteria, which is the retrofit standard for Passivhaus. Passivhaus building standards are a stringent methodology using high levels of insulation, airtightness and ventilation with … Read more
Forensic Airtightness Testing and Strategy by Heat, Space and Light Ltd has helped a new build home in Dorset achieve a drop in its final airtightness rate that will result in £100s of heating savings every year, turning it from a leaky home to an airtight home. Forensic air testing improves Air Permeability from 6.4 … Read more
Building Regulations Part F wants to know how much air (in m3hr) passes through each metre square area of the fabric (m2). This is the Air Permeability (AP or m3.hr/m2) figure of the building. To get the AP figure, one calculates the volume of air in the property. Then one calculates the total external envelope … Read more
Why aren’t passive houses (AKA Passivhaus) mainstream? Why isn’t every new home built in the UK produced to the design specifications of passive houses? Here I’ll go through what’s bad about passive houses, whether it’s true, and what might be done to fix the problems. 1) Passive Houses are boxy and ugly Passive houses are … Read more
The Passive House Form Factor quantifies the relationship between the living area of the building and the total amount of surface area that heat can escape from. The calculation is simple: Total heat loss area ÷ floor area = Form Factor The Form Factor of a building is key in low energy design because it … Read more
Are eco-friendly passive houses for rich people? Eco warriors? Self-builders? Housing associations? Or are they only the preserve of our more logical, engineering-minded continental cousins in Germany? Passive Houses are for everyone. To build a Passive House, ie, one that runs at ten per cent of normal household bills, doesn’t need any extra technology like air-source heat … Read more
One of my friends remarked today that their colleague was asking about that “German eco home, the one where you can’t open the windows…” The idea that you can’t open the windows in a Passive House comes from a misconception regarding the clever way that Passive Houses regulate the heating and cooling of a home. … Read more
The number assigned to a building fabric element (eg, a window) that represents its thermal resistance is called its U-value. A U-value tells us how quickly or slowly it takes for heat to pass through it. Fabrics with lower U-values are better insulators than those with higher U-values. Part L of the UK Building Regulations … Read more
Not many UK builders have embraced PassivHaus principles yet. Below are a few ways that builders in the UK can ruin low energy homes, either by ignoring or failing to understand the new wave of low energy design and build techniques that help create modern, ultra-comfortable, money-saving eco homes. 1) Ignoring the airtightness membrane UK Building … Read more