Forensic airtightness test gives 30% lifetime heating bill savings

Airtightness Test Kit mounted in hallway of London retrofit 2021

Heat, Space and Light Ltd technicians have conducted forensic airtightness testing on a renovated London Victorian end-of-terrace. The results of the four-hour visit will have improved its comfort, energy efficiency and acoustics by up to 30 per cent, and lowered the home’s heating bills for life. The forensic airtightness pressure test was conducted over four … Read more

Hygiene Ventilation and why it should be designed into homes and offices

Filters for a Zehnder ComfoAir MVHR unit

When we consider examples of good hygiene in our home, we may think of easy-to-clean materials, strong disinfectants and mops and buckets. But as Covid-19 is proving, hygiene in the home also relates significantly to the air we breathe indoors, and the bacterial and viral particles suspended within the air around us. There are many … Read more

So who are Passive Houses for?

Airtightness Test Kit mounted in hallway of London retrofit 2021

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

Can you open the windows in a PassivHaus?

Zehnder Comfoair MVHR installed in utility room

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

How to calculate how much energy your windows will save from its U-value

Old cottage made airtight and insulated with woodfibre insulation

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

Five most common problems with Mechanical Heat Recovery (MVHR) Units

MVHR Schematic showing how warm ambient air can affect the accuracy of the Heat Exchanger Efficiency

Modern homes are shifting towards increasing levels of airtightness in order to secure heat-saving benefits. With increasing levels of airtightness comes a need for a ventilation strategy. For Passivhaus, this means an MVHR system. Heat from the home is lost in two ways: through the fabric elements as it passes through our walls, windows, doors, … Read more

How poor ventilation in your office is making you tired and ill

Mould in a classroom of a school near the window frame

We spend a huge part of our lives indoors – I’ve spent 96 per cent of my last 24 hours indoors, and it’s not an unusual day for me in winter. Consider your day. How long were you actually outside in the sunshine (or rain) altogether today? During mid-winter in England here was my typical day: … Read more