Is my home too draughty for MVHR?

Airtightness pressure test kit installed in retrofit home achieving 1 score

As much as 25% of the heat loss of a building is via air leakages in the building fabric (ie, draughts). The airtightness of the building fabric is therefore an important metric to measure and improve as much as possible… Continue reading

Cotswold new build is 55x more airtight than Building Regs and 3x more airtight than Passivhaus

It is subtle and understated in its impact on UK housing, but this new build bungalow home is one of the most energy efficient buildings in the world – and represents the future of housebuilding in the UK and Europe.… Continue reading

What’s the difference between an MVHR Heat Exchanger and an Enthalpy that recovers moisture?

Internal mechanism of an MVHR unit

If you’re researching installing a Mechanical Ventilation with Heat Recovery (MVHR) system for your project, you may have heard of an Enthalpy heat exchanger or ERV (Energy Recovery Ventilation). But what is an “Enthalpy” heat exchanger? How does it change… Continue reading

How the price of an MVHR relates to quality and performance

Crushed and bent flexi-duct will increase noise in an MVHR

I’ve written before about the average price of a high quality Mechanical Ventilation Heat Recovery (MVHR) installation, which includes an itemised price for each detailed ductwork layout, materials supply, installation and commissioning (airflow balancing and client handover). Today I’m going… Continue reading

How much duct space do you need around the house for an MVHR system?

MVHR with ComfoCool installed in a residential home showing spacing requirements

The most common question I’m asked by people interested in mechanical ventilation with heat recovery (MVHR), low energy building design or Passivhaus is: How much space do we need for the ducts in an MVHR ventilation system? Variations to the… Continue reading

How airtightness testing differs between Building Regs and Passive House – and why it matters so much

Using a smoke pen to detect leaks during airtightness testing

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… Continue reading