BUILD COST CLINIC
A key component of Passivhaus buildings, MVHR can help to enhance air quality, improve a home’s energy efficiency and reduce energy bills, as Tim Phillips explains
TIM PHILLIPS
Is a quantity surveyor and runs Quantiv.uk, with almost 30 years of experience across the commercial and residential sector. @timphillips71
Mechanical Ventilation with Heat Recover y (MVHR) is a ventilation system that is now widely used in well-insulated and energy-efficient homes, and is a mandator y constituent in ‘Passivhaus’ buildings. MVHR systems are critical to meeting Building Regulations for energy conservation and indoor air quality.
Having a good understanding of these systems is essential for architects, tradespeople, homeowners and builders, since they are key to the creation of energy-efficient environments that are a pleasure to live in.
MVHR systems are designed to run all year, controlling ventilation by removing stale air in the home from multiple rooms and providing fresh outdoor air. They are not to be confused with MEV (Mechanical Extract Ventilation) systems, which are shown to waste around nine times more energy than its MVHR equivalent.
The ability to recover heat is what distinguishes MVHR from other ventilation systems as it effectively transfers heat from the extracted stale air to the incoming fresh air. This heat exchange mechanism, which is passive in nature, keeps the inside temperature comfortable while minimising heat loss. MVHR systems can also help to enhance air quality for people with respirator y illnesses and allergies, as well as minimise common problems that affect many homes, like mould and moisture build-up, as they passively dehumidify the air.
With the UK facing everincreasing energy bills, MVHR systems play a crucial role in achieving household energy efficiency and heating cost reduction. Below we’ll look at the key costs involved in buying and installing a MVHR system and how savings can be made as a result.
COST INCREASES
Unfortunately, MVHR systems are not an exception to the general price increases seen across the construction industry. Both ducting components and units consist of price-affected materials commonly used across the construction sector. But the good news is they are more affordable than they have been in perhaps the last decade, as the drive to achieve more sustainable homes has accelerated the technology behind the systems. Ultimately, they have the ability (when correctly designed and installed), to pay for themselves in terms of future savings, which we’ll explore below.
SYSTEM COSTS
When considering system costs, it is important to distinguish between standard economy UK MVHR systems and those achieving best practice standards, which are often with Passivhaus accreditation (see table opposite
