Knowing that the construction industry has patchy knowledge and skills in Domestic Ventilation, we are offering a bespoke service for our customers in terms of MVHR specification, design and project support.
We put ourselves in the shoes of our customers, as we don’t like the usual sell-and-run approach.
We design and specify to, what we deem true best practice standards, derived from the Passive House methodology:
The quiet operation of a system, optimised indoor air quality, minimal heat losses and no-compormise ducting are properties that are applicable to all types of buildings, not just Passive House.
Almost all companies in the UK specify domestic ventilation rates to comply with Building Regulations, without considering what the outcome is and how it could be optimised.
For the end-user it is the outcome that counts, not just the tick in the box?
When it comes to lacking extract air flow rates, the results are often obvious, as probably condensation and mould can occur. When it comes to lacking air supply rates, it is less obvious, as occupants get used to poor indoor air quality. But there is a risk associated to the long-term exposure to poor indoor air.
The English, Welsh and Scottish metodology for determining the minimum overall ventilation rates for MVHR systems is based on the floor area and the number of bedrooms (England) or habitable rooms (in Scotland). Then for the indivual rooms the overall rate is split according to the volume of the room. There is no consideration to the use and occupancy of the habitable rooms.
This means that bedrooms and studies end up typically with ventilation rates of 3-8 l/s. In reality this will translate into IAQ levels of 1,250 to 1,600 ppm of CO2, which is a high level of air pollution, according to BS 40102.
1000ppm of CO2 is a long-established benchmark between poor and acceptable IAQ, stemming back to the mid 19th century, by scientist Max von Pettenkofer.
A Scottish study, investigating the indoor air quality of modern homes found that the CO2 levels averaged at 1,834 ppm. It concluded:
“Reducing ventilation rates … without providing a planned and effective ventilation strategy is likely to result in a more toxic and hazardous indoor
environment, with concurrent and significant negative long-term and insidious impacts on public health.”
It is not so much the short time exposure, but the risk of long-term effect on the health and wellbeing of occupants, that is the problem with mediocre ventilation rates.
We therefore are not just looking at the regulatory minimum values, but over and above this, we apply a number of best practice considerations, to make sure that the IAQ in critical habitable rooms is good (up to 1000ppm typically).
We consider the use and occupancy of each room, the usage frequency and length, as all of these are important factors for the health and wellbeing of the occupants.
Sadly hardly any other company takes this into consideration.
Noise is the biggest obstable in user-aceptance of domestic ventilation systems. You might think that the industry pays particular attention to noise levels, but unfortunately this is not the case.
A European study concluded: “Many people complain about the noise, and some people change the operation of the MVHR system or even destroy the system.” https://dael.euracoustics.org/confs/fa2023/data/articles/000644.pdf
We have come across MVHR systems that the users switched off at night, because of noise. The picture shows the results of such intermittant operation of an MVHR that was meant to operate continually.
We specify MVHR systems with the best noise attenuators the industry offers, to make your system almost inaudible.
We charge for our MVHR designs, as we believe that a great service can only be delivered, when we take time to get it right. We listen to your individual requirements and carefully consider your house design, including section drawings and joist layout.
After the draft layout is finished, we will consult with the customer, architect or builder, to make sure the customer gets what he wants and that the system can be installed as such. We are happy to revise the drawing slightly to make it perfect. Up to 5 iterations are included in the design fee.
Our 3d designs are showing the duct runs, duct sizes, components, terminals, insulation, controllers, air flow rates and the MVHR system. We show the plant space in great detail from various angles, as this is the most complex part of the system.
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Scottish Homebuilding & Renovating Show Glasgow PAUL Heat Recovery is exhibiting at the SEC in Glasgow on the 9th and 10th May 2026. Please visit…
Big Magic Installer Training May 2026 PAUL Heat Recovery hosts a product training event for the Big Magic MVHR system on Thursday 7th May 2026…
Launch of the UK Zehnder Academy As Approved Zehnder Partner we were invited for the official launch of the UK Zehnder Academy in Camberley on…
Want to know how the whole process looks from initial quotation through design and installation to handover looks like?
We are happy to prepare a free specification and cost proposal for you.
The best MVHR system is only as good as the ducting, connected to it. We have tried and tested a number of systems.
