MEV or MVHR

[70sbrick]

Hi all

Would love to get your views on this.

We're upgrading our early 1970s detached house, with (as a minimum) cavity wall insulation, insulating under the suspended floor, upping the loft insulation and replacing doors and windows with triple glazing (Rationel / IdealCombi / Norrsken TBC). We may also insulate walls externally (subject to cost / budget).

We're also building a kitchen extension which will be heavily insulated and airtight.

We're now looking in to installing either a MEV or MVHR system.

We've got supply only quotes from BPC of £2150 for MVHR and £575 for MEV, with extract from 3 bathrooms (upstairs, downstairs and en-suite) and the kitchen.

We've got a young family and both work pretty much full time, so we're only really in the house at weekends and evenings.

In summer / warm spring days the doors into the garden will be open, so lots of air will be drawn into the house.

I know there's the thinking that MEV is throwing away money, extracting warmed air, but surely it would take a long a time for this to add up to the £1500 difference in supply cost, plus probably that again in installation cost.

Heating is standard central heating from a combi boiler.

My current thinking is that MEV would give the benefits of quiet extraction of moisture and odours from the bathrooms and kitchens and avoid the need for wall extractor fans, and its hard to justify the additional benefits of MVHR given our use of the house.

It would be really good to hear from anyone who has a MEV system installed, or who upgraded from MEV to MVHR.

 

Thanks!

 

[Iceverge]

I installed a Domus MEV unit in my parents house from BPC. 

 

It has reduced the humidity but we'll have to wait until the winter to see what the true benefit is as the weather has been quiet dry since. I wasn't overly impressed with the unit. The fans were noisier than I expected and the ducting was difficult to fit well.

 

From your situation it is indeed difficult to see huge benefit from MVHR. I would be careful with the spec of ducting supplied with MEV however as often it can be the floppy stuff that may end up being noisy. 

 

If retrofitting MVHR supply ducting is too difficult you could always just install a MVHR unit as an extract only and dump all the fresh air into a single hallway or similar. You'd get most of the benefit of the recovered heat with less if the hassle and expense.