Mechanical heat recovery MHVR

[Matt8500]

Looking for any advice or recommendations for installing an MHVR system in an existing house. With energy prices on the up the time has come I think to install one. We have a log burner and free wood, so am hoping it will not only reduce heat lose this winter but also distribute the heat from the burner round the house.

Does anyone have any experience of doing this? Thanks!

[MonkeyBoy]

We are currently installing one on a new build so understand some of the practicalities. Retrofitting on an existing property could be difficult, the diameter of our pipes range from 125 - 150mm. Systems with narrower ducting are available. Such systems are designed for use on airtight/passive type houses and as such I don’t think are suitable for your intended use.

I would recommend talking to the Green Building Company about your requirements (not used for MVHR but supplied and fitted my triple glazing) as they are very approachable and knowledgeable.

[Wimm]

I attempted an eco retrofit of a Victorian mid terrace a few years back and all the advice I was given is that, before you start adding flashy systems, you need to get the building reasonably air tight and well insulated first (the call it the Fabric First approach). So we focused on this (doubled up insulation in loft, insulated floor slab with UFH and modern, insulated extension to the back) and it was pretty successful and I reckon we took a third off of our energy usage (two years ago I was paying £55/month in total, partly regretting moving).

Another recommendation for the Green Building Store. We approached them for advice and they were very helpful (we did pay for some of it). We also bought triple glazed doors from them which were very good.

[demonloop]

In the midst of a new build here too, and as the others have said, you need a fair degree of air tightness to get the benefits and given the amount of ducting I'd think retro-fitting would be very expensive and intrusive

They're quite affordable now, but much easier to fit to a blank canvas

[Matt8500]

Thanks all. We live in a bungalow so running the ducting is easy. I’ve been slowly insulating and draft proofing the old part. The newer parts are built to modern standards so overall should be ok. The main drafts are from trickle vents and extractors now which I will seal up.

[hawkit]

A lot of it depends on the type of property you have.

We've are just coming to the end of a two year build remodelling and extending a 700 year old property, we looked in to these systems, got lots of advice, and whilst it was possible to spend the money to make the property air tight enough to make it efficient, the advice we got it would be detrimental to the old part of the property as they are designed to breathe, no dpc, 2 ft thick stone walls etc, so we had to find a balance between the massively insulated new parts and the old fabric so to avoid moisture build up etc, so in the end the systems wouldn't of been suitable and we ensured that the old part of the building was stripped of all modern plasters etc to allow that part of the building to function without the "modern" solutions which have massively damaged these old properties in the past

[ernestrome]

Thanks all. We live in a bungalow so running the ducting is easy. I’ve been slowly insulating and draft proofing the old part. The newer parts are built to modern standards so overall should be ok. The main drafts are from trickle vents and extractors now which I will seal up.

How have you done this? Are all the seams taped?

[Matt8500]

How have you done this? Are all the seams taped?

Each room was different , but main issues where floorboards, under skirting, badly adjusted windows and doors, and light fittings. Now it’s the vents /extractors which are needed until I fit a system.

[ernestrome]

Each room was different , but main issues where floorboards, under skirting, badly adjusted windows and doors, and light fittings. Now it’s the vents /extractors which are needed until I fit a system.

If be interested to hear more details if you have time as i would like to do the same to our house, gradually improving the insulation and air tightness. Unfortunately for us i think ceiling plasterboard on the sloping roof sections of our bedrooms and possibly also the dwarf walls might have to come down to make cut down the biggest losses, as well as revising the dormers.

[Matt8500]

If be interested to hear more details if you have time as i would like to do the same to our house, gradually improving the insulation and air tightness. Unfortunately for us i think ceiling plasterboard on the sloping roof sections of our bedrooms and possibly also the dwarf walls might have to come down to make cut down the biggest losses, as well as revising the dormers.

Happy to chat, PM me and we can sort a suitable time.