To get some meaningful comments, suggest you post the plan showing how many rooms, size of duct runs, where the duct runs will be. Has the house been designed to accommodate ducting? This will all have a bearing on the costs and ease for a self install.
What I did find was that of the half a dozen quotes I got, the cheaper ones just concentrated on as short a runs as possible and would have led to an inferior ventilation system,whereas the more expensive ones concentrated on getting the airflows right - the old adage - you get what you pay for

I'm not familiar with the prices of this model so can't comment on that, but the installation costs seem rather high.

You seem to be indicating that all the materials are included in the supply price of £5,500 so you are looking at £2,700 for labour only to install the system. Assuming a labour cost of £60 an hour that's 50 hours work, 6 days or so.

My experience of installing my own MVHR system was that it certainly didn't take that long but I didn't do it all in one hit so couldn't give you an accurate time, but all together probably 3 days or so.

I would have thought that an experienced fitter should be able to do it inside 2 days.

Once you are following a professionally designed duct layout for your house then I found that the actual installation work very straightforward.

Whatever you decide I would advise to install your duct early in the build before plumbers and electricians come on site and start putting obstacles in the intended path of the ducts, then seal up all the ends so you don't get any dust into them and leave it like that and commission the system when all building work is complete. We commissioned our system the day before we moved in. If the system has been designed well then commissioning should be a fairly simple task, ours took less than an hour and the cost was approx. £120 including travel time.

Any idea why they want to spec two MHRV units..? Are they both under a single controller..?

I looked at a few, and to be honest a lot of what they offer now in components are just standard items that are repurposed. For example, Airflows Zero Leakage ducting is pretty much identical to this http://www.drainageonline.co.uk/Ducting.htm if you look at it. Most of this stuff is contract moulded so copies and similar products will be very common as manufacturers want to get the most out of tooling prices and production runs.

I'd be interested to see what the thoughts on using some of the smaller (read cheaper..) units is in parallel as this seems to be where they have added cost in the past in significant jumps in pricing. Also, have they given a breakdown on what is the unit, what is controller costs etc..?

Cheers

Peter

It does worry me when ducting bends and tees are around £6-8 each, exhaust valves at less than £10, and 50m of duct is £120 that suppliers can soon get north of £1000 with cheap and cheerful plastic bits. Of all the exhaust valves I've seen, I think only 1 hasn't been based upon a threaded bolt in the centre of the fitting. The cost difference has been huge - from £6 for no name, to £11 for Lindab and up to £30 from a 'green eco store' for what was essentially a badge on a no badge unit !

Cost of being green, or just a market that's finding its watermark for pricing..? And how ethical is it to take a suppliers drawings and 'DIY' the system from the web for a third of the price..?

Cheers

Peter

Bit more than I paid for similar size building. I used the flexible (semi rigid) ducting so easily installed myself. I over specced the unit so it usually runs at less than 50% capacity - Helios EC 500 pro (IIRC). Just ordered a flow meter to set it up myself (not balanced yet and in Scotland you can do it yourself) but it seems to work pretty well 'as is'. No noticeable noise.

Thanks everyone,

Our house design is fairly long and linear (I know - not the most thermally or economically efficient shape but dictated by plot shape and orientation!) resulting in fairly long duct runs - Google gives me indicative prices for the MVHR units and controller so from the comments above I think it is the ducting costs which are surprising me (i thought to myself "basic plastic fittings - how expensive can they be?").

2 MVHR units have been spec'd because of the duct lengths (allows the duct sectional size to be kept manageable to fit with pre-planned service voids inboard of VCL/airtightness layer). I understand that this also means that units are each working at low capacity which is desirable from a noise perspective.

I'm more or less certain I'll go down the self-install route with some assistance from the trades already on site (at these install costs I may give up my day job and do this full-time!).

Ducting cost me about £1500(inc vat) for the property I'm renovating. The ducting was directly from lindab and it was there safe system (worth the extra money as it makes getting an air tight duct system easy).

Floor area is approximately 145m2 (using PHPP measuring standard) and system consisted of 5 supply vents and 3 extract vents along with several silencers. Ducting size was 160mm , 125mm and 100mm. I designed the system myself and I'm relatively happy so far. I also installed the system with my father helping and it probably took us about 2 days in total.

Only item I couldn't buy from lindab was an extract air valve with filter which i wanted for the Kitchen.

I would assume the cost saving isn't worth the hassle as there would be a far smaller range of fittings and sizes available. Also you would have to deal with adapting from PVC to the sound attenuators and then back to PVC, along with adapting from PVC pipe to the supply and extract valves.

I also think you might struggle using drainage pipe unless you have very large void/area to run pipes as even simple things like bends are available in a much tighter bend radius for proper duct systems.

I spent £1500 on lindab ducts but looking at the cost of PVC drainage I doubt you would save more than £500 as you still need to buy the sound attenuators and air valves. So is £500 worth saving worth all the issues of trying to mate too different systems together and all the extra time it might take along with the chances that it might not be possible!

I'm all for saving money but that's why I chose a quality duct system and installed it myself as this was cheaper than getting certain lesser quality systems installed by professionals!

On ducting... Anyone know if the 'ban' on flexible ducting for SAP Q includes short lengths of the convoluted aluminium tube to allow for slight offsets..?

Cheers

Peter

The twin wall 'semi-rigid' ducting seems to be a no-brainer. Airflow market it as https://www.airflow.com/zeroleakageducting and http://www.allergyplus.co.uk/ also sell it.

I'm trying to work out the difference between the ducting they sell and the stuff from http://www.drainageonline.co.uk/Ducting.htm

The airflow ducting is 75/63 outer inner and that size doesn't seem easy to find elsewhere

My point was actually that the 75/63 sold as MVHR duct should be available elsewhere cutting out a middleman and saving a chunk of cost.

Simon - think I found that stuff as well, the bigger issue is getting them to sell you just the terminals without a whacking premium !

I also found converters to do 125mm valves to 63mm pipe - may have to see if they would work out more economical. The plenum is easy to build as its just a box although I did consider sticking 4 of the hoses as tight as possible into the end of a 160mm duct and foaming them in !

Cheers

Peter

Maybe worth pricing up a system at http://www.dealec.co.uk/acatalog/vent_axia_sentinel_kinetic_e.html

Have bought stuff there in the past including recirulating cooker hood. Found them good but no other connection.