Whole house ventilation / heat recovery system

[oscar21]

Ok, we are currently about to re-wire a fire damaged house and it has a fair bit of ducting running round the building, or did have. Downstairs has a duct in the kitchen, living room and downstairs toilet, two ducts then run upstairs (I think the kitchen and toilet are teed in together and the living room has its own.
however once we get upstairs I haven't got much info to go on. This is one of the ducts downstairs.

Then the cupboard upstairs, you can see the two pipes behind the cylinder.

But you can see my problem with upstairs.

I've asked for a spec sheet and have been told its impossible, they would have to go through at least 10 different people and no-one would know any answers so the best they have come up with is have a look in a neighbouring property. I did manage to have a quick look in next door as I caught them going out and they obliged, there are also vents in all 3 bedrooms.

I have also managed to work out that there are 3 extra 1 gang switches, one in the kitchen, one in the downstairs toilet and one outside the bathroom that I think were linked together in parallel (so two browns in COM and 2 blues in L1) I'm guessing there are some kind of boost switch for the fan.

So my long winded question is is this likely to be a heat recovery system as opposed to just a central fan set up due to having vents in every room and what powers it, does it just have a permanent feed to the unit in the loft which runs on permanent trickle and the switches boost it up, there isn't a MCB for it in the mains unit.

Or would you knock on next door and say can I snoop round your loft and I promise I'm not the drugs squad.

 

[littlespark]

Don’t do the job on a price if you can’t get answers to even the simplest questions.

If a heat recovery unit is going back in, it’ll no doubt be a much more beefed up version than what was there before.
The unit could be bigger, the ducting bigger, and insulated

 

[plugsandsparks]

From the sound of it, looks like heat recovery, i.e. Kitchen, bathrooms go into extract side of MVHR and bedrooms, living room is the pre-heated fresh air supply.

 

[oscar21]

Don’t do the job on a price if you can’t get answers to even the simplest questions.

If a heat recovery unit is going back in, it’ll no doubt be a much more beefed up version than what was there before.
The unit could be bigger, the ducting bigger, and insulated

Luckilly I won't be responsible for things like the actuall fitting of the unit, My job is to connect up what is fitted, I just want to make sure I have the correct cables in at the first fix. The house has just had new solar panels fitted and all I have to do is run a 2.5 up to the isolator and connect it in. All I can really do is advise the lads on site what to do.

As for upgrading stuff, the insurance companies only want it putting back to how it was, they are quite happy for a Dual RCD board to go back in if it was there before, the less spent the better as far as they are concerned. Its the the insurance companies problem if stuff doesn't meet the latest building regs then.

 

[oscar21]

This setup is finally back working again, we managed to get into next door and have a look at theirs, I couldn't get a proper picture but the ducting looked like this

Someone else jumped up and got the details of the unit, Nuaire said it was defunct and sent the up to date version of it, the builder fitted it and all the ducting and I wired it up. When I read the instructions (after it was all fitted) one line in the book said "we don't recommend fitting this unit in a loft". It was about 3ft square and weighed about 20Kg, where is it supposed to go? on the kitchen worktop?

Now about the costs involved, I know I posted a slightly facetious comment about something green the other day but come on, the unit was £800, the ducting was about £350, a day for the builder and my time wiring it all up with switches all over the house.
Probably a couple of grand all in all to get it running, how are you ever going to make £2k back by extracting the heat "lost" from the bathroom and kitchen fan, maybe if you live to about 5000 years old you may have half a chance but I reckon the unit will be toast in under 10 years. When I went into next door I tried the switches and I couldn't hear any fans ramp up, the tenant didn't even know what the switch did until I expaline dit to her, the houses are only 10 years old or so.

Anyone who falls for all this green stuff needs to see a head doctor in my opinion.

 

[freddo]

I would have thought MVHR was about having a pleasant, not stuffy house to live in, rather than anything to do with being green. With newer houses being extra sealed, good ventilation is important.

I do have to agree seeing the internal construction of some of these units and often wondered why the cost is so high when most of the construction is just flimsy plastic mouldings and one or 2 small motors.