Insulation without ventilation leads to dampness issues

[Learning]

We're discussing positive air pressure systems on page 5 in the mould on mattress thread in Tenant stuff.

[charlotte30]

Sorry Davo, I do not know much about them to explain in detail why it has to be a positive pressure system. All I know is this is what works.

[ivanp]

My preference is for SmartVent:
- SmartVent SV04 costs about $1600 if self-installed, good for any 3-bdrm house.
- SmartVent SV02 + an extra outlet is about $1180 - good for 2-bdrm units and minor dwellings.

Both are straightforward to install, use standard components (such as 150mm ducts, ceiling outlets, etc) that are widely available, and can be upgraded later if needed - such as a heat transfer option, etc.

I've got two Unovents as well, but their current retail price is ridiculously high in my opinion (I've bought earlier in 2015 with APIA discount, the price was more reasonable back then). Unovent is easier to install, but I think that their controller is too simplistic for the price paid. It switches off when roof space cools down to +8C: i think it should be adjustable - I'd prefer it to stop blowing at +12C or so.

[Davo36]

charlotte30 why do you need a positive pressure system? Or are all these systems positive pressure?

[charlotte30]

HRV are at the top end of price in my opinion. I used DVS a few years ago and found it a lot cheaper than HRV. Products were similar. To me the question is, does it do the job and how much?. I think you can get bamboozled with too much detail.

[north shore]

Thanks Charlotte, Too much choice now, it gets confusing.
We were told $3300 for our 2brm rental 70sqm from hrv, around $2800 from sayr

[charlotte30]

Price and builder recommendation (He has 20 rentals). It is around $1600 incl GST installed. I looked at Unovent (recommended by PIA) around $989 for a self install.

[drelly]

HRV wanted to charge us $6k for our house. I'm sure there's a cheaper option for a fan and some pipes!?

[north shore]

Hi Charlotte, could I ask what made you choose Drivaire? There is certainly a lot of choice out there now.

[Wayne]

so am investigating a ventilation system so am interested to see what other people with the same situation have gone with...

Open the windows for a while during the day?
We had streaming windows last week with all the rain in Hamilton and being shutup during the day.
Nice weekend, 1 day of airing and no more wet windows.

[FrozenWaves]

I am just going through this with our PPOR which is a 50's weatherboard house.
Insulated ceiling and underfloor and now we have condensation on the internal exterior walls and water running down the windows since the temps have dropped. Mildew has already stated to form as a result ,so am investigating a ventilation system so am interested to see what other people with the same situation have gone with...

[charlotte30]

Drivaire 2 outlet ventilation system. The flat is 90sm with an attic bedroom. Using it for downstairs bedroom and lounge living area.
Cheers
Charlotte30

[drelly]

Agree withe the above. My experience with renovating a 100 year old house and insulating ceiling, walls and inter tenancy walls, has been condensation problems when winter came. [/COLOR](House split into 4 flats) One unit faces North and the water literally runs down the windows.  A dehumidifier is being used by the current tenants which works well. I will install a positive pressure system in the next few weeks and this will hopefully solve the problem.

What system are you putting in?

[TheFlash]

Yeah, i got the old paper fluff in the ceiling. and then some bats were added to a portion of the roof. If a little bit of water gets through the tiles the paper fluff would grab it and it would eventually evaporate out. The bats dont hold water but force it to the exteriour of the walls if the ceiling is on a angle so a behavour change - so old house mixed with new products - cant be a good thing.

[Davo36]

You need advice from an expert - Twyford or Little.

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