Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

6 posts

Wannabe Geek

# 252957 18-Jul-2019 19:31
Send private message quote this post

Firstly wanted to preface this by saying that I have spent quite a while looking through all the great previous discussion around the various options to achieve effective home ventilation and really appreciate everyones input.


We live in a 1960's weatherboard house with leaky single glazed wooden joinery. We have ceiling and underfloor insulation and are planning on replacing the existing joinery with new double glazed units in the next couple of years.


The internal relative humidity level in the house ranges between 60-80% at 18deg depending on which room we are measuing in (we live in Auckland), we have a little bit of mould on some curtains in one of the bedrooms and obviously condensation problems which are to be expected with the single glazed joinery.


The house has a Simx HeatTrans system installed with a single inlet in the lounge (fed by the heat pump) and outlets in each of the three bedrooms. We literally never use this system as we set the heat pump to 19deg in the lounge and don't generate enough excess heat as we would if we had a log burner for example.


I wanted to investigate whether we could convert the existing heat transfer system into a SmartVent ventilation system as I understand a lot of the components are very similar (we already have the outlets in each room and insulated ducting running from the inlet to each of them as well as a fan). I figured we if we converted it to a ventilation system at least we would get some benefit from it rather than the system just sitting there serving no purpose! We have loose fill insulation in the ceiling and it is fairly dusty up there so I would prefer to pull air in from outside instead of the roof space. The obvious downside of this is that the outside air will cool down the rooms a lot (although it would achive the desired reduction in humidity).


Due to this, I was interested in a balanced heat recovery type system like the SmartVent Synergy system. I called up SmartVent today and had a chat with who I assume was a sales type person there who said that they very strongly advise against a balanced ventilation system in a house built prior to 2006 and that it "would not work, even on a renovated house as it still won't be sealed enough". Now I can understand that it would definitely work better in a modern sealed house, but surely it is still better to recover 70-90% of the energy from the stale air as it exits rather than pulling in cold air directly from outside, even in a house that isn't fully sealed? Does anyone have any recommendations or any other comments?



Create new topic
5572 posts

Uber Geek

  # 2279221 18-Jul-2019 19:54
Send private message quote this post

With leaky 1960s joinery and construction, there is probably enough natural ventilation through the building that a forced ventilation system is redundant.

15207 posts

Uber Geek


  # 2279230 18-Jul-2019 20:12
Send private message quote this post

Balanced ventilation typically means one with a heat exchanger doesn't it? Otherwise you're talking about positive pressure.


Either way I think you'll see benefit from it, reducing moisture, but also making the house colder. Just run it on a timer like I do, middle of the day for 2-4 hours in winter, plus a bit after dinner, and summer mornings and evenings. Mine is just a fan, a big box filter, and a couple of outlets running on a Mitre 10 timer. My outlets are in the hallway to the bedrooms and in the kitchen. I wouldn't run positive pressure in bedrooms at night all night - once the room has been ventilated during the day maybe you won't need to.


I had loose fill wool insulation. When I put pink batts over the top it made a good difference to the heat retention - as much as putting the loose fill wool in - but this was a few years after I got the loose fill and it had compacted. Double glazing hugely reduced our condensation as well, but we didn't run the ventilation system at night so it wasn't helping.


Of course you should heat your house and remove moisture at source. 19 isn't very warm but it's a lot better than ambient - our house is around 22 usually.


6 posts

Wannabe Geek

  # 2279269 18-Jul-2019 20:36
Send private message quote this post

Yes, it is my understanding that balanced ventilation systems have a heat exchanger. This is the type of system that the person at SmartVent said wouldn't work in an older house.


Perhaps I should just start with converting my heat transfer system into a positive pressure system - all I would need is a filter and a bit of extra ducting, an outlet in the soffits and something to control it with. We have a bunch of Home Assistant stuff already so it would be super easy to just switch the fan on and off with a wifi plug. Could even tie it into some humidity sensors if I wanted to be fancy. Running it on a timer would definitely reduce the cooling effect of having it running all the time. This would definitely be a lot cheaper than a system with a heat exchanger.


Yeah we have batts over the top of the loose fill insulation as well. Unfortunately there are large gaps around the existing LED downlights though so I bet a lot of heat is escaping through there. They are definitely IC rated so not sure why they were left without insulation cover - perhaps the batts were fitted before the downlights were replaced with LEDs...

15207 posts

Uber Geek


  # 2279273 18-Jul-2019 20:43
Send private message quote this post

Filter box - something like this. I wouldn't bother with sensors, just ducting, filter, fan, and timer.


Big advantage of balanced is the outgoing air is warms the incoming air in winter, so you're pushing warmer air in. That way you'll be able to run it longer and at night. No idea if it'll work in an older house, but once double glazed... probably better than just pushing air in. More expensive though.

Create new topic

Twitter and LinkedIn »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

News »

Major Japanese retailer partners with smart New Zealand technology IMAGR
Posted 14-Oct-2019 10:29

Ola pioneers one-time passcode feature to fight rideshare fraud
Posted 14-Oct-2019 10:24

Spark Sport new home of NZC matches from 2020
Posted 10-Oct-2019 09:59

Meet Nola, Noel Leeming's new digital employee
Posted 4-Oct-2019 08:07

Registrations for Sprout Accelerator open for 2020 season
Posted 4-Oct-2019 08:02

Teletrac Navman welcomes AI tech leader Jens Meggers as new President
Posted 4-Oct-2019 07:41

Vodafone makes voice of 4G (VoLTE) official
Posted 4-Oct-2019 07:36

2degrees Reaches Milestone of 100,000 Broadband Customers
Posted 1-Oct-2019 09:17

Nokia 1 Plus available in New Zealand from 2nd October
Posted 30-Sep-2019 17:46

Ola integrates Apple Pay as payment method in New Zealand
Posted 25-Sep-2019 09:51

Facebook Portal to land in New Zealand
Posted 19-Sep-2019 18:35

Amazon Studios announces New Zealand as location for its upcoming series based on The Lord of the Rings
Posted 18-Sep-2019 17:24

The Warehouse chooses Elasticsearch service
Posted 18-Sep-2019 13:55

Voyager upgrades core network to 100Gbit
Posted 18-Sep-2019 13:52

Streaming service Acorn TV launches in New Zealand with selection with British shows
Posted 18-Sep-2019 08:55

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.