Advice needed on Ventilation / Heat Recovery systems

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43 posts

Geek
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#1782771 15-May-2017 20:40

Hi Simon

We used an Auckland based business so probably no use for you in Wellington. We had a couple of quotes and both were very similar. The Lossnay only solution still requires all the ducting and outlets to install, so should be between $3k-$4k all up (way better value than a similarly priced PPV system). Adding a ducted heatpump into the system will add about $8k-$9k to the costs.

$16.5k sounds very high if it's for a similar solution and the install isn't overly difficult. It could be that they are very busy so just give you a silly price just in case you take it.

My suggestion is you shop around for another quote, look for Wellington based recommendations from this site or from places like www.propertytalk.com in the Maintenance section of the NZ Forums.

CutCutCut

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#1782860 15-May-2017 23:13

tim360:

Hi Simon

We used an Auckland based business so probably no use for you in Wellington. We had a couple of quotes and both were very similar. The Lossnay only solution still requires all the ducting and outlets to install, so should be between $3k-$4k all up (way better value than a similarly priced PPV system). Adding a ducted heatpump into the system will add about $8k-$9k to the costs.

$16.5k sounds very high if it's for a similar solution and the install isn't overly difficult. It could be that they are very busy so just give you a silly price just in case you take it.

My suggestion is you shop around for another quote, look for Wellington based recommendations from this site or from places like www.propertytalk.com in the Maintenance section of the NZ Forums.

I'm in the early stages of planning a new build and this looks like a nice system, who did you use in Auckland? Is the system you had in installed, able to operate in a modular type fashion? ie - can you have different rooms?

tim360

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Geek
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#1783239 16-May-2017 16:10

CutCutCut:

I'm in the early stages of planning a new build and this looks like a nice system, who did you use in Auckland? Is the system you had in installed, able to operate in a modular type fashion? ie - can you have different rooms?

The simplest solution for different rooms is to have inline dampeners so you can adjust the airflow to each room. For example we have a large duct going into the lounge with no dampener, however in the bedrooms we have inline dampeners which are closed a little to reduce the airflow, and therefore heat. The inline dampeners need to be as far away from the outlet vent as possible to prevent any noise of the reduced airflow. It's also great if you can access to the dampener so you can open them up for the summer time when you might want more airflow to bedrooms.

You will pay a lot extra for zone controllers which can mechanically adjust the airflow to each zone. A well balanced system shouldn't need this but I guess some houses may need zone control due to their layout or temp variations between the rooms.

I'll PM you the installer.

Paul1977

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#1791167 29-May-2017 15:27

We are looking at adding ventilation of some kind to our old 1940s era house.

A balanced pressure system with heat exchanger like Cleanaire or Smartvent Synergy sounds a lot better than a positive pressure system, but do they work well in older homes that are not nearly as airtight as a new build?

timmmay

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#1791170 29-May-2017 15:32

Paul1977:

We are looking at adding ventilation of some kind to our old 1940s era house.

A balanced pressure system with heat exchanger like Cleanaire or Smartvent Synergy sounds a lot better than a positive pressure system, but do they work well in older homes that are not nearly as airtight as a new build?

Best guess, yes should be ok, maybe not as good as new but fine. Given some vents will blow and others will suck (ahem) it's probably easier for the air to take that route rather than force out through cracks.

Probably worth waiting for someone who has actual knowledge though, rather than my thoughts.

Kickinbac

468 posts

Ultimate Geek
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#1791248 29-May-2017 17:12

timmmay:

Paul1977:

We are looking at adding ventilation of some kind to our old 1940s era house.

A balanced pressure system with heat exchanger like Cleanaire or Smartvent Synergy sounds a lot better than a positive pressure system, but do they work well in older homes that are not nearly as airtight as a new build?

Best guess, yes should be ok, maybe not as good as new but fine. Given some vents will blow and others will suck (ahem) it's probably easier for the air to take that route rather than force out through cracks.

Probably worth waiting for someone who has actual knowledge though, rather than my thoughts.

I agree with Timmay. An issue will be leakiness (infiltration) when it's windy disrupting the balanced system.

I put a Mitsubishi Electric Lossnay system in my 60's state house (house now sold). I'm in the trade and as I got it cheap as run out stock decided I would experiment. It did a good job of ventilating the house as definately reduced condensation. I'm not sure if it did a great job of heat recovery but we didn't heat the whole house as only had a heat pump and fire in the lounge (used one or the other). It was partly an experiment to see if it would also work as a heat transfer system. It kinda did but the hot exhaust air was cooled by the outside air before it got distributed around the house so not as effective as a simple heat transfer system. It would have worked better if I was heating the whole house with say a ducted air conditioning system.

An issue I found was that the system drew in smokey outside air on cold still nights, not necessarily from our fire as the surrounding neighbourhood had fires and we would be using our heat pump.

Our Lossnay didn't have a heat exchanger core bypass damper so in summer it didn't work as free cooling from outside air. Later systems (but not all) have a bypass damper so check this out as it is a good feature to have.

You may be better to install a positive pressure system and this will most likely be a cheaper solution for solving condensation issues. Do you heat the whole house or just some rooms? Unless you've been through all the issues of an old house such as double glazing, leak proofing, full insulation (walls, ceilings and floors), polythene on ground under house, energy effiicent heating etc. there may not be sufficient benefit. Even if you do all that work it's never as airtight as a new build. Bearing that in mind, they supply in filtered outside air (not dusty crappy roof space air) and do recover the heat maintaining whilst a good air change rate in the house.

As an off topic, my friends recently built a home with a spec builder and as part of the package a positive pressure system was installed. New airtight houses should have heat recovery systems not positive pressure! This just seems stupid to me in this day and age when builders should (but most don't) know better.

I've now got a 2 storey 80's house now and working through heating and ventilation issues.

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timmmay

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#1791269 29-May-2017 17:55

Problem with positive pressure is in winter they just pump cold air right into your house. I have one, I have it on a timer so it doesn't go at all at night.

Kickinbac

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#1791340 29-May-2017 19:30

timmmay:
Problem with positive pressure is in winter they just pump cold air right into your house. I have one, I have it on a timer so it doesn't go at all at night.

So will an ERV (balanced system) if the house isn't heated. A positive pressure should have a controller with temp sensor inside the house and inthe roof space. The fan should only turn on if temp in roof is higher than in the house.

Paul1977

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#1791376 29-May-2017 20:29

Surely even in an old "leaky" house the balanced pressure system and heat exchanger would be better than positive pressure?

Surely regardless of the "leakiness" the bulk of the air will take the path of least resistance, which surely would be the fan powered vents?

I don't know what the price difference is, but pretending price wasn't a factor, are there any circumstances where a positive pressure system is better?

tim360

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Geek
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#1791405 29-May-2017 21:26

Based on the prices I was given the positive pressure systems were similar in price to the Lossnay system, hence it was a no brainer to get the superior balanced pressure system.

Aredwood

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#1791414 29-May-2017 21:58

Paul1977: Surely even in an old "leaky" house the balanced pressure system and heat exchanger would be better than positive pressure?

Surely regardless of the "leakiness" the bulk of the air will take the path of least resistance, which surely would be the fan powered vents?

I don't know what the price difference is, but pretending price wasn't a factor, are there any circumstances where a positive pressure system is better?

Only situation where PPV would be better would be houses where someone is at home all day. When those days in autumn, winter, spring. Where it is sunny but still quite cold, the sun would warm up the roof space. And you could then use the PPV system to bring the heat into the house. This would work especially good if you have some rooms that don't get any sun, as you could use the PPV system to heat them.

Problem is that you couldn't use an off the shelf PPV system to do that, as their controllers are normally designed to run the fan continuously, and just vary the fan speed. While instead you want the system to run under only certain conditions. And you would still need a full heating system for the depths of winter. And you would probably need to integrate it into a home automation system. So the HA system can measure roof space temp and humidity, room temp and humidity, weather forecast, time of day ect. And then decide whether to run the PPV or your heating system. So you would have to build a system from scratch, or buy a second hand HRV or similar system and modify it. There is a thread on GZ on interfacing into the comms cable between the HRV controller and fan unit with an Arduino. So the HRV would probably be the easiest to hack and integrate with Open HAB.

Even better would be a proper heat exchanger system, With multiple dampers so intake air can be either from outside or the roof space, a bypass damper as mentioned earlier, and a damper that allows the system to recirculate inside air instead of only being able to operate with 100% outside air. As that would solve the problem mentioned earlier with the wood fire smoke. And have humidity sensors as well as temp sensors all over the system. So you can set both a target temperature and humidity levels. And probably add oxygen or CO2 sensors as well, so the system can sense how many people are in a room and adjust the amount of ventilation as needed. But such a system AFAIK isn't available as an "off the shelf" system. And would cost heaps to get someone to design and install it.

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Kickinbac

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Ultimate Geek
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#1791415 29-May-2017 21:59

Paul1977: Surely even in an old "leaky" house the balanced pressure system and heat exchanger would be better than positive pressure?

Surely regardless of the "leakiness" the bulk of the air will take the path of least resistance, which surely would be the fan powered vents?

I don't know what the price difference is, but pretending price wasn't a factor, are there any circumstances where a positive pressure system is better?

Balanced pressure definately the better solution.

Paul1977

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#1791526 30-May-2017 09:20

Thanks @Kickinbac, that was my thinking but I wasn't sure if I was missing something.

@Aredwood some good ideas, but probably far too much effort, expense, and complexity for what I am wanting to achieve.

I had Cleanaire around last night, and should get some pricing in the next couple of days from them. Only thing I don't like about their system is a lack of connectivity. They just have a hard wired on/off switch with a fan speed control. Part of me thinks that with a balanced pressure system this might be all you really need, but I see the SmartVent Synergy has WiFi connectivity for smartphone and tablet control, so another part of me thinks that I'd rather have too much control than not enough. SmartVent are coming around next week.

Between Cleanaire and SmartVent Synergy what would everyone recommend, and why?

Kickinbac

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Ultimate Geek
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#1791619 30-May-2017 11:31

Paul1977:

Thanks @Kickinbac, that was my thinking but I wasn't sure if I was missing something.

@Aredwood some good ideas, but probably far too much effort, expense, and complexity for what I am wanting to achieve.

I had Cleanaire around last night, and should get some pricing in the next couple of days from them. Only thing I don't like about their system is a lack of connectivity. They just have a hard wired on/off switch with a fan speed control. Part of me thinks that with a balanced pressure system this might be all you really need, but I see the SmartVent Synergy has WiFi connectivity for smartphone and tablet control, so another part of me thinks that I'd rather have too much control than not enough. SmartVent are coming around next week.

Between Cleanaire and SmartVent Synergy what would everyone recommend, and why?

They both are supplied by reputable companies. I can't recommend either of these but only because I have no experience with them. The Cleanaire website has some very good techincal information that I'm going to read properly tonight.

You could find a local Mitsubishi Electric dealer and see if they can help you with a Lossnay.

The Lossnay I had came with a neat wall controller that showed the inside and outside temperatures. It also shut the system off under certain conditions i.e. when it was too cold outside compared to inside and vice versa so a bit more sophistication to it's controls.

ronw

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#1791662 30-May-2017 11:44

I have a Cleanaire installed some years ago. I find it works fine for my purpose which was to get rid of moisture in the house. I have inlets/outlets throughout the house. It has a Swedish heat exchanger in the roof space. My only problem at the beginning was I had recessed lighting in lounge which left a gap around the bulbs into the roof space. The installer ripped all these outs and put in holders that were sealed. As you noted he only control is a rheostat switch and an on off switch. I tend to turn it off in summer.

The only downside is servicing. I have a very small space for entry into the roof area so it needs someone young and agile to go up there to replace the filter and clean out the exchange.

It doesn't seem to have too much dirt on filter so I tend to let it go for a couple of years. I live in Auckland and the original installer has long gone but I have not yet found an electrician that understands the system that is willing to come and service. What area are you in?

I had Cleanaire around last night, and should get some pricing in the next couple of days from them. Only thing I don't like about their system is a lack of connectivity. They just have a hard wired on/off switch with a fan speed control. Part of me thinks that with a balanced pressure system this might be all you really need, but I see the SmartVent Synergy has WiFi connectivity for smartphone and tablet control, so another part of me thinks that I'd rather have too much control than not enough. SmartVent are coming around next week.

Between Cleanaire and SmartVent Synergy what would everyone recommend, and why?

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