Honest reviews: Ventilation systems; which is best Dvs, Sayr or Hrv

[mrsaneperson]

I just had double glazed aluminium joinery put throughout our house in the hope it would be warmer and dryer. little did I know. The condensation seems worse than ever so I'm really interested in a HRV or whatever type system.

That intrigues me as i am a big fan of double glazing.Is it a reto-fit double glazed or completely new double glazed?

[mrsaneperson]

That's because he can buy wholesale.

The manrose fans can be bought from Bunnings cheaper than trade accounts from electrical merchants!

[north shore]

We had an hrv put in few years ago because of condensation, we have a tile roof, works well for the condensation.
We are 1/2 through retrofitting double glazing. Sometimes we have a little bit of condensation on some of the windows otherwise none.

[ivanp]

We have SmartVent in a house with concrete tiles, and there's no more water on windows...

[Suse]

That intrigues me as i am a big fan of double glazing.Is it a reto-fit double glazed or completely new double glazed?

All new.. every single window in the house popped out and new ones put in... Love the new look, just not the condensation

[Suse]

Perhaps the original poster could edit their original post to get more specific answers, ie,
what sort of ventilation system did you get
What sort of roof space/house do you have
Are you happy with it

[MAXNZ]

I just had double glazed aluminium joinery put throughout our house in the hope it would be warmer and dryer. little did I know. The condensation seems worse than ever so I'm really interested in a HRV or whatever type system.

We had our house fully double glazed a couple of years back. PVC windows.. It is an existing lockwood home, we had all old windows taken out, new windows put in. The problem of crying windows stopped, but on colder month started noticing moisture on walls in south facing rooms. Figured that installing double glazed windows turned the house into a kind of a thermos. It seemed like house was breathing a bit better with old windows. You heat the house inside and its warm and cosy, but it also kept all moisture inside as the house was completely sealed.. no breathing? and if we didn't open windows it would condensate slowly around the south side of the house interior. As with thermos... when you pour hot water in and close the lid it will condensate around the walls as moisture have nowhere to escape... Same with the house, we have sealed it with double glazed windows and doors, so moist air just stays in the house with no escape... So we decided to install a ventilation system to help with the problem. Did a bit of research and decided to go with a balanced system with heat exchange unit. Ended up with only 2 companies who could do it for us - Smartvent and MoistureMaster.

Why only 2 companies? Well I suppose due to lack of experience in such installations. As our house is a lockwood house we have no roof cavity whatsoever, so the system had to be installed under the floor with Inlet vents going into each bedroom and Outlet vent going into the lounge. Inlet vents have been installed at the floor closer to the external walls, covered with rectangular floor grills matching carpet colour. For heating and cooling the house we've got heat pump and a fireplace in the lounge. Both fireplace and heat pump sit next to the external wall. For a bunch of reasons Outlet for stale air have been installed in the lounge just above the fireplace:

0 - solid duct used outside the house to route the hot air to the core of the system
1 - to capture as much heat from fireplace as possible when its running
2 - there was no space above heat pump to install the outlet vent
3 - heat pump blows air forward so nothing to capture above it anyway.
4 - the wood burner is opposite the heat pump, so it worked out that heat blown from the heat pump will be captured as well

What we've got above the fireplace is a small stale air intake (outlet) which goes through the wall into the insulated solid duct outside which goes down the wall under the house and converts into flexible insulated duct which goes to the exchange core. From the exchange core we've got 1 duct feeding three bedroom inlets on the opposite side of the house through a couple of Y splitters. The system has got fresh air intake which is run through the damper and allows exchange core bypass for summer months... The intake is located just on the north side of the house attached to skirting.

How it works:

1. Stale air is sucked out from the house via the Outlet vent and blown straight under the house (we didn't bother ducting it as under the house is well ventilated area), the outlet vent on the heat exchange unit is grilled.
2. Fresh air is take from the outside and blown into 3 bedrooms via the heat exchange core which heats it up nicely and recovers about 90% of heat. So, the fresh air at the vents is at comfortable temperature level.
3. When the temperature outside reaches set level (e.g. 20 or 22C or whatever you set it at) the damper kicks in and fresh air supplied directly into the bedrooms bypassing the heat exchange core, so on the hot summer months we don't have to have our windows open at night to get fresh cool air inside. It also keeps house cooler in summer months when no one home as it is circulating the air all the time by sucking out stale hot air and blowing in fresh air from outside.
4. There's a bunch of filters in the system to help protect exchange core and also to help keep house cleaner. We've got standard G3 filter on the stale air Outlet and F7 filter (pollen) on the fresh air intake. Got kids allergic to pollen and noticed this summer that it helps.

Due to the difference in price between SmartVent (around $5700) and MoistureMaster (around $4700), both quoted on heat exchange systems, and more confident sounding representative we opted out for Moisturemaster system. Moisture master also promoted its own heat exchange core as a better and more efficient and longer lasting product then others. I believe it is aluminium or some sort of metal alloy core vs. plastic and paper cores of other brands. We had the system running since late last year (October or so) and it works well so far.

Pros:
Efficiency: So far it has been tested at about 8C outside temperatures. It proves to be highly efficient and supplies fresh air at 21C to each bedroom inlet (8C outside) while it's taking hot air at 23C at the stale air outlet. At the moment 23C is generated by heat pump as we haven't switched to wood burner yet.. I expect to be even better with the wood burner going as it will generate heat right below the intake..
Simple controller: It hasn't got a fancy controller but it has got all the features you need from it - temperature displays, temperature controls, timers, cost tracking, manual overrides, fan speed controls, bypass controls etc., etc.. Simple but has got everything you need.
Quite and unnoticeable: We can't hear the system at all.. it is installed under the house, the unit and all motors are properly hang. We decide to go with about 180 Sq.M capacity fan for 120Sq.M hous, we normally run it at lowest setting but tried setting to high and it is silent on both low and high. The difference in the flow from Inlets is noticeable though. Lowest setting provides plenty of flow for the size of our house. When selecting a system I suggest going larger that you need so you could run at lowest and prolong the life of the fans/motors and have spare capacity if you need in the future.
Manual overrides: allows you to shut down system completely, manually switch to summer intake/bypass, increase/decrease fan speeds etc. very flexible
Cost to run: so far we haven't noticed difference to our power bill at all.

Cons:
Fresh air: Pickup neighboring smells. It doesn't happen often as the neighbors are mostly good, but every now and then if we have certain neighbor smoking (its their visitors actually, as they don't smoke themselves) and the wind is certain direction the smells could be picked up and brought into the house. Doesn't happen often as it depends on a multiple factors (smoking, wind direction). So position your fresh air intake strategically...
Installation and unit cost: This is a bit on the higher side.. It would've been more comfortable if the price was around 3K on such a system


There was a bit of a workmanship issue which has been sorted at the end of the project (see below). Agreements have been reached and I'm very happy with the system. It completely removed all the dampness and any mould (we had a couple of spots in the south side rooms) out of the house, the house smells nice and clean (used to have a bit of damp smell), it doesn't feel damp in any of the rooms and even wardrobes, it feels dry and warm, we have no moisture condensation on any of the windows whatsoever.


A bit about the install issues, so you could keep an eye on your installer and make sure the job is up to scratch.

The first install was typical quick job... being an engineering consultant myself I'm a bit fussy about the workmanship in general and have a bit of an OCD about tidiness and compliance of various installations After the system install I have picked up multiple small things which didn't meet my expectations such as wires tangled and not loomed nicely (under the house, cosmetic issue), polyethylene strips used to support ducts (these rolled into strings and caused ducts to sag restricting the flow), not enough support points for ducts (supposed to have support every 1M or so), use of un-insulated solid duct for first leg of the stale air outlet (invalidates the point of all other insulated ducting), control box not straight (under the house, cosmetic issue), no grills on fresh air intake and exhaust of the unit (under the house, pest control). All (majority) of these have been addressed by the installer promptly on their second visit:

1. Wires were tidied up and loomed to reasonable standard
2 & 3. Polyethylene support strips were replaced with 2" wide flat support ropes installed at proper intervals (except the longest run, they replaced supports but didn't space those properly and refused to come back 3rd time so had to add 4 strips myself, no big drama)
4. External exhaust solid duct was replaced with insulated solid duct but it was rated for internal use and no cover was installed for the duct. I had to get cover fabricated for it as the duct wasn't designed for external use and was a bit fragile. I was afraid it could get sun damage, kids could damage it and also my cat started to like to scratch it too ... We have reached agreement on fabrication cost for duct cover with MoistureMaster quite easily, so no drama here either.
5. Control box straightened
6. Grills fitted to fresh intake and stale exhaust

A couple of before and after photos are at the following link, hope you see which one is which - drive.google.com/open?id=0B7Dn-KmNaP2SfmJ2Z2RrQXA5YmpwZU5QZjlSaldyZ255X2g1UDZxcXR maVAzYmw2V28yd00&authuser=0

Happy to answer any questions you might have.

[Suse]

Wow, thanks, that is a really comprehensive report. I appreciate it and will take that all on board I'm trying to do some research on the various systems, and get my head around positive pressure and balanced etc.

Our house has a roof cavity over the bedrooms, however the lounge is a cathedral ceiling with no cavity and we have a giant skylight that runs the length of the dining/kitchen area that used to lose a lot of heat, which is one of the main reasons we decided to double glaze - it morphed from double glazing that window to the whole house!. We have a large basement area as essentially the house has been built on poles being in a 100 year flood zone. The house is a lot warmer since we filled in downstairs and insulated the walls and finally put in sectional garage doors that seal it off completely. I was down in the garage the other morning and it was toasty warm!!! No windows must make a difference!
.
For heating we have a heat pump in the lounge. We also have underfloor in the bathrooms that are on timers, and other than that we might use an oil filled heater in the bedroom in the winter. I'm interested in the heat exchange, but I need to get a better understanding. I don't want to transfer heat from our lounge area to bedrooms if it will take cooking smells?

My husband is like you MAXNZ with the OCD about tidiness etc and I have a conversation with every tradesperson that comes to our house now about what our expectations are so that there can be no ambiguity. Do the job properly, don't take shortcuts and I'll pay the bill on time. I'm the confrontational type I admit... I've learnt the hard way.

I'll definitely report back on what we decide on.

PS I understand PVC windows are better than aluminium for stopping the crying windows - I wish I had known that before! You live and learn

[ivanp]

Hi MAXNZ,
1) what kind of insulation ducts are used in your system? R0.6, R1.0 or any better?
2) did you consider Cleanaire or Mitsubishi Lossnay systems?

[MAXNZ]

Hi MAXNZ,
1) what kind of insulation ducts are used in your system? R0.6, R1.0 or any better?
2) did you consider Cleanaire or Mitsubishi Lossnay systems?

Ducts:
Under the house 200mm R1.0 insulated flexible wire reinforced duct is used. Solid piece outside is Nuaire Insulated Duct NTD-204. Personally, I loved Nuaire ducts (Thermal Conductivity - 0.03 W/m.k 20mm thick, which equals = 0.666 K/W, and if I'm correct that converts to R-Value = 0.666 * 5.678 = R3.78 US which is about R0.7 NZ), the quality and performance characteristics are great as well as supplementary accessories range - brackets, fixings, joints, splitters etc... and next house I would like to do whole system using these or similar products...

Simx R0.6 or R1.0 ducts - simx.co.nz/ducting/pdf/Securimax_Ducting_Catalogue_Full.pdf - or any other brand with R1.0+ rated ducts
Nuaire products - www(.)nuaire.info & www(.)nuaire.info/IandM/671620.pdf (mind the brackets)
Also found superb brackets for flex duct if anyone interested google "The Paramount J Flexduct Hanger"

People who claimed they could do under house:

Mitsubishi
I did talk to Mitsubishi and found them very bad in communication, I had to chase them up for a quote by calling 4 or 5 times, they would never return calls, at the end of the day got a verbal quote which was ridiculously priced at over 8k.. also their exchange core is paper, and as I have done some research and also was advised by many against paper cores decided to discard Lossnay.

Energy Efficient Solutions
Proposed HEX390 core, very well priced at just over $3k (best price) but showed lack of experience in under house installs and lack of knowledge about the product. Couldn't get any information on system controls from them, just datasheet on the actual unit. HEX390 - polymer core (polymer cores have some cons), fans built into the unit (harder to change if fail), and filters aren't upgradable (stuck with EU3).

Smartvent:
Good system overall (have one fitted at parent's house and it works well), easy and aesthetically pleasing controls. But once again polymer core with its weaknesses. Price was above average for their basic 4-vent system at $5.9k. Lack of experience in under house installs.

Moisturemaster - Selected this system for install, see previous posts.


People refused to look at or install in the house without roof cavity:

Sayr
Came to do quote (even though have been told over the phone there was no cavity). Nice crowd, system looked good on paper too, but refused to do under house.

DVS - Told over the phone no under house installs.. It is good as no time was wasted on visit.

Vetl8
Refused to do under house (answered my request quickly by email). It is good as no time was wasted on visit.

Haven't contacted:
Cleanaire - can't recall as no email correspondence, but name rings the bell, so maybe called them and was refused because of no roof cavity
HRV - read lots of negative feedback about them, so discarded even from quotation list

[ivanp]

Awesome, thanks for all the information!
Cleanaire also have aluminium plate core.

As for ducting, I have Simx R1.0 in Smartvent system, but I suspect R1.0 is not enough for long runs. I didn't measure temperature drop yet, but plan to do that some time.

[johnrw]

2. Unovent has sensor controller install-and-forget called Unobrain which switches off system in summer (air temperature in roof space too high), switches off system in winter (air temperature in roof space too low) and switches off system when the roof space air gets too humid due to long periods of rain. No one else looks at this last issue.
3. Unovent filters are G4/EU4 the same as others such as DVS standard, Moisture Master and they catch particles of fibre because fibre is about 30 microns. The roof space air is not stagnant and full of nasties once a ventilation system gets going - the air in the roof space is changing 3 to 4 times more than in the house - where do you think that air originates from - outside of course and is the same air that people let in everytime they open the door - there is so much garbage talked about regarding air quality of the roof space air. The characteristics of the air in the roof space follow whatever is going on outside by a delay of only hours which is why DVS, HRV, etc, bring moisture into the house when there are long periods of rain. Unovent is smart enough to switch the system off when other systems do not.
4. Much lower cost to buy, to run, filters can be washed every two years from inside the house, fans are 14 dB(A) much lower noise than published rates on some ducted system websites.
5. Airflow in ducted systems is too high. Room changes of 0.5 to 1.5 per hour work well enough. Ducted systems typically have vent just inside bedroom doors. This is not as effective as the Unovent recommendation to put them diagonally opposite the door near the windows to be more effective at pushing all the air out of the room.

Less money for equal or better performance, no need for the nurdy gadgets on the wall called "control panel" and equal filtering to many others when the air being filtered is actually cleaner than inside most houses.

[mrsaneperson]

""MAXNZ: house inside and its warm and cosy, but it also kept all moisture inside as the house was completely sealed.. no breathing? and if we didn't open windows it would condensate slowly around the south side of the house interior. As with thermos... when you pour hot water in and close the lid it will condensate around the walls as moisture have nowhere to escape..""

just adding to this - i experienced more moisture levels in our home after we topped up with more insulation in the attic - more insulation = more moisture trapped below

[MAXNZ]

Hi Johnrw, what was #1?

2. Unovent has sensor controller install-and-forget called Unobrain which switches off system in summer (air temperature in roof space too high), switches off system in winter (air temperature in roof space too low) and switches off system when the roof space air gets too humid due to long periods of rain. No one else looks at this last issue.

Most of the systems nowadays have brains and are sensor controlled, maybe with exception of really budget ones which are ON or OFF all the time with no sensor controls (fan air exchange). While switching system off in winter is arguable (I take it Unovent is not heat exchange type), couple of other things I have noticed could be a downside - 1. switching system off in summer if roof temp too hot.... it would be better to divert and supply fresh air from outside rather then the roof in this case. This way the house is still ventilated with fresh air so no build up of stale air or moisture inside. Number of systems have this option. 2. Air gets too humid when raining - can't agree with that one... I'll explain below. And by the way new Smartvent Evolve system handles humidity sensing as well.

3. Unovent filters are G4/EU4 the same as others such as DVS standard, Moisture Master and they catch particles of fibre because fibre is about 30 microns. The roof space air is not stagnant and full of nasties once a ventilation system gets going - the air in the roof space is changing 3 to 4 times more than in the house - where do you think that air originates from - outside of course and is the same air that people let in everytime they open the door - there is so much garbage talked about regarding air quality of the roof space air. The characteristics of the air in the roof space follow whatever is going on outside by a delay of only hours which is why DVS, HRV, etc, bring moisture into the house when there are long periods of rain. Unovent is smart enough to switch the system off when other systems do not.

Agree on air quality.. filters are needed everywhere as one wouldn't want all the crap from the roof (or other space) to be sucked into the house or into the system components (fans, motors etc.). It's good to see your system uses G4, most other brands' standard filters are G3, however most can be upgraded all the way to H9 hospital grade if required. Will your system cope OK when fitted with higher grade filters (more strain on fans due to finer filters)?
Now, regarding bringing moisture inside the house when humid outside... I completely disagree with that. First of all with both our systems I notice moisture content inside the house is way less when the system is ON regardless of the conditions outside (rain or sun). The windows don't fog, no crying windows, wet sills or damp walls and it generally feels dryer with the system ON rather than OFF. Another example I can give you... is a car windscreen during the rain, it fogs up quickly unless you have ventilation going and if you have your car on internal circulation it doesn't help either, only fresh air from outside helps rid of fogging windows during rain. Ventilation helps rid of moisture, no ventilation leads to moisture build up. Introduced air forces out the moist, so why would you turn it off?

But in saying that it might be due to the nature of the systems I have, both are balanced, meaning there are inlets to allow fresh air in and also outlet to force bad (moist and stale) air out.. Not every manufacturer at the moment does balanced systems, and my understanding unovent is amongst those who don't. With positive pressure systems the air is forced through open windows and doors or through the cracks, bad seals or whatever escape it can find and with well insulated house fitted with double glazed windows it has very small escape capacity.

4. Much lower cost to buy, to run, filters can be washed every two years from inside the house, fans are 14 dB(A) much lower noise than published rates on some ducted system websites.

Had a look at the unovent website and it looks like fans and filters are fitted into each inlet, while 14DB would be whisper quite the fans are actually right there in each room where the outlet is fitted so can't compare to published rates of other systems. Other systems in comparison have fans well away from the outlets, usually fitted in line with ducting or in the system core. While they might be louder on paper we have yet to hear any of our two systems. Smartvent and Moisturemaster systems installed in two of our houses and none of them can be heard at all even on highest setting unless I actually go under the house next to the fans where moisturemaster unit is or into the roof where smartvent unit is installed.

5. Airflow in ducted systems is too high. Room changes of 0.5 to 1.5 per hour work well enough. Ducted systems typically have vent just inside bedroom doors. This is not as effective as the Unovent recommendation to put them diagonally opposite the door near the windows to be more effective at pushing all the air out of the room.

Airflow in most ducted systems is adjustable, is it adjustable in Unovent? Various systems allow from 3 to 9 step airflow adjustments... meaning good airflow control and showing that fan capacities are there in case you need it. Normally we run system on lowest setting and fans are working at quarter of its capacity which increases their lifespan. Both our systems are fitted with Summer option, meaning they take fresh air directly from outside and bypass roof intake or heat exchange core when its too hot. And when it is too hot even on summer bypass we can increase airflow so air is changing quicker and doesn't heat up inside as much, so house stays cooler.

All manufacturers I spoke to suggested inlets to be placed in the far corner of the room. In ducted systems it increases the length of duct (adds cost) and in heat exchange systems it adds to temperature loss, but there's no point in placing inlets right above or below the door as it adds no value as room air is barely circulated in this case. So, it's a good and sensible advice from Unovent.

Less money for equal or better performance, no need for the nurdy gadgets on the wall called "control panel" and equal filtering to many others when the air being filtered is actually cleaner than inside most houses.

Cost is a factor especially for investment (rental) properties. Its not bad at all for a budget DIY system to be between $900 (2 inlets) and $2000 (6 inlets). Especially when there's no ducting involved, filters are easily accessible and potentially you could run inlets on individual basis. Regarding the controller - I personally like to have all the information available (temperature readings at each sensor point, fan speed readings and controls, cost calculation, sensor set point controls) and being an engineer I like to have manual control over the system in case I want it to do something different from what it decides to do on its own... computers vs. humans .. In this regard I see potential improvements to the Unovent already - individual inlet controls, adjustable fan speeds etc... But no controls is probably better choice for rentals so no tenant mucks around with the system.. So overall looks like good option for rental properties, but not for own home unless budget is very tight. Also, living in the lockwood house with no roof cavity I say this system can't be used in such houses ...

[johnrw]

MaxNZ, send me a PM so that we can communicate directly. I am a Freshie with insufficient posts to qualify to send PM's. #1 was NZ fully owned.