DVS vs HRV (home ventilation)

[Oakie]

Had a DVS for 17 happy years and it needs to be replaced. Doing due dilligence and must consider an HRV system as an alternative. Thoughts or experences anyone? Oh, $1995 for the new system which is OK as the orginal one cost me $1700 odd way back when.

[sidecar bob]

We have a window, we often open it. Ten years it's been so far & the house is still very dry.

[austingtir]

No complaints about my HRV.... The filters could be cheaper though but I hardly ever change it so whatever.

I can say there is an amazing difference between an open window and an HRV.

My coffee table bowed after we moved into this house 10 years ago after a house without one.
I think if you've never had one before you would not know the difference. Its a big difference I wouldnt own an older house without one now.

[caspernz]

We've had both HRV and DVS in different houses. Same thing basically.

For best results, combine with a heat pump and learn how to use them in clever tandem.

[russd7]

they are both pretty much only a fan with cheap filters and some ducting, as has been said already, open some windows.
last place we lived in had an hrv and it was as useless as tits on a bull until I took the filters out and converted it in to a heat transfer system, was much more useful

[BMWST?]

we have a drivaire system.It can be configured to use as a heat transfer system,or on a hot summers day to draw cooler air from the back of the house(in the shade in the evening), to help cool the house.They can be much more than a ventilation system.
They work.On the first day our system was installed the windows were absolutely running with consdensation,the next day yhe condensation was halved,the next day there was none.The only time we get condensation on our windows now is if there is quite a rapid temeperature drop and then it is just a light mist.
I would get a ventilation system in a new house now.

[mulletman]

we have a drivaire system.It can be configured to use as a heat transfer system,or on a hot summers day to draw cooler air from the back of the house(in the shade in the evening), to help cool the house.They can be much more than a ventilation system.
They work.On the first day our system was installed the windows were absolutely running with consdensation,the next day yhe condensation was halved,the next day there was none.The only time we get condensation on our windows now is if there is quite a rapid temeperature drop and then it is just a light mist.
I would get a ventilation system in a new house now.

^^^^^^^^^ This

I have a similar set up from

http://www.hypervent.co.nz/

[sidecar bob]

No complaints about my HRV.... The filters could be cheaper though but I hardly ever change it so whatever.

I can say there is an amazing difference between an open window and an HRV.

My coffee table bowed after we moved into this house 10 years ago after a house without one.
I think if you've never had one before you would not know the difference. Its a big difference I wouldnt own an older house without one now.

I doubt our modern North facing sun trap could be any drier. I'm sure they have their place though.
Our house also has no ceiling cavity in about 80% of it, so a bit hard to install anyway.
I checked the coffee table & it's fine, the glass is still completely flat.
I did a bit of relief work as a postie recently & the amount of houses with all the windows & half the curtains shut that are soaking wet on the windows & probably everything else inside is astonishing.
Healthier homes mainly require people to be educated more than anything.

[austingtir]

I doubt our modern North facing sun trap could be any drier. I'm sure they have their place though.
Our house also has no ceiling cavity in about 80% of it, so a bit hard to install anyway.
I checked the coffee table & it's fine, the glass is still completely flat.
I did a bit of relief work as a postie recently & the amount of houses with all the windows & half the curtains shut that are soaking wet on the windows & probably everything else inside is astonishing.
Healthier homes mainly require people to be educated more than anything.


Well there you go I could leave all the windows shut and all the curtains shut ALL YEAR and have zero damp issues. And I also have zero dust to clean up or pollin getting in.

But your right about the house design if it doesnt have a roof thats going to generate some warm dry air in that space you would certainly be wasting your time installing one.


The difference between having a house with air constantly circulating and one without is night and day. Try opening the windows mid winter to dry your house out. If you think your drying your house out at that time of year with a window open your bloody dreaming.

[neels]

There is a HRV system in one of our rentals which seems to work very well at keeping the place dry and mouldless.

When I was working on the place over summer I discovered one feature that it has, that after some research I've found some others don't, it works on both heating and cooling. It works pretty well in the morning to warm the house up once the outside air temp is above the set point, but is even more useful in the evening when outside cools down below set point and it switches mode to cool the house. I'm tempted to get one for our place just for this function, our upstairs bedroom gets hell warm in summer so cooling it down with just a 100W fan using cool air from outside would make sense.

[jellywrestler]

I doubt our modern North facing sun trap could be any drier. I'm sure they have their place though.
Our house also has no ceiling cavity in about 80% of it, so a bit hard to install anyway.
I checked the coffee table & it's fine, the glass is still completely flat.
I did a bit of relief work as a postie recently & the amount of houses with all the windows & half the curtains shut that are soaking wet on the windows & probably everything else inside is astonishing.
Healthier homes mainly require people to be educated more than anything.

i do install work for DVS and most are oversold, they are great for older properties with drafty dorrs and windows as they pressurize the houses and sttop fresh moisture laden ground level air coming in, the benefits stop when you have well fitting windows etc. the biggest rort is upgrading $1995 for a new fan and controller, yip the gear is nice but not worth anywhere near that.

[BMWST?]

i do install work for DVS and most are oversold, they are great for older properties with drafty dorrs and windows as they pressurize the houses and sttop fresh moisture laden ground level air coming in, the benefits stop when you have well fitting windows etc. the biggest rort is upgrading $1995 for a new fan and controller, yip the gear is nice but not worth anywhere near that.

they have a valuable function in more modern airtight homes too.The problem with more modern homes is that they are so airtight that you may need to have some vents installed in say your double glazed windows to let the warm dry from your roof OUT you then get much of the same benefits as in older homes.Any if there is a lack of proper ventilation for your showers,wet washing hung up inside,etc etc then a ventilation system will deal with that.You are right tho the cost of these systemes far outweigh the cost of the componenets!

[Oakie]

Thanks for the comments.

Opening a couple of windows at the correct time of day (something to do with the dewpoint) to create a drying draft will help but of course lets the cold in.

We originally got our DVS because of condendsation on our 1970s house. We were told the overpressure would drive the moisture out and stop condensation "in a short time" That 'short time turned out to be one day as the morning after the system was installed there was no condensation. It was a stunning improvement.

I don't see where the $1995 goes but I guess it is what it is.

[jellywrestler]

Thanks for the comments.

Opening a couple of windows at the correct time of day (something to do with the dewpoint) to create a drying draft will help but of course lets the cold in.

We originally got our DVS because of condendsation on our 1970s house. We were told the overpressure would drive the moisture out and stop condensation "in a short time" That 'short time turned out to be one day as the morning after the system was installed there was no condensation. It was a stunning improvement.

I don't see where the $1995 goes but I guess it is what it is.

that 1995 was just a new motor and controller into existing duct work.
most bathrooms are fucked up, fans, but no way to let air into the room so the fan can remove it, pretty soon you either leave a window open when there should be a vent usually in the door, also fans with timers are a great move, rangehoods are good, easier to put the lid on the pot though.

[Drew]

For the price you pay, ya get fuck all hardware.
I used to install similar stuff, they're a fucken rip off.

[sidecar bob]

You could call it Trevor, it's still just a ducted fan, not some kind of magic beans.

[Oakie]

You could call it Trevor, it's still just a ducted fan, not some kind of magic beans.

But it has pretty LEDs to look at...

[austingtir]

But it has pretty LEDs to look at...


And makes a soothing noise in the middle of the night like your at an expensive hotel!

[TheDemonLord]

Bump.

Just wanted to give some Props to Bevan at DryLiving.co.nz - I've been on the hunt for a system that will work in my house (Although Jelly suggested a number of fixes that I should also implement) - and he put me onto something that I was looking for, despite it not being a product he carries or installs.

I always like to give credit to businesses who will point the customer towards what they need rather than what they can sell them.

Top Bloke.