Jump to content

HRV


Zabman

Recommended Posts

A heat transfer kit will actually increase your condensation so they cause more problems than they solve.

The HRV is kinda expensive but the others have a lower qual filter which allows some harmful fibres from the roof into the home. glass fibres can get down to 1/1000 mm so unless we wanna breath in that stuff it pays to go for the good unit.

Link to comment
Share on other sites

  • Replies 51
  • Created
  • Last Reply

Top Posters In This Topic

This is my understanding and experince. They take the warm air from your ceiling which has been heated by the sun's ray's and move the air around your house. I would recomend that you have the in line heater option with it, because if the air temp drops in your ceiling space you get the cold air coming down through the vents. I belive that all the systems are much the same HRV, Moisturemaster, DVS, the other and most cost effcient that I know is Home Tech. My parents have just put one in after having a DVS at there last two homes. The DVS was going to cost just over the 4K mark for a three bedroom house the Home Tech was $2,300.00 installed. Works well.

They are not a heating option for your house, as on full heat they work on 4Kw only. You will need some other form of heating, heat pump's, gas, fireplace, etc...

New homes with alumium windows have vent holes, as this was a major problem when they first came out many years ago.

I hope this helps.

Regards Mal.

Link to comment
Share on other sites

We have the inline heating system with our HRV and it is excellent, however, since putting the HRV in, we have only used it once or twice to give it a whirl to see how it is, it is excellent.. however we haven't needed to use it, saving it for a real cold snap through winter if need be, just having the HRV itself running warms the house, more so than what it used to be without the system, as we no longer have that damp cold feeling in the place. I tell you how you really notice, since coming in late at night from being out or through a real cold day, you go into your home and warmth hits you, this is without the heating option of HRV being used, it is just the normal system running, all that cold damp air no longer exists and the house is so much more comfy..... No mould... no clogged up feeling, air is fresh... walls and window sills are dry... definately if you can afford it, it is money well spent... DVS, HRV.. anything similar.

Link to comment
Share on other sites

You can get a fire, installed, for similar to that $3000 HRV system...

Replacing the open fire with a fire box completely changed my place, the down side was all the woodwork that opened up as the moisture was drawn out.

Link to comment
Share on other sites

the down side was all the woodwork that opened up as the moisture was drawn out.

:lol: :lol: :lol: same thing happened to me. We had a Kent Log Fire and all our wallpaper split as the gib board dried and shrunk. It was so efficient most of the time we were too hot!!!!!!! I just got sick of hauling firewood around and wood is expensive unless you are young and fit and can collect/cut your own.

Link to comment
Share on other sites

A heat transfer kit will actually increase your condensation so they cause more problems than they solve.

What's your logic for that?

They don't add any moisture to the air themselves. Unless you're using something like an unflued gas heater that dumps massive amounts of water into the air, if you're pumping warmer air into a cold damp area it would drop the relative humidity=less dampness.

Certainly preferable especially over the winter where the roofspace is only slightly warmer than outside anyway.

Link to comment
Share on other sites

Bilbo wrote:

A heat transfer kit will actually increase your condensation so they cause more problems than they solve.

What's your logic for that?

As air heats up in the lounge with the fire going, the air increases its ability to absorb moisture. The warm room is often where every one is watching the telly and with cups of coffee and breathing and dinner steaming on your lap. That room becomes quite humid and the air holds the moisture. That warm moist air is sucked out of the room and blown into a cold room. The air then looses it ability to hold the moisture as it cools down and water lands on the coldest surface.

To compound the problem, in a room with a fire there is usually very little air movement and as we all know that warm air rises, so the air at the top of the room is hotter and wetter.

The ducted systems are very inefficient. They loose close to 70% of your paid for heat before they get to the bedrooms.

if you're pumping warmer air into a cold damp area it would drop the relative humidity=less dampness

Colder air has less humidity not more. It will temporarily reduce the moisture you see because that moisture becomes airborne.

Link to comment
Share on other sites

As air heats up in the lounge with the fire going, the air increases its ability to absorb moisture. The warm room is often where every one is watching the telly and with cups of coffee and breathing and dinner steaming on your lap. That room becomes quite humid and the air holds the moisture. That warm moist air is sucked out of the room and blown into a cold room. The air then looses it ability to hold the moisture as it cools down and water lands on the coldest surface.

To compound the problem, in a room with a fire there is usually very little air movement and as we all know that warm air rises, so the air at the top of the room is hotter and wetter.

The ducted systems are very inefficient. They loose close to 70% of your paid for heat before they get to the bedrooms.

Colder air has less humidity not more. It will temporarily reduce the moisture you see because that moisture becomes airborne.

Exactly my point. As you warm the cold room the humidity drops and dries everything. It definitely hasn't been my experience that making the rest of the house nice and warm also makes it damp.

I'll have to check, but I seriously doubt my heat transfer is losing 70% of the heat, but I haven't checked if the outside of the insulation is warm.

Link to comment
Share on other sites

The amount of water vapor the air can hold increases with temperature. Relative humidity therefore decreases with increasing temperature providing the actual amount of water vapor stays the same.

Absolute humidity (The mass of water vapor in a unit volume of air. It is a measure of the actual water vapor content of the air) doesn’t change with temperature unless the RH gets over 100%

Dew point is the when the air has cooled of enough for the RH to increase to 100% and saturation occurs. At this point the some of the water is released from the air and forms dew or condensation.

As an example.

A lounge temperature is 30c and the air is holding 30g of water per m3 if that air is cooled to 10c (by passing it through a pipe and fan into a colder area) then the same volume of air can now hold only 10g per m3, what happens to the other 20g of water?

It forms dew and by doing that it decreases the amount of water in the air. Relative humidity increases but absolute humidity decreases.

That is where condensation comes from.

Link to comment
Share on other sites

I say avoid the hrv - mum got one, in the morning its bringing cold air into the house from the roofspace, so you have to heat the house. By the time the roofspace is warm, everyones gone out so its of no help

In the afternoons, the roofspace cools well before the house, so the only useable hours are when there isnt anyone there, so the house is closed up and theres nowhere for the air to vent out.

And they never turn off, the fan just cuts back, so even in the middle of night you get a small amount of bloody cold air blowing into the place, which is pushing the heated air out somewhere else.

Link to comment
Share on other sites

I say avoid the hrv - mum got one, in the morning its bringing cold air into the house from the roofspace, so you have to heat the house. By the time the roofspace is warm, everyones gone out so its of no help

Hmm well then tell me why our house is so much warmer since having one installed :lol: It is like living in a different house since having it put in.. no damp cold air.. it is the dampness that is the killer, and mould, dust mites... gone...

Link to comment
Share on other sites

  • 2 weeks later...

Cool Tiny!

I also opted to get it installed, but neglected to add an update as to how its going!!! Its been in for a little under a week, and the condensation on the windows is almost at zero all day but we still get some in the kitchen whilst cooking!

Some doors that seem to swell and not close fully now close nice and cleanly and we have put that down to the HRV system.

Although there is no heater in the system, we haven't needed one and haven't had one going since it was installed.

On top of all that, my personal experience with the service was brilliant.

Link to comment
Share on other sites

Well I have just signed up to have HRV installed having read this thread. I will be interested to see how it goes. My house gets loads of sun but has big condensation/mould problems so it sounds like it will be a good candidate for it.

It will solve that, but ignore any claims they make about the place being warmer, because you have to re-heat the air to make up for the warm stuff you push out of the house.

The Mistubishi losnay looks to be a much better idea, and it is actually recovering the heat from the air you remove. Not heard of anyone getting a quote on it, but with the rip that HRV charge I cant see it being much more then that...

Link to comment
Share on other sites

Their advertising is pretty clear that you will get a warmer dryer home with the HRV - all mum got was a dryer house which needed more heating then before. I had no idea that they were charging that much for a heat recovery jobbie, they are pretty much the norm in the UK and noway near that expensive.

Link to comment
Share on other sites

Their advertising is pretty clear that you will get a warmer dryer home with the HRV - all mum got was a dryer house which needed more heating then before. I had no idea that they were charging that much for a heat recovery jobbie, they are pretty much the norm in the UK and noway near that expensive.

Yeah, can't imagine why a heat exchanger would cost much, it's just a bit of ducting and some thin dividers. I could make one up with some tubing, plastic sheeting and MDF.:P

Link to comment
Share on other sites

Hi everyone,

We bought a house 2 1/2 years ago and when winter hit we had major problems with condensation, mold, dust mites, and our fish room was on new carpet so we had to run a dehumidifier in the room to dry out any spills. The 2000+ litres of water which included a 400L open topped tank was a big contributor.

After the system was installed the lessened condensation was immediately noticed and after a few days we no longer had weeping windows. The mold was cleaned and didn't return and pretty soon I noticed that spills dried out of the carpet without the dehumidifier running.... the dehumidifier was costing about $75 a month in electricity so this was a welcome discovery.

The only downside to the HRV system was that the leaves from the sword plants growing out of the planted tank soon died. 100% sure that this was due to the air becoming too dry but with all the pros this was a con that I was happy to live with.

Not sure if they still give a 2 winter guarantee but we're about due on ours and we're keeping it.

Thanks Bilbo and HRV.

Link to comment
Share on other sites

  • 1 month later...

FYI my husband has been doing mega research and we are no longer having HRV installed and instead having Intellivent (like Mitzubishi's Lossnay) installed which is a few hundred dollars more but he assures me it will be better and has tried to explain it to me by drawing pictures which look like houses with a uterus and fallopian tubes in the attic.

I report back once it is in.

Link to comment
Share on other sites

has tried to explain it to me by drawing pictures which look like houses with a uterus and fallopian tubes in the attic.

I report back once it is in.

Sounds interesting.

The lossnay system seems quite good as it use the already warm air insde to heat the fresh air vented in.

my DVS is making quite a draft at the mo as i can see the peacock feathers we have in a vase moving around and there is no other movement in the room. Its suposed to cut out when the temp drops, but i think mine is either wired up wrong or faulty as it seems to go nonstop.

Just my two cents

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...