Anyone know about HRV systems?

Has anyone got one? We have been looking at getting one and the info does sound good. Our house is single storey and long so we'd need 6 outlets from the ceiling. Even the cost seems reasonable so are there any downsides and what are they?

We have the DVS and it is great, no more mucky windows, keeps the house dry and helps warm as well. I love it.

I have just installed a ventilation system in our long house. Most of the parts were obtained via Trademe, or from the local electrical wholesaler.

Intake vent close to the fire, inline fan, long 200mm ducting down the length of the house in the ceiling space. Tee-off in 150mm to seven ceiling vents along the way. Fan turns on when the temperature in the lounge reaches (adjustable) 17deg.

I don't think it cost me more than $300 in parts.

Can't really compare to a commercial one, they seem to have trendy control panels that you set once and don't touch again. Keep it simple.

i have 2 hrv`s because of the size of the house . I would not be without them, just majic
tkf

We have one and it rocks. On the sunny days we'd been having after frosts, it was heating the whole house to 20 deg during the day. On days like this it doesn't heat, but it keeps the house so dry that once you light the fire the house warms up much quicker. Well worth it, we'd put one in any house we owned.

Downsides: The cooling doesn't work that well in summer, takes so long for the roof air to cool down, but is better than nothing. It circulates air all the time, so if it's very cold in your roof, that is the air that is coming into the house. On the very cold nights I have just switched it off before going to bed, and it turns itself back on in 8 hours. Apparently they now have a heating add on that wasn't available when we got ours installed, I'd go for that if you can afford it.

Oh, and the filter when it was changed after two years was vile. Full of what looked like road dust (we live on a gravel road) - but the HRV guy said ours was the cleanest he'd ever seen!

I've heard a few people talking about them and they have all said they were a waste of time and money!!!! No change to the temperature in the house and no change to the heat needed to warm the house!!

Having said that, I am looking at putting in a new wood burner and will also put in a ducting system from the room with the burner to the rest of the house. This takes the heat from the wood burner room and spreads it around the house - much more sensible than using roof space heat.

www.bdt.co.nz/lossnay/systems.aspx

have a look here , if hrv pulls warm dry air from the attic then does that mean it fills the attic with damp cold air from out side , have we yet seen the full effects of hrv systems on our houses structure?

HRV means heat recovery ventilator.
DVS just sucks cold stale dirty air from the roofspace through a filter into the house through 1 inlet ,for it to be effective in the entire house all the doors have to be open as well as the curtains this is what the hrv man told us (imagine trying to heat the house with all doors and windows open). HRV is the same system but with an outlet in each room thereby eliminating the leaving open of doors etc ,this is also what the hrv man told us when we had him around to quote he thought it was a good system and maybe it is but it is not a heat recovery ventilator more like a transfer kit .Either way both systems are not heat recovery ventilators. A true hrv draws fresh clean air from outside the house at an appropriate point it is then passed through a heat exchanger and gets ever so slightly warmed up by stale warm moist air drawn from inside the house ie bathroom ,kitchen etc, this moist stale air once through the heat exchanger is cooled and gets expelled to the outside ,with the new clean slightly warm fresh air pumped into the remaining rooms in the house which ever rooms have ducting. "HRV" have an add running on tv now via Mark Ellis claimimg to draw the warm air from the roof space into the house making it warmer ,well what a load of crap that is my roof space during the winter is freezing cold and i certainly wouldnt want that freezing air pumped into my house while i was trying to warm it up and viceversa during summer my roof space is like an oven with air so hot it is difficult to breathe up there, once again not the sort of air i want pumped around my house during the summer. Google "clearaire" a company in Christchurch who have been making HRV s for about 25 years and i beleive lossnay have the same or similar system but havent been to their website yet .It is definately true a dry house is much easier to heat than a damp house and even a couple of degrees make it a lot easier to heat up . The Clearaire system replaces all the air in the house about 3 times daily, there are downsides though, if you have downlights which are ventilated you have to change them as these make installing a heat recovery system a waste of time as they make the system ineffective by allowing air from every room with the lights on to get drawn into the roof space and force cold air in the roof space into the rooms with the lights off, sounds complicated I know but look at the website for clearaire and it is explained a lot better. We dont have 1 yet due to cost and the fact we have ventilated downlights which would need replacing first for the system to work.
Hope to one day get one in the meantime we just crank up the contessa woodburner and cook . Might in the interim just install a heat transfer kit or make my own as wyseyes has done.

Yep just went to the Lossnay site could have saved myself a lot of typing if i had gone there first

there was a HRV system already fitted when we moved in and I thought 'great, that will keep us toasty in winter"....wrong.
it moves air down from the loft space and thats fine if the sun has been warming the roof - in late spring or early autumn, but its just rubbish in winter.
I keep it on during the day because it does help keep the condensation down but it gets turned off on a night.
If the inlet had been put above the woodburner that would have made much more sense...... and I did look into the add on heating systems they can supply...v v expensive. oddly one of them was a heater for your loft space but it only raised temp by 5 degrees and surely most of that would be dissipating out of roof???
dont think I could recommend one in all honesty based on experience.

We had a DVS at our last place and it was brilliant. The air was sucked in from outside, not from in the roof space. But I doubt any of those systems could act as a heater unless they have a heater unit in the roof, as beaker says, through which the air is passed.

We did find we had to heat in winter a bit more, but that was fine as it did get rid of the dampness - before the DVS we had windows literally running with condensation, post-DVS installation that problem disappeared. Our biggest problem was unflued gas heaters...

There is a winter setting on these things. Not sure how it works, but it does.

Toni - Northland;263715 wrote: There is a winter setting on these things. Not sure how it works, but it does.

it might have a heater bank in it , turn it on and see if your meter goes from 3 rpm up to 6 trillion rpm [}]

PT ...............sorta

Probably if you live in the freezing cold south it mightn't be so good, but in the more temperate north where humidity tends to be high it is great. And it uses virtually no power that we could discern, similar to an electric fence I'm told....

hrv, excellent.
cold damp house became so cosy!

when sun heats up under roof it drags down the warmth to the house.
when warm nights drag down the cold air.
no added heater but house is so much cosy!
I can dry wash indoor over night!!!!
When heating up the house it goes faster to heat up and so much more pleasant warmth.