We have had a HRV installed for about four months so I was very interested to see if it was a good idea. the main benefits have been the ventilation - the air is obviously fresher, The system attempts to maintain the temp at the twenty degrees I have set it to, and it doesnt cost as much to run as air conditioning would. Re the earlier comment re not beig able to turn it off 'cause it comes back on, that is an option I discussed with the installer and he turned that feature off so I can turn it off permanently if I want to. If you ring them they will guide you through it. So far i am happy with it though I feel it is costly for what you get.
Skolink: In terms of heat recovery, HRV has been scientifically proven to be a waste of money (Otago University). As already mentioned there are much less expensive options for bringing in outdoor air and filtering it, like the Securimax 'heatrans' kit with a 'summer kit' and filter added.
do you know of any installers in dunedin who offer the apparently cheaper alternatives?
my main issue is heat transfer - in dunedin you need every bit of help you can to heat a house.
yes, insulation is the first thing we will look at, of course, and then think about the cheapest fire burner type ... but you can't get the heat around the house unless you have a heat transfer system that's good ...
sonyxperiageek: Could you please tell me your experiences with HRV? Especially those people who have allergies and do they minimise the effect in the air? My house is very hot these days especially in summer so I guess it should do well with cooling the house abit with the near-cold air it forces into your house.
Our Landlord installed a "smartvent" system early last year. I have always been sceptical about these sort of systems, but NO more. I am now a firm believer. Our moud and condesation problems ceased within a few days, our kids ashma is no where as bad as it was, the house is dryer and easier to heat in winter. The system (apparently a NZ one) can have extra kits added like "summer mode" to draw cooler outside air in during the summer and heat transfer option etc. In the winter, you can actually feel the heat being pumped in from the roof space. It is awesome. They do work but don't expect it to act as a heater on it's own though, even though you can get heater options. Well worth the money and if you are a handyman you can install it yourself. I think most electircal wholesalers stock them. Can't speak for HRV though. No expereince of them although we did have a quote and though they were overpriced to hell.
I would never want to live in an older house (pre 60's) again without one..
Just some observations from my experience doing just this:
The ducting has close to no thermal insulation at all. The longer the ducting is the more heat is lost through the ducting into the roof space. - So ideally, wrap the crap out of the ducting with insulation and keep tubing runs as short as possible.
The best you should be hoping for is to take the edge off the room that hasn't been heated directly. These systems work best when you have one room with too much heat, ie a log fire. If it's a basic gas fire/air con unit then you'll typically just end up cooling both rooms.
The air flowing into the new room needs to go somewhere, so you need to have the door ajar/vents in the door, which will then flow down the hallway and back into the lounge. If you block up either room, to prevent drafts etc then you don't actually get much flow.
We got an HRV installed last November. So far so good. Not cheap.
The sales guys are ruthless and put on the hard sell. Like Vampires don't invite one in until you have done your research are committed to an HRV solution. And then talk them down in price the best you can.
I found the installers to be somewhat rough-and-ready also so make sure you monitor their workmaship or you will wind up with corners being cut especially if they have a number of installs to get through on the same day as yours. They use the old eye-o-meter when cutting the holes in your ceiling. After sticking my head up into the roof saw they didn't mount the unit in the apex of the roof space but conveniently by the entrance to the roof space but no biggie as the pitch on the roof is low.
Ours is set to 21 deg in summer mode and it fires up between 9-10pm cooling things down in the evening as the roof cools (iron). Our roof space has been up to 45 deg over Nov-Dec and we haven't even had any really decent weather yet!
We didn't notice the 'fresh air' factor after it went in which was good. And it has barely made a dent on the power bill.
It was pitched to us that you should address ventilation first then insulation and finally heating as once your ventilation and insulation is sorted as it is far more efficient and cost effective to keep it heated. Chuck a heat pump in a poorly ventilated / insulated home your heat pump will be working hard and your power bill will be through the roof... along with the heat it is producing.
Ventilation systems such as HRV don't qualify for the Government's EECA (up to $1300) grant which is a shame but to be expected.
HRV won't heat your home, if you want heat get a heater. But it will get rid of damp and make the home easier to heat.
pryannz: It was pitched to us that you should address ventilation first then insulation and finally heating as once your ventilation and insulation is sorted as it is far more efficient and cost effective to keep it heated.
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HRV won't heat your home, if you want heat get a heater. But it will get rid of damp and make the home easier to heat.
It's true that air with a lot of water in it will take a lot more energy to heat than dryer/fresher air. However if you're heating air and then blowing it out of your house and replacing it with cold air from outside, then I think you need to be careful about those sorts of statements.
It's a triangle of heating, ventilation and insulation, and from a financial point of view you can't have all 3 without it costing you. Like the say, if you take the V out of HVAC you just get a HAC job.
It's all about balance, and as has been said before, with damp issues you might want to do a bit of investigating work to determine where the water is coming from in the first place, rather than just blowing the water away.
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