Replies

1. 
   Clewless1 | Nov 19, 2008 04:58pm | #1

   If I'm reading the literature right, the venmar uses what I've always referred to as a 'heat wheel' style exhaust air heat recovery system. It uses a wheel w/ corrugated wrappings around a center pivot to allow air to move through. As the wheel turns to the other air stream, the heat it picks up is lost to the cold incoming air stream (as does some of the exhausted air).

   If you are trying to get rid of moisture, this approach doesn't work as well ... but still does work. Also some of the contaminants (e.g. odors) will end up back in the house (a no no in hospital applications). For houses the venmar will work fine. Haven't heard about icing damage ... fundamentally, not sure how the coil would be damaged. It tends to be fairly flexible ... nothing to damage. Not sure how it deals w/ ice ... as it would require a drain for when it thaws.

1. 
   anrl | Nov 20, 2008 12:42am | #2

   Thanks- are you saying that odors and contaminants would stay in the house in significant amounts? That would be a deal breaker right there. The contractor who recommended the ERV suggested it would be a big help in dealing with low humidity (which can be a problem here in winter) and that he has had no problems in the 15yrs he has installed them up here. He is perfectly willing to install an HRV (say, the Solo 2.0), but thought the ERV would provide better sevice.

1. 
   Clewless1 | Nov 20, 2008 05:33pm | #5

   significant? Not sure. If the contractor says it will be a BIG help w/ humidity ... then it would tend to be a big 'help' w/ odors ... as one generally follows the other. Personally, I don't think either would be significant ... but sometimes even a little odor can be 'significant' ... depending on your sensitivity to odors. I've not had experience with the 'crossover contamination' issue enough to render an opinion. BTW ... the HX coil should be removable and cleanable, I think. Make sure the contractor explains that to you.

1. 
   anrl | Nov 21, 2008 09:07am | #6

   Thanks much for all your comments and advice. I think I decided to go with the hrv, Venmar Solo 1.9, and contractor agrees that may be the best, especially since our house will be very tight. Sounds like we are right at the northern edge of where Venmar thinks these units are suitable. We only get an occaisional day or two of -40; they thought the Interior (e.g. Fairbanks) would not be a good idea, since it can stay down at -40 for weeks.
   Thanks, again.

2. 
   Tim | Nov 20, 2008 01:25am | #4

   " Also some of the contaminants (e.g. odors) will end up back in the house "

   This is a falshood, propogated by one manufacturer trying to take some market share from another, with similar but different transfer technology. Both of which I currently respresent. IN NO COMFORT VENTILATION application is there any measurable or significant transfer of exhausted contaminants (which is primarily CO2 and some nontoxic gaseous odors) to the fresh air stream. If one were foolish enough to utilze and ERU/ERV to exhaust and provide make up a laboratory hood with aggressive contaminants, there would be a concern.

2. 
   Tim | Nov 20, 2008 01:18am | #3

   I deal with these types of units almost daily.

   There are two types of "energy" transfer media to consider. A desicant based wheel or a "core". In comfort applications, like homes and offices, the energy recovery unit/ventilator is prefered over the heat recocovery ventilator. In applications like a natatorium or possibly a heavily occupied gymnasium, the HRV is the better choice.

   The reason being is that humidity (latent heat) is transfered as well as temperature(sensible heat). You want to recover the humidity in the house if possible. This will help to keep it from drying aout and requiring that you run the humidifier. The wheel type of ERU is the standard in the commercial industry, at least in the lower 48. It is well proven and is as durable as any other product on the market. It is possible to frost a wheel because it can tranfer too much moisture for the entring outside air (OA) conditions. There are several ways to combat frosting. One is a low limit thermostat that will not allow the unit to operate below a set temperature. Another way is preheating, usually with an electric resistence coil on the inlet of the unit. A third way is by slowing the wheel rotation or occasionally stopping and re-starting the wheel rotation (stop/jog control). In AK, I would recommend against a wheel ERV in a residential application.

   The "core" ERV, (some of the better units are made by RenewAire) is much less suscetible to freezing but still transfers some latent energy, but is less effective that the whell type, in most cases.

   I am familiar with Venmar products and they are very well made and highly regarded in the residential market. Honeywell does not make the unit they sell, and I do not know who does. It looks familiar, but I don't remember the manufacturer. Of the two, I would pick Venmar, but give Rwenewair a close look as well

3. 
   wane | Nov 21, 2008 05:08pm | #7

   okay, I have the opposite situation, too much humidity in the winter, so I've been watch'n this post closely ..

   you say your issue is "dry winter air"

   after comments by others your choice is a Solo???

   venmars site says this about the solo ...

   "A very popular choice and one of the best heat recovery air exchangers (HRV) of its category, Solo air exchangers deliver an exceptional level of indoor air quality and excess humidity control."

   one of us is missing something ..

1. 
   anrl | Nov 21, 2008 11:09pm | #10

   Yeah, it has been hard to figure out which way to go. Basically, it sounds like we are at the northern edge for where the ERV is considered advisable, and since the house will be tighter than our contractor is used to dealing with, he thought being sure that we could effectively deal with removing moisture (when needed) might be more important than the relatively small recovery of moisture we would get. If dryness is a problem we will deal with it separately with a humidifier. This is what they are doing in the Interior, where they have not found an ERV to be much help. Basically, I just feel more comfortable going with what we know has a proven record of working around here.

4. 
   cliffy | Nov 21, 2008 06:39pm | #8

   Although our climate is not quite as wintery as yours  (I just came in after shovelling the driveway for the first time this year) I will give my vote to the Venmar Duo.  I have one in our house that I built in 95 and it runs all winter circulating the air, switched only to ventilate when required.

   After all these winters I finally replaced the motor. It was under two hundred canadian and took about five minutes.  I have never had any problems with ice or frosting atc.

   Have a good day. Say hi to Fleshman and the retired nasa dude!

   Cliffy

5. 
   jjwalters | Nov 21, 2008 06:45pm | #9

   Hey hows it going up there? I lived up on Lazy Mountain for about four years. All we did was open the window a bit to clear the smoke out:)..............Great area of the country

   My Blog

1. 
   anrl | Nov 21, 2008 11:14pm | #11

   Well, that's right where we are building! On Clark-Wolverine, just before Wolverine splits off, overlooking the Matanuska.

1. 
   jjwalters | Nov 22, 2008 01:03am | #12

   113021.13 in reply to 113021.12 Take the road back into the canyon and up to the small bridge that goes over the Wolverine creek.Take a left down the dirt road following the creek, I lived there once in a huge barn. Then you go on up on the other side and you eventually come to the hippie village where they built houses in the trees and lived in teepees......stone city.I had friend there......a guy named Ryder owned the round house by the road......some others.Really a nice place to live in the late seventies/early eighties.My Blog