Does anyone have an opinion on the brand for one of these units?

Yes! UltimateAir's RecoupAerator is the most efficient means of bringing outside energy indoors in terms of energy savings and cost. It is a whole-house ventilation system that removes contaminants from inside the home, and utilizes a MERV 12 rated filter that captures outside air pollens and mold spores, ensuring only fresh air is released into the home.

As a ‘green’ product, the RecoupAerator® also possesses a 95% heat recovery rate -the highest rating in the industry - coupled with the lowest electrical footprint and the lowest cost-of-ownership.

For more information check out http://www.ultimateair.com

I just took delivery of a RecoupAerator for installation and (sorry so slow), but in a few months time I will be happy to post a review of installation and performance.

Treetops - what is cold climate for you? Everyones perspective is different. If you are in truly cold climate (north of the 49th) you need to look at how the unit deals with icing up in winter. Does it just shut down and turn on electric elements? How much time will it be in defrost mode when it is -20c and you indoor humidity is high?

I am interested to know, what brands did you already have in mind?

Furnace Repair Seattle

There is a discussion at: http://www.greenbuildingadvisor.com/community/forum/mechanicals/14674/most-energy-efficient-erv

I have a Venmar Eko 1.5 HRV that cost around $2000 professionally installed.  My calculations show that it likely will not pay for itself in my dry, heating-only 7000 heating-degree-day climate, as the payback is over 10 years and the motors will probably not last that long.  I think most ERV's have more moving parts than HRV's, so likely higher maintenance.  If you pay significantly more than the $2000, I would do the calculations to see if it has any chance of paying for itself.  The Venmar unit has worked fine, is quiet, and can be run in "recirculate only" mode which I like when I want to even out temps from the passive solar.  The HRV does tend to dry the air, a problem in this very dry climate (Colorado mountains).

The "payback" on HRV isn't necessarily in utility savings, but it allows you to run fairly high ventilation rates without a big energy penalty. If you stick to the ASHRAE per-person minimums (and only while the space is occupied) you can go with lower ventilation rates, with much lower drying factor in winter.

Some people put them under dehumidistat control in winter to limit the drying capacity. This is usually fine, so long as you don't have significant indoor air pollution hazards, and rigorously use exhaust venting to purge cooking/bathroom air contaminants.