I have had 2 separate HVAC contractors come to my house to pre-inspect for installing an HRV. Both said that it wasn't doable due to the 'grade' or how close to grade my basement was (or windows). I must not be the only home with a low basement, which leads me to believe there must also be a solution for to my home not meeting the standard requirements.
it may be possible if they go thru the wall then dig into the ground and then gooseneck the pipes up above grade and the average snow fall level. if not high enough it will suck in snow and feeezeup. not a pretty looking setup but it is possible with extra work and cost. google Lifebreath HRV and check their site as you may be able to look at their install info
"Cut it twice and it is still too short".