Well we ripped out our electrostatic air filters which needed cleaning every three months and put in paper filters. I feel bad about using more paper, but they just plane work better. So I guess I take the recommendation. These filters are really confusing to buy but there are basically two parameters:

• Size. There is much written about Honeywell approved or whatever, but it seems that the main thing is to get the correct dimensions and do a little shoving. In our case, we have some screws that are there so it doesn't quite fit 20x25x5, but the thing is just paper anyway.
• MERV. This stands for Minimum efficiency rating value and basically is how efficient the filter is. The grades are 9-12 for higher end home, 13-16 is medical grade and 17+ for pharmaceutical clean rooms

These things only last a nominal six months, so pricing does matter, but it is interesting to see how the curve really goes. From Amazon in looking at this the off brand MERV 12 seems like the best price/performance.

• Nordic MERV-12 ($41/2) for a box of 2 from an off-brand Nordic MERV-12. So that is just • Honeywell MERV-12 ($32 or $104/4) so there is a 20% premium for name brand if you get four of them. • Lennox MERV-16 ($89). Well this is the top rated by Consumer Reports and it is medical grade, so something to get if you are really allergic. That's a pretty amazing filter.
• Nordic MERV-8 ($32/2). So if you go low end then it is still$16 a filter, doesn't seem really worth it when you can get a MERV-12 for $20 off brand or$25 from the OEM.