Can't give you a rule of thumb that works across the board in *all* cases.
D12 is a district that covers some of the most expensive areas on the southwest side of the city (aka Broadmoor). It has some more affordable homes but some very pricey ones too, just depends on which part of D12 you're looking at.
D20 is the northern suburbs. Most of the homes are more consistent in size and cost, very few super custom homes with high prices. Lots of homes up here under $300k. D20 schools are considered among the best here, primarily along with D12 and D38.
See representative home styles/prices on realtor.com, using zip codes as found in this old thread:
-
http://www.city-data.com/forum/color...springs-s.html
s/Mike