This is from partially the file data/Balance/PlacementData.cml
Hovels are greek_abode_a. They cost 280 wood to build. Each hovel boosts the total capacity of all housing within a radius of 20 by +3 people each. Having multiple hovels together together can through overlapping capacity bonuses add a max of 11 additional people. This raises the base capacity of housing 5 adults and 2 children to housing 12 adults and 6 children. They also have a -0.9 to -0.2 happiness for the same radius, and add 0.1 productivity to all fields and refineries within range.
Note Japanese hovels have a much larger footprint than the greek version, and while they radiate out the capacity bonus to greek buildings nearby, they themselves have a max capacity bonus of 0. They really aren't worth bothering with, the greek hovels are so much more superior at what they do.
Houses cost 300 wood to build. They have a larger range, 22, but add only +2 people capacity bonus to all nearby housing buildings. They are -0.4 to -0.2 happiness, and add the same 0.1 productivity bonus to all fields and refineries within range. Here again there are limit caps to the capacity bonus that make the greek version of the house superior to the japanese version. The greek house has a capacity max of +4, which raises it from housing 7 adults and 3 children to 10 adults and 4 children, and a much smaller footprint. The japanese house shelters 5 with a max cap bonus of +3 for a total of 8.
Villas cost 320 wood. They are have a 22 range, and also have a +2 capacity bonus to all nearby housing buildings. They have a tricky happyiness range -0.2 for those near, and +0.2 for those at the edgeof its effect radius. This is why you tend to see some players spread out their villas, to get that +0.2 happiness bonus right at the edge of the radius range. As with all housing, they add 0.1 productivity to all fields and refineries within range also. If you choose to shove them as close together as you can, you can get the +2 capacity bonus to every other housing building within range. Unfortunately the max capacity bonus of a villa can receive is +1, meaning you go from 7 adults and 1 child to 8 adults and 1 child. Villas by themselves will bottleneck your number of children and so the number of adults you'll have later on. If you're going to have a lot of adult immigrants from the cities you've impressed entering, this is good. If you need to keep refreshing your army after casualities, villas will bottleneck your children population, which is bad. The 0.1 productivity bonus to fields and refineries is for the 22 radius as well.
Manors are greek_adobe_d. They cost 800 wood and 200 of the much more limited ore to build, and they have a slightly larger range of 25 radius. There is NO capacity bonus to other housing, ever, but in exchange they range from +0.2 to +0.4 happiness --so even if you build them close to other housing units they're still happy. The 0.1 productivity bonus to fields and refineries is for the 25 radius. Both manors and mansions do much better if mixed with their more lowly brethern that offer capacity bonuses. Manors built grouped by themselves are missing the important capacity bonuses offered by the smaller buildings. Manors have a maximum cap bonus of +2 which will boost them to housing 8 adults and 4 children. The japanese manor again has a much larger footprint than the greek version and is not worth bothering with since it maxes out with a +3 bonus at 5 adults and 3 children.
Mansions cost 1200 wood, 400 ore, and are greek_abode_e. There is no capacity bonus to other housing, but they do receive it from hovels, houses and villas nearby. They have an effect radius of 28, with happiness going from +0.2 to +0.9 at their far edge. The max capacity bonus they may accept is +7 and they at max are boosted to housing 8 adults and 6 children. The 0.1 productivity bonus to fields and refineries is for their 28 radius. Mansions should always have villas, houses or hovels nearby improving their capacity to maximize the return on the investment.
Skyscrapers cost 400 wood, 200 ore and have an area effect of only 20. They have no capacity bonus, and max out receive it at +2. This is a little but strange, since it only goes to children. A skyscraper on its own has 6 adults and 2 children per level. With the capacity bonus maxed out it instead housed 6 adults and 4 children per level ...which is not really helpful. Happiness ranges from -0.3 to -0.1. They also offer the 0.1 productivity bonus to field and refineries within a radius of 20.