Balance in house has been horrible since house was built....summer, cool in front hot in back(have to put window unit in every summer to cool bedroom)...winter, just the reverse....What's my approach?

Thanks

Several different options, but you'll really have to have an AC company come look at your setup to tell you what the best solution is.

If you built the house, you should have at least a 1-year warranty on this type of stuff and the builder's HVAC company will come adjust it for free. If you're past that point, you can replace the vent in the back bedroom with a hi-flow vent. That will make a big difference by itself.

Other option is to change where that duct comes off the big box on the end of the evap unit. Instead of coming off the side, they can move it to the end and it'll get better flow. Between those two, it should help quite a bit to at least get it livable, even if it's not the exact same temp as the rest of the house.

One more question: is the variation from the rest of the house larger in the summer or winter? Or about the same?

Just sounds like an air balance issue. Call and get pricing for a company to come do an air balance. Should only run $100-250. Or do it your self

Thanks ..
.patriot...bout the same...I'm hot in summer and cold in winter in back bedroom...
Jons... Thanks, that's what I'll probably do.....I'll see what they say....

No problem. One thing you can do yourself is go around vent to vent and feel which one is blowing the most. If it is a small room you can close the damper some and it will push air to the other areas. Air is like water in that it will take the path of least resistance. When you restrict the air in one area it pushes to others. One key thing to look at also is return air. Make sure you have return air in the hot/cold zones. This could be as simple as making sure the door to the room is open or cracked. With out a way for air to escape it will pressurize the room and will not allow for air change/flow. It will end up much like blowing air into a bag, with out it being open to allow the flow the air will stop moving in the areas.

Hows the insulation in the house? Last house I was in, my room had the same issue. We blew a good layer across the attic and it made a heck of a difference.
Also closed the other bedroom's vent a tad and it allowed more air flow to my bedroom.

I had a hot room on the west side while the MBR was cool. I ran an extra duct to the hot room by coming off the vbox that feeds the master. It worked quite well. If I do not need it then I close it.

Before we had a new HVAC system installed last year our master BR was always hotter than the rest of the house. They cut another vent in the room and problem solved.