I have been reading this forum for quite sometime and find it very educational and interesting.  About 3 years ago I helped my brother install a 5 ton unit with a closed horizontal ground loop.  We are in central Maine and at the time didn't know anyone else in the area that had done a geothermal system so he basically researched it and we installed it.  I've seen DIY stories on here that aren't favorable, but a long story short, the system works really well and he's extremely satisfied with its performance.  Now I'm going to install one at my home.

My biggest concern at the moment is my ground loop.  We used four foot wide trenches about 7 feet deep with his ground loop (5 trenches about 250 feet long) and placed the 3/4" pipes on the outside edge of the trench.  It worked out well because our father had a large excavator with a four foot wide bucket and his house is located in a large field.  Now at my house, my ground loop will need to traverse through the woods.  I was wondering if anyone would have any input on using a trench about a 1.5 foot wide instead of the 4 foot wide like we used on my brothers.  The purposes being, our large excavator is just too large to fit through the woods without clear cutting the entire area and a smaller one would be easier to sneak through the woods.  I considered a vertical closed loop, but the horizontal would be much cheaper for me since we have the epuipment to use.  I am planning on a 5 ton unit and was considering using the same idea that we used on my brothers for the ground loop, 5 trenches 250 feet long, but only 1.5 feet wide, but worried about the efficiency of it.  Do you think that having the pipes 1.5 feet a part rather than 4 feet will make a huge difference?

Does anyone have any thoughts or suggestions?

Thanks.