Video: How to Choose the Best Plants for Your Landscape
One of the more difficult issues facing you will be making sure you compare apples 'n apples while understanding the differences between apples 'n oranges.
Some things common to all:
How far from your (water) meter pit to the home?
Do you know what sort of water pressure you have?
Those two questions sortta drive the rest. How many sprinklers you have is a piece of the puzzle but it is lower on the issues list than how much water pressure and gallons per minute of flow (gpm) you have. Knowing the water pressure and gpm coming to the house is important because it is the info divided by the flow rate of the heads to tell you how many you can run at a time.
That, plus the number of heads it takes to cover your yard will let them decide on how many zones to cut the yard into (each zone is X number of heads that run at the same time).
Will the different estimates be for systems that are all parts from a single manufaturer or will it be a collection of brands? Some will tell you that the parts (controller, back-flow, heads and even specific heads) are better from different manufacturers while others will tell you that all from a single manufacturer will give you an optimized system.
And, are the contractors equally certified? Not only education and experience but certifications from the various manufacturers who's parts they want to use. And, will their installations be the same? Will they open trenches all around your yard and be a week getting the stuff layed, connected and back-filled? Or, will they pull the flexible pipe and be in 'n out in one day with water flowing to cover their intrussion before they leave that day?
Will your system need to be blown out with pressurized air at the end of the season to avoid winter freeze and bursts or will it drain automagically?
I know, I took your simple question and made it hard.
When I bought my system about 9 years ago, I had a variety of estimates and the differences sortta fell into the mess I listed above. The low estimate was a person who seemed to be from the "get it in the ground and fix it later" school.
The highest estimate was from someone who seemed more concerned about my yard and the final result than I was. The low person was using parts 'n pieces from a variety of manufacturers. The high person was certified by the company that made all the parts he was wanting to use and he carried a fairly high rating from them for his past performance.. He would vary for me if I wanted but he had sound reasons from the controller to each of the heads as to why he preferred his "brand".
It doesn't look like you are a member of Angie's List. Given the size of the investment you are looking at, this might be a great time to join and see how others in your community have rated the contractors you are considering or if there is one you should add to your list.
My yard is between 12 and 15,000 square feet less the house, deck, two mini-barns and it is interrupted with a number of blocking (blocks the stream of water) evergreens and planting beds.
The low estimate I had was about $2,500 and would take three days to put in from the time they began to trench. I don't recall how many heads he wanted to put in but if it was off, he'd be able to put another anyplace and tie it to the nearest zone to give me good coverage. Uh, this was the get it in the ground 'n adjust later person.
The high estimate I had was around $4,500. This proposal was for seven active zones each having 5 to 7 heads. There was enough capacity (extra zone controllers and space within the system controller) built in to add drip irrigation at a later date for the planting beds without having to replace anything. He drew the entire yard and gave me a copy with the heads marked showing the "throw" of each and the overlap he built in to avoid any missed areas. And, they wanted to arrive in the morning and leave that evening with the system watering to cover their tracks throughout the yard. One day and they would not leave until it was working as advertised!
I took the high estimate. I have a neighbor who bought from the other folks. Both of us are happy. He is really happy because each time he calls his company for adjustments or corrections (yep, they got it in the ground and are still putzing with it) they are out within the week, they are really easy to do business with and their service calls' costs haven't gone up a whole bunch.
Sorry, you can't look at the price and divide by X number of heads and have a fair comparison.
1) IF you are talking the root crown - the portion where it is not one solid truck or "bole", but still a solid or near-solid mass of roots coming off the base of the trunk, then that has to come out on way or another. Typically, once you get beyond about a 3 foot circle then you are in the radial portion of the roots where they spread out laterally, and are a foot or more apart, and new roots can grow in that area fro the new tree OK. Of course, be prepared to have to trim some volunteers so the old tree can't come back, and be sure to fertilize the new tree per recommendations because the old roots will still be trying to extract water and food from the soil to support the tree that they do not yet realize is gone. Do NOT put stump killer or poison in the old tree - will kill new one too.
2) The proper commercial way to do this is to have the entire root crown and larger roots removed with a stump grinder - looks like this -
You need a tree service that can grind down at least two feet below ground level and remove the root crown and larger root segments. If you hve large roots running laterally quite a ways, he can grind them up too - ditto to "trippers" sticking up above ground. Just be sure to have it clear (spray painted) upfront how far he is going for what he quoted - typically about $150 for tree up to 1-2 feet in diameter, up to $500 for a massive sycamore or walnut or cottonwood or redwood with 6 foot diameter crown. While you can rent stump grinders at tooll rental places, I REALLY do not recommend it - the rental ones you can afford to rent for one use are pretty light duty, and they can chew a person up in no time flat if you lose control when it snags in the wood or hits a rock.
3) Another way is to go out to where the massive roots taper off to something you can reasonable cut - say 4-6 inches in diameter, and cut them all in a circle around the stump, then with a come-along or CAREFULLY (not more than a few hundred pounds) with a vehicle with a trailer hitch, put a steady pull on a good rope or strap or chain in a shallow notch cut around the top of the stump (so it does not pop off easy), then while it is being rotated up out of the ground walk around and cut any root you see still attached or trying to lift out of the ground. This works much better if the stump is left about 4-6 feet high so you get some real leverage on it with the pull, but if already cut down short run chain or strap over the top of it and around a large root on the far side of the stump. I use a Sawzall with foot long coarse tooth wood cutting blade for this - goes through roots really fast, and blade is only $1 or so apiece so ruining one or two hitting rocks is no big thing, and also reaches in under the stump better and safer than an axe. I helped a neighbor take out a back yard full of birches this way - took us about half a day to remove about 15 trees with about 6 foot diameter circle of crown and roots, leaving holes about 1-2 feet deep where each tree was. Remember this - whichever way you use to take it out, you will need maybe 1-5 wheelbarrow loads of good growth medium to replace the divot.
4) Cheaper route - cut off flush with ground level (or leave some stickup as a planter or stool or feeder base or whatever), and plant new tree at least 4 feet away from old crown, in a spot between the old roots.