"using a saddle valve"

Do not use a saddle valve.
They are a cheap attempt to reduce installation labor that do not seal very well.

They clamp onto a pipe (the saddle part) and then either pierce the pipe or a hole is drilled into the pipe for the water.
The biggest weakness is they do not shut off very well (no seal from the stem to the pipe hole) and rely completely on a rubber washer between the valve body and the pipe to seal the valve to the pipe.

Never like to discourage conscientious DIYer's, but.....

Leaks under the sink (where they typically go undiscovered for a while) can result in a lot of damage in a short time. The connection principals are simple enough to understand but leak-causing errors in pressurized lines can be hideously expensive.

Since you say you "have no idea", I'm suggesting caution for you. Even though the lines are small and the concepts are simple, the thing really must be done absolutely right. If you're confident in your ability along these lines, by all means proceed. Just suggesting not getting in over your head.

In decades past, I've paid plenty for doing things wrong myself.

gb85-
Based on your lack of experience, I think there are many opportunities for you to screw this up. I, too, hate to discourage a do-it-yourselfer, but I don't think this is the best plumbing project for someone at your basic level. I'm going to suggest you have a plumber do this.

gb85,

Most, if not all, horror stories you found in your research were posted by people who didn't know what they were doing and proved it.

For reference...

SADDLE VALVE = BAD

PE (polyethylene) TUBING = NO PROBLEM

Any appliance that can use PE tubing can use copper tubing but will/may require different fittings.

All one needs to do anything is the knowledge and the tools. Lacking either and considering the expensive damage a mistake can bring you should consider a plumber and think of the cost as tuition.

That said, what don't you like about your water? Are you on a well or water system? what are you wanting to filter for? Additional faucet at the kitchen sink or ice maker/water dispenser in the fridge also? Is your water softened?

Thanks for all the responses. I didn't realize until I read the responses and reread my post that it reads as if I am going to DIY - no worries - I wouldn't touch this one. What I should have said was that I was going to HAVE one installed and I was trying to educate myself. Everyone did confirm the saddle valve = bad and the tubing is OK. That is what I needed to know so that I could be more knowledgeable when talking to the plumber.

thanks!

When you go shopping for a filter... look for a brand name not an anonymous pacific rim model. You'll want one that uses standard, easy to get, replacement filter elements. It should also have an air-gap faucet.

Tell the plumber you'll want it "T"ed in with a small shut-off valve for filter changes not "saddle-clamped".

And I'll ask again... what don't you like about your water? Are you on a well or water system? what are you wanting to filter for? Additional faucet at the kitchen sink or ice maker/water dispenser in the fridge also? Is your water softened?

I'm going to plug Aquasanna here. I have had one for years and 1 problem that I had they sent a whole new unit..This is a high quality filter but it is NOT a RO filter. It removes the contaminents but not the minerals. One nice thing is that with the optional sink mounted spigot, the only time there is pressure on the system is when you turn the spigot on. However, for this reason you cannot plumb it into refrigerator ice makers.