Just installed a new electric hot water heater. The tank is getting hot but the water in the house is luke warm. Please help!

Hi Bethaney and Welcome to The Plumbing Page. At AskMeHelpDesk.com. You're responding to a 3 year old dead thread so I gave you one of your own. Look in then upper left hand corner of the first post form the date before you post, Thanks,
Several things come to mind.
Is the pip[e on the hot water side hot to then touch?
Are "heat trap nipples" (see image) installed?
Is it possible that you have a cross connection in one of your single handle faucets? What have you done so far to check? Back to you, Tom

Also... in addition to Tom's advice: make sure your both elements are set to 120 F. Usually, they come factory pre-set to lower setting. Back to you. Milo

Did you completely fill the new heater before turning the power on to it? Do you have a recirc line. Do you get hot water in any fixtures, or not anywhere in the home? Let us know exactly how you made the new connections to the water heater (sweat/solder) etc. Lots of option here. Please give as much info as possible and we will do our best to help. Lee.

There is 110 going to each element on the hot water heater. I don't think any lines are crossed because the one that I had taken out was getting hot but was old and rusty and was only staying hot long enough to take a short shower. It's a 50 gallon Whirlpool that I bought. I filled the tank then got all the air out of the lines in each faucet before I turned on the breaker. I opened the drain valve on the bottom of the tank to see if the water is getting hot in the tank and it is. When I turn on the water on the cold side it is ice cold and on the hot side it is cold then a bit of warm then cold then luke warm.

It looks like your heating element(s) are damaged.
Try this: Raise the temperature to 125 on each element. See what it does.
Back to you. Milo

I've changed both of them out to eliminate that issue just in case. Could it be the tank itself? I've been told that those are not good water heaters (of course after I bought it)

Tank is only a holding tank. The problem is most likely electrical. Did you check the fuse / circuit breaker to make sure it is not tripped ? Back to you. Milo

it is cold then a bit of warm then cold then luke warm.

That sounds like a dip tube problem. Answer MGD questions about how the plumbing was done. Did you do any soldering close to the cold water input connection?