Is it possible for new insulation to make my house hotter?

If you can't see your rafters and the material is shoved against the roof deck, your soffits are almost certainly buried. Those crews are often paid by the bag or the job, so they "blow and go" without a second thought for ventilation. When the intake at the eaves is blocked, your ridge vent or gable vents become useless because there's no cross-breeze to push the hot air out. That's why your AC is struggling; you've basically turned your attic into a pressurized heat box.

There is one way to check from the ground without digging thru the fluff. Grab a **leaf blower** and head outside. Stand under your eaves and blast air directly into the soffit vents for a few seconds at each spot. If the insulation was just loosely piled over the holes, the force of the air might push it back enough to break the seal. If you have a helper in the attic—make sure they wear a mask—they can tell you if they see the insulation shifting or "dancing" when you hit it from the outside.

Another trick is the daylight test. Head up into the attic on a bright, sunny day and turn off every single light, including your flashlight. You should see a faint glow or slivers of light coming from the perimeter where the roof meets the floor. If it's pitch black all the way to the edges, those guys definitely packed it tight. It’s a common mistake with crews who aren't used to residential venting requirements and just want to get to the next site.

You're likely going to need to get **proper baffles** installed to fix this permanently. You can't just move the insulation back because it'll eventually slide or blow back over the vents again. You need those plastic or foam channels stapled to the roof rafters to create a dedicated air path. Also, if they only added 3 or 4 inches, they didn't get you anywhere near R-38. You'd usually need about 12 to 15 inches of total depth for that. It sounds like they shorted you on material and killed your airflow at the same time.

Have you ruled out a coincidence with the AC unit itself? It’s easy to blame the insulation because it’s the new variable, but have you checked if your capacitor is failing or if the coils are just dirty? Also, if they were rushing that fast, have you ruled out them knocking a duct loose? If a return line got disconnected, you're sucking hot attic air into your system. A few blocked soffits usually take a while to bake a house, but a busted duct will kill your efficiency instantly. Might be worth a peek at the HVAC runs before you start digging in the eaves.

You definitely need to get some airflow back or your roof deck is going to bake. When you go to fix this, grab a stack of Owens Corning Raft-R-Mate baffles. I’ve tried the cheap generic foam ones and they just collapse under the weight of heavy blown-in stuff. These OC ones are way more rigid and have a built-in air channel that actually stays open. You’ll have to pull that insulation back from the edges, staple the Raft-R-Mates to the rafters, and then push the fill back against the bottom of the baffle. It’s a sweaty job, but it’s the only way to get your AC back to normal.

Spot on about those baffles. One thing people usally overlook while they're up there wrestling with the insulation is the 'wind washing' effect. If you don't secure the bottom of those baffles properly against the top plate, the fresh air coming in from the soffits will just blow your new loose-fill right off the edges of your ceiling. You'll end up with major temperture swings right along your exterior walls becasue the insulation gets pushed back a foot or two. I used a long garden rake to pull the fluff back from the eaves—saved my back from having to crawl into those tight corners.

You're basicly living in a Crock-Pot right now. If that’s cellulose—likely GreenFiber—it’s dense and heavy. If they just "mountain peaked" it without baffles, you've got zero intake. I’d grab a Klein Tools IR5 and hit your upstairs ceiling. If you’re seeing 90+ degrees on the drywall when the thermostat is at 72, your attic is a furnace.

Pull that stuff back at least 6 inches from the eaves immediatly. Also, verify your settled depth; for R-38, you need exactly 13.75 inches of ProPink L77 or about 10.5 inches of GreenFiber. If it's shallower than that, those guys short-changed you on the bag count on top of killing your airflow.

Update: I checked the AC and the ducts seem okay, so it’s definately the insulation. I poked a broom handle near the eaves and couldn't feel any air at all. I’m going to grab those Owens Corning baffles someone mentioned. One quick thing though—if I pull the insulation back to install them, how do I make sure I’m hitting that top plate to prevent the wind washing you guys warned about?