My power bill was $333… my friend’s with a bigger house was $160. Wtf am I doing wrong?

Our house is about 2500 sq ft in cottonwood heights. We just got new insulation, but the insulation is blocking our deck vents in the roof. There are no soffit vents. We have a top ridge vent. Could this be why our bill is so high?

We’ve been keeping the house at 70. Is that unreasonable? We don’t have a smart thermostat.

Also my friend said closing the basement vents in the summer is recommended since the basement is already cool. Is that correct?

Our windows seem fairly new (probs 15 years old?), so I hope that’s not it.

I feel like a big ding dong that doesn’t know what she’s doing when it comes to house stuff🤦🏻‍♀️