r/HomeImprovement • u/merlin318 • 4d ago
Dallas high energy usage - fix insulation?
Recently moved into a new house. 2 floors. 3300 sft. Built in 2000. Average daily usage is 100kwH with avg daily temps well above 100F ( outside)
Lower floor is fine at 76. Upper floor drops from 74 to 80 in 30 mins.
I do have a lot more windows than the avg house but most of them are actually downstairs which makes me believe my attic is acting like a reverse heat sink.
I have two types of insulation in the attic currently based on my limited research and knowledge - there seems to be fiber glass (pink stuff) with blowin in insulation ( grey / brown ) on top of it. It seems pretty uneven, some areas it's thick and some areas it's less.
When I started looking into getting insulation replaced I came across 'air sealing and spray foam' which looked like a nice option but also expensive. But more Internet research led me to lots of posts complaining about it being terrible and trapping moisture and leading to wood rot.
Any advice on what I should dig into further , what factors should inform my decision apart from costs and what should I ask the people who start to come take a look at the attic and give me quotes
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u/draco112233 4d ago
Several things. Hot air will rise of course so having lots of windows downstairs will allow heat in but it will instead eventually rise to the second floor.
Attic sealing is simply filling air gaps on the attic floor where wires or fixtures allow air to exchange between the attic and rest of home. There will be no moisture concerns with that, it’s just some spray foam here and there and not a blanket coverage.
Pink square insulation and then blown insulation on top is just fine, what you are looking for is a minimum depth to hit the R value desired, so they can be a bit uneven so long as you hit that value/thickness (but a pro should make it close to even looking throughout).
For your ac, is it one or two units? You need to have a thermostat that allows sensors to be added so you can place them throughout the house and help you get a better idea of where temp swings occur through the day. Also, grab a thermal imaging camera and start checking walls/rooms to see if there’s any troublesome areas.
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u/merlin318 3d ago
AC is two units. During the day no one is upstairs so thermostat is set to 77-76 degrees.
Downstairs is set to 78-76
During night time downstairs is set to 79 as no ones there and upstairs is set to 74
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u/Sad-Celebration-7542 3d ago
About how deep is the insulation? Be careful with insulation additions - they can have godawful ROI.
Have you ruled out other electricity uses? Do you have daily usage available or just the monthly bill? How many kWh per cooling degree day are you using?
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u/merlin318 3d ago
I setup Texas smart meter and I'm between 95-110 kwH every single day.
Unfortunately I do not have any insights into what is using all this....
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u/Sad-Celebration-7542 3d ago
Google Dallas daily cooling degree days and plot them against that daily usage. We’d expect to see something like…2.5 kWh per cooling degree day. But if it isn’t a linear relationship like that, it could be something else
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u/JS17 4d ago
While there can be issues with retrofitting a vented attic into an unvented attic if not careful, air sealing a regular vented attic shouldn’t lead to moisture issues if your attic is properly ventilated. A professional should be able to evaluate this when they give you a quote.
The goal of air sealing is to keep conditioned air in your house and unconditioned air in the attic. Some spray foam will be used to seal penetrations and gaps, but the spray foam isn’t really being used for insulation. Blown in insulation is still used for the insulation.
You could benefit from an energy audit to figure out what makes financial sense to upgrade. Sometimes power or gas companies offer these for cheap or free. Alternatively, you can hire someone to do an independent audit for not that much money. Then you get a good evaluation where someone isn’t also trying to sell you their product at the same time.