6 Options – Attic Insulation For Hot Climates like Austin TX

Want to figure out the best attic insulation for hot climates like Austin Texas?  Is the temperature in your living area uncomfortable? Are soaring energy bills burning a hole in your wallet? Are you trying to decide which Attic Insulation Options are right for your budget, savings, and comfort?

#0 No Insulation

Without proper attic insulation: heat comes from the sun, through the roof, attic, ceiling, and into your living area. It heats up your AC ducks and raises the temperature of your cold air.

Investment: 0

Energy Savings: 0

Comfort: 0

#1  Some Insulation

How much insulation is in your attic: 0, 4, 6, 13, or 17 inches?

Investment: 1

Energy Savings: 0-1

Comfort: 0-1

Attic Insulation Austin Texas Minimum R-Value

#2 Proper R38-60 Insulation

Blog: Comparing Fiberglass vs Spray Foam

This reduces heat transfer between living areas and the attic. Check out our blog on comparing fiberglass vs spray foam.

Investment: 2

Energy Savings: 2

Comfort: 2

#3 Attic Vents with Proper Insulation

Attic vents let trapped burning hot air move out of the attic.

Investment: 3

Energy Savings: 2

Comfort: 2

#4 Radiant Barrier, Fan, Vents and Proper Insulation

Add attic fans and radiant barrier to imitate spray foam and reflect heat, to reduce scolding hot attic temps.

Investment: 4

Energy Savings: 3

Comfort: 3

#5 Spray Foam with an Open Envelope

Blog: Comparing Vented vs Sealed Building Envelopes

Spray foam blocks all 3 types of heat.  Spray foam applied to the roof decking it brings attic temps much closer to room temps. This allows your HVAC system to be more efficiently and effective.  With spray foam applied to the roof decking, thereʼs No need for attic fans, radiant barriers, or extra vents.

Investment: 4

Energy Savings: 4

Comfort: 4

#6 Spray Foam with a Sealed / Closed Envelope

A spray foam sealed envelope has water heater and HVAC requirements for safety & air recycling. For example, unless your HVAC unit is 90% efficiency or greater, you cannot have a sealed envelope. Your HVAC unit requires outside air to operate.

If you are having your HVAC unit replaced, be sure to tell the company that you intend to install spray foam, and have a closed envelope. This will change what they offer you, and usually allow you to use a smaller unit.  Check out my blog Comparing Vented vs Sealed Building Envelopes.

Closed envelopes deliver max comfort and energy savings. Attic temps are only a few degrees different than living areas.

Investment: 5

Energy Savings: 5 (Excellent)

Comfort: 5 (Excellent)

What does it all mean?

The best energy savings and comfort option is spray foam with a sealed envelope. It will also deliver the highest return on your initial investment. However, if your envelope cannot be sealed because of an older HVAC unit or Water Heater, then your next best option is to have a vented spray foam attic. This is a much better option than only having R38 blown or batt insulation on the attic floor.

What about adding attic vents, fans, and/or radiant barrier? These options will increase your costs, without significant changes to your comfort and energy savings. In fact, having a vent, fan and radiant barrier added will get you very close to the price point of spray foam insulation.

If you are looking for the cheapest way to get the attic up to compliance with building codes, then you may just want to increate the insulation to an R-value of 38, or about 13 inches of blown insulation. This option will be more costly in the long term.

I generally say, if you are going to live there and pay the bills for 3 or more years, do spray foam. If you are flipping the property or selling it in under 3 years, you are better off going the cheap route with blown in insulation. I hope you now know the 6 popular options with attic insulation for hot climates like Austin TX.


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4 thoughts on “6 Options – Attic Insulation For Hot Climates like Austin TX”

  1. I’m having spray foam installed for about $1,000, but I can’t have the envelope sealed because of my old gas heater. Isn’t it just as good to have fiberglass blown in?

  2. Marco, blown fiberglass alone is about half the price of spray foam. However, since it appear you are meeting the industry’s $1,000 minimum, you must be dealing with a small attic space. In other words, you will still be paying $1,000 to have blown insulation installed. More importantly, if you get blown insulation on the attic floor, instead of spray foam on the roof decks, you are missing out on huge benefits. No your attic won’t be as cool as a conditioned sealed envelope. But, your attic will be significantly cooler than if you had only blown insulation installed in the hot Austin TX climate.

  3. Michael Cavalier

    I get all these styrofoam boxes with a certain medicine in it, and they would fit between my rafters. If I put them there (probably with banding to hole them in place), would it be a fire hazard?

    1. Michael, I recommend that you ask the manufacturer for the Safety Data Sheets on the styrofoam. That will tell you the smoke point temperature, burn rate, and much more. Then you can make an educated decision based on the temperature of your attic.

      Your idea is creative. However, it will not be very effective. You have to consider the R-value of the material, the air infiltration stopping properties, and how you will seal it. Lots to think about. If you are looking for a DIY solution, I suggest you go to Home Depot or Lowes and buy the batt insulation to install. Or if you are serious about the benefits of foam, call a professional in your area.

      Good luck. If you do put your creative idea to work, I’d enjoy seeing some photos, and any updates on results.

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