What's the consensus of this board on these two strategies for reducing my $600+ ac bill last month.

Pros and cons of both treatments.

Radient = Much Cheaper but less effective (But still effective, dont discount that)

Spray On = Much more expensive but much more thermal resistance, covers every nook and cranny and provides an air seal where needed. It also acts as a partial sound barrier and doesn't interfere with radio/tv broadcast signals if that matters to you.

Many correct answers here but if limited to two, that's where this PERSONAL preference solution trail would begin.

1. Staple the radiant sheets to rafter undersides, insuring a soffit to ridge vent clear path of air.
Now I don't worry with any gas/other appliances in attic venting, etc.
2. Encapsulated (or not if cheaper but hassles are your goals) bag/batt insulation over attic floors, esp. thick over areas that have a lots of windows down there.
3. Any sort of insulation over/around HVAC ducts, after inspecting & sealing properly for leaks.
4. Tarp, tent, shade tree for outside HVAC unit, esp. needed after noon hour.
5. Sign up for 2/year service inspection/maintenance that includes discounted parts, slime-out tabs, etc.
6. Consider other HVAC services.
7. Shade windows, esp. those getting West setting sun rays; Austin Architect study of shaded single pane to exposed double pane windows' solar gain as comparable.
8. Shade exterior walls exposed to West setting sun.

Compare above costs to a new HVAC system, best SEER, variable stage, top-o-line and ask Consumer Reports the best to buy and make money no object to getting the best to defend against more $600 bills (x #-months?) up in smoke.

I got spray foam about a month ago, it's not cheap, but it's great. My AC runs over 25 hrs less per week, and that's with having the thermostat set lower than I normal would. Plus, if there is ever another big freeze, I don't have to worry about any of the plumbing in the attic.

Check with your roofer before doing spray foam in the attic, especially after initial construction. Mine said that only 1 impact resistant shingle is rated (for warranty purposes) to be installed over a sprayed attic, and then it had to meet somewhat strict installation & ventilation guidelines.

What's your insulation situation? That's going to be your best bang-for-buck there.

Vernada said:

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What's your insulation situation? That's going to be your best bang-for-buck there.

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This. Just getting new blown in insulation can make a big difference. And much cheaper than spray foam.

House only has standard batting installed in attic. Small portion of attic (maybe 15%) has radiant barrier because this was an addition approx 8 years ago.

A/C unit in good shape but is 18 years old. I have a service contract and HVAC is inspected semi-annually. Currently in the middle of $18k patio cover installation so I need at least one more year with existing a/c.

Getting bids on spray on barrier and spray on foam.

Other issue: have both a fridge and stand up freezer in detached garage, so will probably will do the same treatment in garage attic.

Where are you located/who did yours? I'm considering this as we're discussing reclaiming some decked attic space. I know that area will always be hot unless i do something.

Houston. Koala Insulation

Thanks

Remember if you're trying to seal your attic you then have to vent the furnace out of the roof if it's 80% or less. It's so much more expensive than just spraying foam and what not.

.... and the verdict IS ......??
Any costs to share?

mosdefn14 said:

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Check with your roofer before doing spray foam in the attic, especially after initial construction. Mine said that only 1 impact resistant shingle is rated (for warranty purposes) to be installed over a sprayed attic, and then it had to meet somewhat strict installation & ventilation guidelines.

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I've also heard that getting a warranty replacement on the shingles is a pain in the ass and not really worth it.

If a hot roof shortens the life of the shingles it doesn't matter much to me. Homeowners insurance companies are probably going to make me replace my roof every 15 years whether I need it or not...

htownag10 said:

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Remember if you're trying to seal your attic you then have to vent the furnace out of the roof if it's 80% or less. It's so much more expensive than just spraying foam and what not.

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I'm going with a heat pump.

1st guy I talked to flaked out and never called me back after he came and looked at my attic.

Currently building a patio cover and the contractor said he will give me a couple of referrals

So, nothing to report so far

I hope you weren't talking to my good friend Ben, he owns and operates a Koala spray insulation business in the Houston area, but he isn't the only one.

If you weren't, give him a call at 214-243-8472. He's an Ag c/o '08 and a stand up guy in every way.