Spray foam vs fiberglass: which is right for your house?
An honest comparison for Central Texas homes. Spray foam wins some jobs, blown in fiberglass wins others, and price is only part of it.
The short answer
If your attic just needs more depth and your ductwork is in decent shape, blown in fiberglass usually gives you the most comfort per dollar. If your ducts run through a hot attic, your upstairs never cools down, your house is leaky or you are insulating a metal building, spray foam is often worth the higher price.
| Blown in fiberglass | Spray foam | |
|---|---|---|
| What it does | Slows heat moving through the attic floor | Slows heat and seals air leaks |
| Where it goes | On the attic floor | Usually on the underside of the roof deck |
| Attic temperature | Attic stays hot, house below is protected | Attic stays much closer to indoor temperature |
| Ductwork in the attic | Still sits in the heat | Inside the sealed space |
| Air sealing | Separate step | Built in |
| Installed price | Lower | Higher |
| Settling over time | Settles slightly | Does not settle |
Six reasons people choose spray foam
And when they should not.
It seals the air leaks
Foam fills gaps and cracks that batts and loose fill leave open.
A cooler attic in August
Foam on the roof deck brings the attic much closer to the temperature inside your house.
Ductwork out of the heat
AC ducts in a sealed attic stop losing cool air to extreme heat.
No sweating metal roofs
Closed cell foam stops condensation in shops and barns.
It does not settle
Foam stays where it is sprayed instead of packing down.
Quieter rooms
Open cell foam softens outside noise through walls and ceilings.
When fiberglass is the better choice
- Your attic is only short on depth. Topping up costs much less and solves the main problem.
- Your ducts are sealed and in good shape, or your air handler is not in the attic.
- Budget comes first. A properly done blown in job is a big upgrade on its own.
- You may re-roof soon. Some homeowners prefer to time roof deck foam with a new roof.
What it means for Bell County homes
Central Texas is cooling country. Long, hot summers push attic temperatures far above the outdoor air, and many homes here have the air handler and ductwork in that attic. That combination is where spray foam on the roof deck tends to make the biggest difference.
Older homes in Temple and Belton often benefit from air sealing as much as from more insulation. Newer two story homes in Harker Heights and Nolanville often have a hot upstairs from long duct runs. Single story homes in Killeen and Copperas Cove with a reasonable attic depth are often well served by a blown in top up and a radiant barrier.
Learn more
See what affects insulation cost. For the difference between the two kinds of foam, read open cell vs closed cell spray foam.
Get a recommendation for your house
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