Why does older housing respond so well?
Seventy percent of LaSalle's housing was built before 1980 and more than a third of the whole town went up in the 1970s. The median home dates to 1974. Nothing else in this service area looks like that.
Housing of that vintage was built to insulation standards well below current targets, and most of it has never been meaningfully upgraded. An attic in a 1974 LaSalle house is the case where measuring, air sealing, and topping up to the current target (R-60, and R-49 only where the insulation carries its full uncompressed depth over the wall top plate at the eaves) does exactly what the brochures claim — because the starting point is genuinely low.
Who in LaSalle should move on this?
Most of the town, honestly. Seven in ten LaSalle homes are in the age band where an attic assessment usually finds a real gap, and the Atmos rebate structure is built for exactly this case, where Atmos serves the home — 75% of cost where existing insulation starts below R-20, which an untouched 1970s attic reliably does, with the current amount published on the Atmos rebate page. Atmos service is not confirmed for every town in this area, so check your own utility before counting on it.
Two cautions specific to older housing. The 11.1% of LaSalle homes predating 1940 may have knob-and-tube wiring that has to be cleared by an electrician before anything is buried, and may have vermiculite that needs lab testing before it is disturbed. Neither stops the project; both change its sequence and its cost, and both should surface in the assessment rather than on install day.
Who should skip it: the roughly quarter of the town built since 2000, on the same logic as anywhere else.
What does insulation work cost in LaSalle, and what does waiting cost?
Cost tracks scope, and scope tracks what the assessment finds — attic square footage, how far below target the existing material sits, whether anything has to come out first, and how much air sealing the ceiling plane needs. A number quoted before anyone has been in the attic is a negotiating position, not a price.
What can be stated precisely is the structure of the rebate, because that is what Atmos publishes and holds steady. Atmos Energy rebates attic insulation at 75% of project cost where existing insulation starts below R-20, and rebates wall, crawlspace or basement, and floor insulation on their own terms. Air sealing is a separate measure and requires a blower door test showing at least a 20% reduction in leakage. The application is due within 60 days of the work, and the installing contractor needs an applicable license — there is no registered-contractor list to navigate. Atmos gas service is confirmed for some towns in this area and not formally confirmed for others, so verify your own service before counting on the rebate.
What each measure pays is the part that changes, so this site does not print it. Atmos publishes the current amounts on its own Colorado residential rebate page, and that is where to read them before scoping work.
The cost of waiting is the part nobody itemizes: every heating season an under-target attic runs, it is paying to warm the space above the ceiling. That is not an argument for urgency — it is an argument for getting the measurement, so the decision is made on numbers rather than on a season of guessing.
Sources
What the data says
According to Atmos Energy, Atmos Energy rebates residential attic insulation at 75% of total cost where the starting R-value is less than R-20, and publishes the amount that rebate currently pays on its own rebate page.
In practice, reaching the penetrations in the ceiling plane means the old loose-fill comes out first — you cannot seal what you cannot see or reach.
According to the International Energy Conservation Code, the 2021 IECC sets a minimum ceiling insulation R-value of R-60 in Climate Zone 5 under Table R402.1.3, and Section R402.2.1 allows R-49 to satisfy that requirement only where the full height of uncompressed R-49 insulation extends over the wall top plate at the eaves.
According to the City of Greeley, the City of Greeley building department publishes a design wind speed of 115 mph, a ground snow load of 30 PSF, a frost depth of 30 inches, a seismic design category of B, and a mean annual temperature of 49 degrees Fahrenheit for construction within the city.
Take the next step
1970s house with an attic nobody has touched?
That is the most common house in LaSalle and the one where this work most reliably pays. The free assessment measures what is up there, flags any wiring or old-material complications before they become surprises, and prices the job with the Atmos rebate applied where Atmos serves the home.
Get a quote
Tell Us About Your Home
30 seconds to fill out. Free quote, no high-pressure follow-up.
We've Got It. Here's What Happens Next.
We've got your info and are routing it to a local pro. When they call, here's what to look for in the quote you receive: (1) R-value target — Greeley builds to the 2021 IECC, which puts attics at R-60, and accepts R-49 only where the insulation carries its full uncompressed depth over the wall top plate at the eaves; anything less is under-spec. (2) Air sealing scope — insulation alone does nothing if air leaks aren't sealed first, so it belongs on the quote as its own line with its own scope, and a blower door test is what documents the before-and-after. (3) Rebate handling — ask who files the rebate paperwork with your gas utility, and confirm what that utility's filing deadline is and that the application will go in inside it. (The federal IRA Section 25C tax credit ended December 31, 2025, and Colorado's HEAR program is closed. Which utility to ask about an insulation rebate depends on your town: Atmos Energy's residential rebates are the primary insulation rebate programs in Greeley, Evans and Eaton, while the natural gas utility is Xcel Energy in Johnstown, for most of Milliken, and for most locations in Severance — Xcel sets out its own insulation and air sealing rebate terms on its rebate page. Income-qualified households can get insulation work done at no cost through the state Weatherization Assistance Program.) (4) Removal scope — older homes often need old insulation removed before new install. If a quote skips all four, get another quote.
Frequently asked
What do LaSalle homeowners ask about insulation?
How much difference does this actually make on a 1970s house?
Enough to be worth doing, though anyone quoting you a precise percentage before measuring your house is making it up. The mechanism is simple: a 1970s attic typically starts well below current targets, and closing a large gap produces a larger effect than closing a small one. The assessment gives you your numbers rather than an average.
Is the Atmos rebate really 75%?
Attic insulation is rebated at 75% of project cost where the starting R-value is below R-20 — which describes most untouched 1970s attics. Air sealing is a separate measure with a blower-door requirement. What either one pays is published on the Atmos rebate page, not here, because those amounts are subject to change and last only while funding does. The other conditions to watch: the premise must be served by Atmos, and the application is due within 60 days.
What if there is old vermiculite up there?
Stop and test before anything else. Vermiculite — small pebbly granules rather than fluff or batts — should be treated as asbestos-containing until a lab says otherwise. Do not disturb it, do not vacuum it, and do not let anyone without CDPHE abatement certification move it. Testing first, CDPHE-certified abatement if positive, insulation afterwards. That is a different trade and a separate contract.
Does knob-and-tube wiring rule out insulation?
It rules out insulating over it while it is live, which is not the same thing. An electrician clears or replaces the active runs, the work is inspected, and the insulator follows. Doing it in the other order means paying to have new insulation pulled back out when the inspection fails, which is how homeowners get hurt on old-house projects.
Air sealing or insulation first?
Air sealing first, essentially always, and especially on housing this age. Sealing the ceiling plane while the attic is accessible is far easier before new material goes down than after, and insulation over an unsealed plane underperforms its rating. Any contractor proposing to blow first and seal never is skipping the cheaper half of the job.
My LaSalle home was built after 2000 — does this apply to me?
Much less. About a quarter of the town is post-2000 and that housing started near current targets. If you are in that group with normal bills, the honest answer is that the case here is much weaker for you than for your older neighbors, and a diagnostic visit is a better use of your time than a project.
How disruptive is the work?
For a straightforward attic job, minimal — equipment stays outside, a hose runs to the attic access, and most houses this size are done in well under a day. It gets longer if electrical work or abatement has to happen first, which is another reason to have the assessment identify those before scheduling anything.
Related guides