What does an audit actually measure?
Three things, in rough order of value. Air leakage, via a blower door: a calibrated fan seals into an external doorway, depressurises the house, and measures the airflow needed to hold that pressure. The result is a CFM50 figure — an actual quantity of leakage rather than an impression of draughtiness. With the house under pressure, individual leaks become findable by hand.
Thermal performance, via infrared: a camera reads surface temperature, so missing insulation, settled material, thermal bridging at framing, and empty wall cavities appear as patterns. This is how the wall question gets answered without opening a wall, and it needs a temperature difference between inside and outside to work properly.
And combustion safety, where there are gas appliances: draft testing and spillage checks on the furnace and water heater. This is the part nobody asks about and the part that occasionally matters most, particularly on a house about to be made significantly tighter.
Scope here is retrofit work on homes that are already built and lived in: assessment, removal where the existing material has to come out, air sealing, and installation. New construction runs on a different process and is normally handled through the builder — and it is worth knowing that Atmos excludes residential new construction from these rebates outright, so a new build does not have this money available to it in the first place.
Should you pay for an audit, or start with the free one?
Start with the free one. Atmos Energy offers its residential customers a free home energy assessment along with an energy saving kit. It costs nothing, and for a household that mainly wants to know whether there is a problem worth pursuing, it frequently answers the question. Recommending it first costs this site a referral and is still the correct advice.
The case for paying for a fuller audit is narrower and real. It applies when you need a documented blower door number — which the $575 Atmos air sealing rebate requires, since that rebate is defined by a measured 20% reduction. It applies when several contractors have given you contradictory diagnoses and you want an assessment from someone not bidding the work. And it applies when the house has a persistent comfort problem that the obvious fixes have not solved.
One thing to check before booking: whether the auditor also sells the remediation. That is not disqualifying — plenty of good contractors do both — but an assessment from a party with no stake in the recommended scope is a different kind of document, and if you are paying specifically for an independent opinion it is worth knowing which one you are buying.
What should you get at the end of it?
A prioritised list, with numbers. The blower door result in CFM50. Where the significant leaks are, specifically enough to act on. Measured existing insulation levels by area, expressed as R-values rather than depths. Any combustion safety findings. And an ordering of recommended work by what it costs against what it returns.
What you should not receive is a quote dressed as a report. A document whose findings map exactly onto one contractor's service list, with no measurements attached, is a sales artifact. The test is whether the report contains numbers you could hand to a different contractor and get a comparable bid from.
The audit is also where the honest negative answer comes from. A house that measures reasonably tight with insulation near target does not have an insulation problem, and no amount of quoting will change that. In a town like Severance, where 91.7% of homes were built in 2000 or later, that outcome is common — and being told it plainly is worth more than a proposal you did not need.
Sources
What the data says
According to the Building Performance Institute, “BPI-certified energy auditors use blower door testing to measure air infiltration in CFM50, with most pre-1990 homes registering 2-4x the leakage of modern construction.”
According to the Air Conditioning Contractors of America, “ANSI/ACCA Manual J is the residential load-calculation standard used to size heating and cooling equipment to a specific home envelope, rather than by square-footage rules of thumb.”
According to the Colorado Energy Office, “the Weatherization Assistance Program provides no-cost weatherization services for qualified residents and homes, including insulation in the attic, floors, and walls.”
Take the next step
Want the diagnosis before the proposals?
The free in-home assessment measures existing insulation levels and identifies the obvious loss paths, which is enough to direct most decisions. Where a documented blower door number is what you actually need — for the air sealing rebate, or because diagnoses have conflicted — you will be told that plainly rather than sold a scope.
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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-49 to R-60; anything less is under-spec. (2) Air sealing scope — insulation alone does nothing if air leaks aren't sealed first, and Atmos requires a blower door test to rebate it. (3) Rebate handling — ask who files the Atmos paperwork and confirm it goes in within 60 days of the install. (The federal IRA Section 25C tax credit ended December 31, 2025, and Colorado's HEAR program is closed. Atmos Energy's residential rebates are the primary insulation rebate stack for Greeley-area projects in 2026, and 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
Questions about energy audits
Is there a free energy audit in Greeley?
Atmos Energy offers residential customers a free home energy assessment and a free energy saving kit. That is the sensible first step for most households, and it is worth exhausting before paying for anything. Income-qualified households should also look at the state Weatherization Assistance Program, which includes an assessment as part of free weatherization work.
What is a blower door test?
A calibrated fan sealed into an exterior doorway that depressurises the house and measures the airflow needed to maintain that pressure. The result is a CFM50 number quantifying total leakage. With the house depressurised, individual leaks can be located by hand, which turns a vague draught into a specific list of places.
Do I need an audit before insulation work?
Not always. If the attic is visibly shallow and the house is from the 1970s, the diagnosis is not in much doubt and the assessment that comes with a quote will confirm it. An audit earns its cost when you need a documented blower door number for the air sealing rebate, when diagnoses conflict, or when a comfort problem has resisted the obvious fixes.
How long does an audit take?
Typically two to four hours for a normal single-family home, depending on size, how many combustion appliances there are, and how much of the house is accessible. The infrared portion works best with a meaningful temperature difference between inside and outside, so scheduling in a shoulder season can give weaker results than winter.
Does the audit qualify for a rebate?
The Atmos assessment is free rather than rebated, which comes to the same thing from your side. What the rebate structure does care about is the measurement: the $575 air sealing rebate requires a blower door documenting at least a 20% CFM(50) reduction, so the before-and-after testing has to be part of the plan for that money to be reachable.
Will the auditor try to sell me work?
Some do, since many auditors are also contractors. That is not automatically a problem, but it is worth knowing which you have hired. If you specifically want an independent read, ask up front whether they bid the remediation, and treat a report with no measurements in it as a sales document rather than an assessment.
When is an audit a waste of money?
When you already know the answer. If you can see six inches of insulation in a 1975 attic, an audit will tell you the attic is under-insulated and you will have paid to confirm what you could see. Free assessments and the measurement that comes with a quote cover that case. Pay for an audit when there is genuine uncertainty, not to document the obvious.
What is Manual J and why did someone mention it?
ANSI/ACCA Manual J is the standard for calculating heating and cooling loads for a specific house rather than sizing equipment by square footage. It matters after insulation work because a tightened, better-insulated house needs less capacity than it did — and replacing like-for-like afterwards can leave you with an oversized system that short-cycles.
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