It is one of the most common questions we get asked standing in a furnace room, and the honest answer has two halves. Alberta's building code does set a number for attic insulation — and for Edmonton it is higher than most people expect. But that number applies to houses being built now. Nobody is going to knock on your door and require you to top up an attic that met code the year it was framed. What the code gives you is a benchmark, and a ruler gives you the rest.
What the code actually says for Edmonton
New housing in Alberta is governed by Section 9.36 of the National Building Code – Alberta Edition, the energy-efficiency section. It divides the province into climate zones by heating degree days, and Edmonton and the surrounding area fall into Zone 7A. The attic requirement in that zone depends on one thing: whether the house has a heat recovery ventilator.
That HRV allowance is worth understanding, because it explains why two houses on the same street can legitimately have different attics. The code lets a builder trade improved ventilation against envelope performance. A home with an HRV can meet code at roughly R-49; the same home without one needs closer to R-59. Neither is cutting corners — both are compliant paths.
The part almost everyone gets wrong
Section 9.36 applies to new construction and substantial renovations. It is not retroactive. If your house was built in 1994 to the standard of 1994, it is not "out of code" today and there is no obligation on you to change anything. Contractors who tell a homeowner their attic "doesn't meet code" as a reason to buy are being loose with the word. The code is a useful benchmark for deciding what good looks like. It is not a rule you are breaking.
Effective R-value is not the number on the bag
The code says effective thermal resistance, and that qualifier does a lot of work. Effective R accounts for the whole assembly — including the parts that are not insulation. Framing members conduct heat far better than the material between them, so every joist, truss chord and top plate is a small thermal shortcut. Add the gaps around penetrations, the compressed insulation at the eaves and the wind-washing where outside air blows through the first few feet of the attic, and the assembly performs below what the material alone would suggest.
So should you aim for R-50 or R-60?
For a retrofit on an existing Edmonton-area home, both are defensible and the honest answer depends on what you are optimising for.
| Target | Case for it | Case against |
|---|---|---|
| R-50 | Qualifies for CEIP financing. Roughly 14 inches of settled cellulose. Captures most of the available saving, because insulation follows diminishing returns hard | Leaves some performance on the table on a house you may not touch again for thirty years |
| R-60 | Matches where new construction lands. About 17 inches. The marginal material cost is small once the crew and equipment are already on site | The extra R-10 saves very little on its own — the first R-20 does most of the work |
Our own view, and it is a view rather than a rule: if you are already paying for the mobilisation, the trailer and the crew, the incremental cost of going from R-50 to R-60 is mostly material, and it is the cheapest R-value you will ever buy. But if budget is the constraint, R-50 is not a compromise — it is the threshold the financing programme itself picked, and it captures the great majority of the benefit.
How to measure what you actually have
You do not need a contractor for this. A rigid ruler or a piece of dowel with marks on it, pushed down to the drywall in three or four places away from the hatch, tells you nearly everything. Measure away from the hatch because the insulation there is always disturbed, and take more than one reading — attics are rarely even.
Telling the two apart is easy once you know: cellulose is grey, dense, slightly fibrous and looks like shredded newspaper, because it is. Blown fibreglass is pale yellow, white or pink, much lighter, and springs back when you press it. If you find loose grey-brown pebbles that look like mica or tiny accordions, stop — that is vermiculite, and it needs testing before anyone disturbs it.
What this means if your house is already standing
Forget the code number for a moment and use these three questions instead. They are what actually determines whether topping up is worth doing on your house.
- What does the ruler say? Under 8 inches is where the arithmetic is genuinely compelling. Between 8 and 12 inches there is a real case. Above 12 inches, the gas savings alone will not carry the decision and you should be buying for a different reason.
- When was the house built? Pre-1980 attics were often specified at R-12 to R-20 and have been settling ever since. 2000s homes were built to a much higher standard and rarely need attention. This matters more than the current depth reading, because it tells you what has already been lost.
- What are you actually heating with? On cheap Alberta natural gas, the payback on a modern home is measured in decades. On propane or electric heat — common on acreages around Parkland, Sturgeon and Leduc counties — the same job pays back three to four times faster, and the conversation changes entirely.
And there is a fourth reason that has nothing to do with energy at all. If your ceiling has ever stained after a thaw, the problem is probably air leaking into a cold attic rather than a lack of insulation — and adding insulation without dealing with that first can make it worse. We wrote about attic rain in Edmonton homes because it is the most misdiagnosed thing we see all winter.
The financing threshold is a real number
If the cost is what is stopping you, Edmonton's Clean Energy Improvement Program finances eligible envelope upgrades through the property tax bill rather than up front — but the finished attic has to reach R-50 or better to qualify. That is the practical reason R-50 shows up as a target so often: it is not a code number, it is a financing number.
Two caveats worth knowing before you build a plan around it. Intake capacity moves with funding cycles and the programme has run waitlists, so confirm current status with the City directly rather than trusting a contractor's website. And not every municipality in the greater Edmonton area participates — the programme is administered municipality by municipality.
We Will Tell You The Number
Home Pros Group has cleaned furnaces and ducts across the Greater Edmonton Area under the same name since 2002. Our technicians are inside several hundred local attics a year, which means we have a fairly good sense of what a 1978 bungalow in Spruce Grove has up there versus a 2011 build in Beaumont.
From October 2026 every residential furnace and duct cleaning includes a free Attic Health Check: measured depth in several spots, photographs of what is actually there, the material identified, and a one-page report emailed to you. No charge and no obligation — and if your attic is already fine, that is what the report will say.
Furnace and duct cleaning for a single-furnace home is a flat $345 + GST, in writing before we arrive.
And we now do the work as well as the measuring. If the reading comes back short, blown-in attic insulation tops you back up to R‑50 or R‑60 in fibreglass or cellulose, quoted as one flat number after the free inspection. Where the old material has been wet, matted flat or lived in, it has to come out first — that is insulation removal, vacuumed under sealed containment. We do attics only, and we do not touch vermiculite.
See How Attic Insulation WorksFrequently asked questions
Is my house out of code if the attic is below R-50?
No. Section 9.36 applies to new construction and substantial renovations, not retroactively to existing homes. A house built to the standard of its day remains compliant. Anyone using the phrase "doesn't meet code" to sell you a top-up on an existing house is stretching the term.
Why do some new Edmonton homes have R-49 and others R-59?
Because the code allows a trade. In Zone 7A the attic requirement is an effective R-59 without a heat recovery ventilator, or R-49.2 with one. A builder installing an HRV can meet the energy target with less attic insulation. Both are compliant paths, and neither is a shortcut.
What is the difference between nominal and effective R-value?
Nominal is what the material would deliver on its own. Effective is what the whole assembly delivers once framing, gaps around penetrations, compression at the eaves and wind-washing are accounted for. Code requirements are written in effective terms, which is why a compliant attic is usually blown deeper than the bag maths alone would suggest.
How do I tell cellulose from blown fibreglass?
Cellulose is grey, dense and fibrous — it looks like shredded newspaper because that is what it is. Blown fibreglass is pale yellow, white or pink, noticeably lighter, and springs back when pressed. The distinction matters because cellulose delivers roughly R-3.6 an inch and fibreglass closer to R-2.7, so the same depth is a different R-value.
Is R-60 worth it over R-50?
Marginally, and mostly because of when you are buying it. Insulation follows diminishing returns, so the last R-10 saves far less than the first. But if a crew and equipment are already on site, the incremental cost is largely material — which makes it the cheapest R-value in the job. If budget is tight, R-50 is a perfectly sound stopping point and it is the CEIP threshold.
I found grey pebbles that look like mica. What is that?
Possibly vermiculite, which was used in Canadian attics for decades and some of which contains asbestos. Do not disturb it, do not vacuum it, and do not let anyone blow over it without testing first. It needs to be sampled by a qualified lab, and if it tests positive the work belongs to a licensed abatement contractor — not to us and not to any insulation company.
Check This Yourself
The code documents and financing details behind the numbers above. None of these organizations are affiliated with Home Pros Group.
Book a cleaning, get the number free
Home Pros Group has cleaned furnaces, ducts and HVAC systems across Spruce Grove, Stony Plain and the Greater Edmonton Area since 2002 — flat rates, insured crews, no upsell script. From October 2026 every residential job includes a free Attic Health Check with photos and measured insulation depth. Call 780-932-7337 or request a free quote.
This article is general information for homeowners and is not a code interpretation, an engineering assessment or a building permit opinion. Code requirements are summarised from Section 9.36 of the National Building Code – Alberta Edition as published in the guidance linked above; the authority having jurisdiction in your municipality is the only body that can rule on compliance for a specific project, and requirements change between code cycles. Depth-to-R conversions are approximate and vary by manufacturer, installed density and degree of settling — check the product's own coverage chart for anything you are relying on. Financing availability through the Clean Energy Improvement Program changes with funding cycles and is administered municipality by municipality; confirm current status directly.