Too hot?
Upstairs is unbearable in July. It is the same attic problem.
The attic that lets your heat escape in January is the attic that cooks your bedrooms in July. Most people treat these as two separate complaints. They are one problem, measured in opposite directions.
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Upstairs is unbearable while downstairs is fine
The single most common summer complaint we get. A Michigan attic reaches 130°F or more on a sunny July afternoon, and there is very little between that heat and your bedroom ceiling.
Attic insulation → -
The AC runs all day and never quite catches up
Same story as a furnace that runs constantly in January, in reverse. The system is removing heat more slowly than the house is gaining it. Adding capacity treats the symptom; slowing the gain treats the cause.
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The room over the garage is the worst in the house
That floor sits over an unconditioned space with almost nothing in it, the walls are often exposed on three sides, and the ceiling is usually a low-slope attic that is hard to reach. It is a genuinely difficult assembly and it needs all three surfaces addressed.
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The house feels humid and sticky even with the AC on
Air leakage is pulling humid outside air in as fast as the AC dries the inside air. Sealing the envelope lets the system dehumidify rather than fight a constant supply of new moisture.
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Some rooms are cold and others are hot at the same time
Usually ductwork rather than insulation — leaky returns, a crushed run, or supply ducts routed through a scorching attic and losing most of their cooling before they arrive.
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The attic smells hot and the roof deck looks dark
The attic is not breathing. Blocked soffit vents — often buried under insulation blown in without baffles — trap heat and moisture against the roof deck, which shortens shingle life as well as cooking the rooms below.
Your attic is around 130°F right now.
On a sunny Michigan afternoon in the high 80s, a poorly ventilated attic runs 40 to 60 degrees hotter than the air outside. That heat sits directly above your ceiling all day and keeps radiating down long after sunset — which is why the upstairs is often worst at 9pm, not 3pm.
- Outside on a hot day
- ~88°F
- An under-ventilated attic
- 130°F+
- What you want the bedroom at
- 72°F
Three ways that heat reaches you
Straight through the ceiling. If the attic floor is at R-13, there is very little slowing a 58-degree temperature difference. This is the one more insulation fixes directly.
Through the gaps. Every hole in your ceiling plane — recessed lights, the bath fan chase, the attic hatch, plumbing penetrations — is a path for superheated attic air to work its way into the rooms below. These are the same leaks that lose you heat in winter.
Through the ductwork. If your supply ducts run through the attic, they are sitting in 130-degree air. Leaky or under-insulated ducts deliver air noticeably warmer than what left the air handler, and any return-side leak actively pulls attic air into the system.
The same leaks, working the other way
These are the points we seal before any insulation goes down. In winter they let your heat out. In summer they let the attic in.
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1 Top plates
The seam where interior walls meet the ceiling, open the length of every wall.
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2 Recessed lights
Dozens of holes in the ceiling plane. Older housings cannot be covered safely.
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3 Plumbing & wiring
Every pipe and cable through the ceiling leaves a gap around it.
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4 Bath fan & chase
Often the biggest single hole, and sometimes venting into the attic instead of outside.
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5 Attic hatch
Usually uninsulated and unweatherstripped. An open door to the attic.
Ventilation is half the answer
An attic is supposed to run close to outdoor temperature. Air enters low at the soffit vents, warms, rises, and leaves high at the ridge. When that path works, the attic might sit 10 or 15 degrees above outside instead of 50.
The most common thing we find is soffit vents completely buried under insulation that somebody blew toward the eaves without installing baffles. The homeowner paid for depth and unknowingly bought a hotter attic and a damper roof deck. Baffles cost very little and they are non-negotiable on any job we do.
What we would do
- Clear and protect the ventilation path. Baffles at every eave so the soffits can actually breathe.
- Seal the ceiling plane. The same work that stops winter heat loss stops summer heat gain.
- Bring the attic to depth with blown cellulose, over the existing material in most homes.
- Flag the ducts. We do not do HVAC, but we will tell you when the ductwork is a bigger problem than the insulation.
It is the same scope of work as the winter fix, which is the good news: one job, both seasons. See the cost guide for ranges, or the rebates page — DTE pays up to $600 on qualifying work regardless of which season prompted the call.
Hot house questions
Does attic insulation actually help in summer, or only winter?
Both. Insulation resists heat moving through a surface in whichever direction it is travelling — out of the house in January, into the house in July. The reason it feels like a winter product is that the winter temperature difference in Michigan is much larger, so the effect is more dramatic. But a 130°F attic over a 72°F bedroom is still a 58-degree gradient, and thin insulation does very little about it.
Would a bigger air conditioner fix it?
It would mask it, expensively. An oversized system short-cycles: it cools the air quickly, shuts off before it has removed much moisture, and leaves the house cold and clammy rather than comfortable. Reducing the heat coming in lets a correctly-sized system run longer, dehumidify properly and cost less to run.
What about an attic fan?
They are more controversial than the marketing suggests. A powered attic fan can depressurise the attic enough to pull conditioned air up out of your living space through the same ceiling gaps we would otherwise be sealing — meaning you pay to cool air that gets sucked into the attic and thrown outside. Sealing the ceiling plane and making sure the passive soffit-to-ridge ventilation actually works is the safer sequence.
Is ventilation or insulation the answer?
They do different jobs and neither substitutes for the other. Ventilation keeps the attic close to outdoor temperature and carries moisture away. Insulation slows the heat that still gets through into your rooms. Air sealing stops the two spaces from exchanging air at all. A good job does all three, in that order of dependency.
Can you do this work in the summer?
Yes, though attics get genuinely dangerous in mid-afternoon heat, so summer work usually starts early. If you are reading this in July because your upstairs is miserable, that is honestly the best time to book — you are experiencing the problem, and the work will be done before the heating season.
Book it now, feel it this summer.
Free measured assessment. We check the depth, the air sealing and whether your soffit vents are buried — then tell you what is worth doing.