Why Is My House So Cold? 7 Causes of a Cold House in Alaska
If your house in Kenai, Soldotna or anywhere in Alaska feels cold even with the heat running, the problem usually isn't the heater. It's heat loss. Warm air is leaking out through gaps, thin insulation, old windows and the roof faster than your system can replace it.
The good news: most of the causes are easy to find once you know where to look. Below are the 7 most common reasons Alaska homes stay cold, plus simple fixes you can start this weekend.
Alaska winters test every part of a house, starting with the roof. Photo: 138 Construction.
In This Article
Quick answer: the 7 causes
Why Alaska houses are hard to keep warm
Causes #1–#7, with fixes
10 easy ways to keep your house warm
FAQ
When to call a pro
Quick Answer: Why Is My House So Cold?
In Alaska, a cold house almost always comes down to one or more of these:
Air leaks letting warm air escape and cold air in
Poor or settled insulation, especially in the attic
Drafty windows and doors
Cold floors from an uninsulated crawlspace
A heating system that's undersized, dirty or failing
Ice dams, moisture and poor roof ventilation
Wind exposure on certain rooms and walls
Start with air leaks and the attic. They're usually the biggest and cheapest fixes.
Why Are Houses in Alaska So Hard to Keep Warm?
The temperature gap. Heat always moves from warm to cold, and the bigger the difference, the faster it moves. When it's 70°F inside and well below zero outside, your house loses heat far faster than a home in a mild climate. Every small gap and thin spot matters more.
Our conditions stack up:
Long winters. The heating season runs most of the year, so small losses add up to big fuel bills.
Wind. Wind off Cook Inlet and open ground pushes cold air through every crack.
Short days. Little winter sun means almost no free solar heat.
Frozen ground. Cold soil pulls heat out of floors and foundations.
Older homes. Many Peninsula homes were built before today's energy standards and have settled insulation, older windows and leaky framing.
Cause #1: Air Leaks Make Your House Drafty
Air leaks are the number one reason Alaska homes feel cold. Even a well-insulated house stays chilly if warm air can slip out.
How the stack effect works. Warm air rises. In winter it pushes out through gaps in your ceiling and attic, and that pulls cold outside air in through gaps near the floor. The colder it is outside, the stronger the pull. That's why your feet feel the draft first.
Where to look for leaks:
Attic hatches and pull-down stairs
Recessed lights, bath fans and plumbing or wiring holes into the attic
Around chimneys and stove pipes
Outlets and switches on outside walls
Where walls meet the floor and around the rim joist
Around window and door frames
Alaska warning sign: frost in the attic. On a cold day, look at the underside of your roof sheathing and the nails coming through. Frost or ice there means warm, moist air from your living space is leaking into the attic. That same leak is making your house cold and can cause ice dams and rot.
Cause #2: Poor Insulation and House Heat Loss
Insulation slows heat from leaving your house. When there isn't enough of it, or it stops doing its job, heat pours out, mostly through the attic.
Why good insulation stops working:
It settles. Older blown-in insulation packs down over the years and loses thickness.
It gets wet. Moisture from attic air leaks or roof leaks soaks insulation and kills its value.
Air blows through it. Fiberglass doesn't stop air. If warm air leaks into the attic, it carries heat right through the insulation.
It was disturbed. Electricians, cable installers and critters push insulation aside and leave bare spots.
Tip: cold rooms point to missing insulation. If one room is always colder than the rest, check the attic above it and the outside walls. Bare spots and thin areas are common over additions, bonus rooms and closets.
Add attic insulation if your house can take it. Seal the air leaks first, then add insulation. Make sure there's still room for air to flow at the eaves so your roof stays vented. Adding insulation that blocks the soffit vents can trap moisture and cause ice dams. (Luck: if you want to name a target R-value, check the current IRC table for Alaska's climate zone before publishing.)
Cause #3: Drafty Windows and Doors
Windows and doors are thin spots in your walls. Older ones lose a lot of heat, and worn seals let cold air stream in.
Signs your windows and doors are losing heat:
You feel a draft standing near them
Frost or ice builds up on the inside of the glass or frame
Fog or moisture between double panes (a failed seal)
Daylight around the edges of a closed door
Weatherstripping that's cracked, flat or missing
Why every Alaska home needs an arctic entry. An arctic entry is a small enclosed entry with a second door. Every time someone opens the front door, the arctic entry holds the cold air back instead of letting it rush into the house. If your front door opens straight into the living room, an arctic entry is one of the best upgrades you can make.
How new windows can help. Replacing old single-pane or failed double-pane windows with modern, well-sealed units cuts drafts and condensation. Before replacing, try the cheap fixes first: new weatherstripping, caulk around trim, and plastic window film for winter.
Cause #4: Cold Floors and Crawlspace Insulation Problems
If your floors are ice-cold, the problem is likely under the house. Crawlspaces and floors over unheated space lose a lot of heat in Alaska.
Common problems below the house:
No insulation, or insulation that has fallen down between floor joists
Open or broken crawlspace vents letting in winter air
Uninsulated rim joists (the band of framing on top of the foundation)
No vapor barrier over the dirt, so moisture rises into the house
Gaps around pipes and wires coming through the floor
Building on frozen ground. Cold soil and permafrost-prone ground pull heat out of foundations and slabs. Insulating the crawlspace walls and rim joist, and sealing the space, usually works better here than just stuffing insulation between floor joists.
Warning: frozen pipes. Cold crawlspaces are where pipes freeze and burst. If your floors are cold, check that water lines below the house are insulated and protected before the next deep freeze.
Cause #5: Heating System Problems in Alaska Homes
Sometimes the heat source really is the problem. A system that's dirty, undersized or failing can't keep up with an Alaska winter.
Boilers and baseboard heat. Watch for cold baseboards, air in the lines (gurgling or banging), and zones that won't heat. Furniture or curtains blocking baseboards also cut heat output.
Forced-air furnaces. A clogged filter is the most common cause of weak heat. Also check for closed or blocked registers and leaky ductwork running through cold crawlspaces or attics.
Toyo, Monitor and direct-vent heaters. These are common across the Peninsula. Problems include clogged fuel filters, dirty burners and blocked or frosted-over vents outside. Keep the outside vent clear of snow and ice.
Wood and pellet stoves. Wet wood, a dirty chimney or a poorly placed stove can leave far rooms cold. Use dry wood, clean the chimney yearly, and use fans to move heat around.
Other common culprits:
A thermostat in the wrong spot, like near a stove or in direct sun
A system sized for a smaller house before an addition
Low fuel, or fuel gelling in extreme cold
Tip: get an annual tune-up. Have your heating system cleaned and checked every fall, before the cold sets in.
Cause #6: Ice Dams, Moisture and Poor Roof Ventilation
Ice dams and icicles aren't just a roof problem. They're a sign your house is losing heat through the attic.
How ice dams form. Heat leaking into the attic warms the roof deck. Snow on the roof melts, runs down to the cold eaves, and refreezes into a ridge of ice. Water then backs up behind the ice, under the shingles, and into your walls and ceilings.
Signs of a moisture problem:
Thick icicles or ice ridges along the eaves
Frost on attic nails and sheathing
Water stains on ceilings or upper walls
Musty smells, mold or dark spots in the attic
Peeling paint near the roofline
The fix: seal, insulate, ventilate. In that order. Seal air leaks into the attic, add insulation, then make sure the roof has balanced intake and exhaust venting so the roof deck stays cold. That's called a cold roof, and it's the best defense against ice dams. Learn more in our Roof Ventilation Guide and Why Hot Roofs Are a Problem in Alaska.
If ice dams have already damaged your roof, a re-roof is the time to add ice and water shield along the eaves and fix the ventilation for good. See Roof Replacement in Kenai & Soldotna.
What years of attic moisture can do: rotten decking found during a tear-off. Photo: 138 Construction.
Cause #7: Wind Exposure and Cold Rooms
The rooms that face the prevailing wind, or stick out from the rest of the house, are almost always the coldest. Wind strips heat off outside walls and forces cold air through every gap.
Design features that make rooms cold:
Rooms over a garage or an unheated crawlspace
Bonus rooms with sloped ceilings and knee walls
Additions built later, often with less insulation
Corner rooms with two or three outside walls
Large windows facing the wind or the water
Vaulted ceilings with little space for insulation
What helps:
Seal and insulate the walls and floors of those rooms first
Add trees, fencing or a shed as a windbreak on the windy side
Heavy curtains or cellular shades on big windows at night
A small direct-vent heater for a room the main system can't reach
How to Keep Your House Warm in Alaska: 10 Easy Fixes
Seal the attic hatch with weatherstripping and add insulation on top of it.
Caulk and foam gaps around pipes, wires, vents and chimneys going into the attic.
Add foam gaskets behind outlet and switch covers on outside walls.
Replace worn weatherstripping and door sweeps on every exterior door.
Put plastic film on drafty windows for the winter.
Change your furnace filter and keep registers and baseboards clear.
Get your heater serviced every fall, and keep outside vents clear of snow.
Insulate the rim joist and close crawlspace vents in winter (if your crawlspace is designed for it).
Close curtains at night and open them on sunny days.
Check your attic on a cold day for frost, wet insulation or bare spots, and fix what you find.
Frequently Asked Questions
Why is my house cold even with the heat on? Usually because heat is escaping faster than your system can make it. Air leaks and attic insulation are the most common culprits.
Why is one room in my house always cold? That room likely has missing insulation, more outside walls, big windows, or sits over a garage or crawlspace. It may also be far from the heat source.
Why is my upstairs warm but my downstairs cold? That's the stack effect. Warm air rises and leaks out up high, which pulls cold air in down low. Sealing attic leaks helps both floors.
Do icicles mean my house is losing heat? Often, yes. Big icicles and ice dams usually mean heat is leaking into the attic and melting snow on the roof.
Is frost in my attic normal? No. Frost on attic nails or sheathing means warm, moist air is leaking into the attic. It should be sealed and the attic ventilation checked.
Will a new roof make my house warmer? A new roof alone won't, but a re-roof is the best time to fix ventilation, add ice and water shield and seal attic leaks, which together reduce heat loss and ice dams.
What's the cheapest way to warm up a cold house? Sealing air leaks. Caulk, foam and weatherstripping cost little and often make the biggest difference.
Should I close my crawlspace vents in winter? In many Alaska homes, yes, but it depends on how your crawlspace was built. Ask a pro if you're unsure, since moisture can become a problem.
Do you work outside Kenai and Soldotna? Yes. 138 Construction works across the Kenai Peninsula, including Nikiski, Sterling and Kasilof, and in Anchorage. Travel and access can affect cost on remote jobs.
When to Get an Alaska Energy Audit or Call a Pro
The easy fixes above handle a lot. Call in help when:
You've sealed and weatherstripped, and the house is still cold
You see frost, mold or wet insulation in the attic
Ice dams come back every winter
You have water stains on ceilings or walls
Pipes have frozen, or floors stay ice-cold
Your fuel bills keep climbing for no clear reason
An energy audit from a certified energy rater uses a blower door test and a thermal camera to show exactly where your house leaks heat. It's the fastest way to know what to fix first. (Luck: if you want to mention Alaska Housing Finance Corporation (AHFC) energy rating programs or rebates, confirm what's currently offered before publishing.)
Call a roofer when the problem is at the top of the house: ice dams, attic frost, poor roof ventilation, or a roof that's leaking or near the end of its life.
The Bottom Line: Stop Losing Heat and Stay Warm This Winter
A cold house in Alaska is almost always a heat-loss problem. Seal the leaks, fix the insulation, tighten up windows and doors, and make sure your roof and attic are vented the right way. Most homes get noticeably warmer, and fuel bills drop.
138 Construction serves homeowners in Kenai, Soldotna, Nikiski, Sterling, Kasilof and Anchorage. We handle roofing, ice dam and ventilation problems, roof snow removal, and residential remodels.
A new, properly vented roof by 138 Construction on the Kenai Peninsula.
Fighting ice dams or a cold, drafty attic? Schedule a roof and attic inspection. From your first call, we can usually get you on the books within 1–7 days.
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