2026-04-18 6 min read
There's a reason heating costs in New Hampshire consistently rank among the highest in the country: the winters are long, genuinely cold, and unforgiving of energy leaks. In Farmington. tucked in the hills of Strafford County with lows that can hit the single digits by January. one of the most overlooked sources of heat loss is sitting right in your driveway.
Your garage door is the largest moving part of your home and, in most cases, the largest single opening in the building envelope. If it's uninsulated, you're losing heat every hour of every cold night.
Farmington's climate is classified in IECC Zone 5. the same category as Chicago and Minneapolis. In practical terms, that means your home's heating systems work hard from October through April, and sometimes longer. The town sits inland from the seacoast, so it doesn't benefit from the moderating effect you'd get in Portsmouth or Hampton. It gets colder, stays colder, and the freeze-thaw cycle is intense.
Many Farmington homes. the Colonials, ranch-styles, and Saltbox houses that make up much of the town's housing stock. have attached garages. That means the wall between your garage and your living room is carrying a thermal load every winter night. If your garage door has no insulation, or minimal insulation, that wall is working overtime.
The good news: this is one of the more affordable home energy improvements you can make, and the payoff shows up on your heating bill.
R-value measures how well a material resists heat flow. Higher number = better insulation. That's really all you need to remember.
A single-layer steel garage door with no insulation has an R-value of essentially zero. It's a thin metal panel between you and the outside air. Compare that to:
- R-6 to R-8: Basic polystyrene (foam board) insulation. Better than nothing, reasonable for a detached garage. - R-10 to R-12: Good polystyrene or thin polyurethane. A solid choice for attached garages with moderate heating concerns. - R-13 to R-18+: Thick polyurethane foam injection. The right choice for attached garages in cold climates, or any space used as a workshop or gym year-round.
For most Farmington homeowners with an attached garage, aim for at least R-12. If you have a bedroom above the garage. common in the two-story Colonials along downtown's side streets. go higher. That cold air migrating through the door affects the floor above it directly.
This comes up in almost every conversation about insulated doors, and it's worth being clear about it.
Polystyrene is the rigid foam board material. similar to the foam in a coffee cup or a shipping box. It's fitted into panels inside the door. It works, it's affordable, and it's what you'll find in most mid-range doors.
Polyurethane is injected as a liquid foam that expands and hardens inside the door cavity, filling every gap. It has a higher R-value per inch of thickness, bonds to the steel panels (making the door stiffer and more resistant to denting), and performs better in the sustained cold you get in central New Hampshire winters.
For Farmington's climate, polyurethane is worth the modest price premium if you're replacing a door in an attached garage. The structural benefit alone. a door that holds its shape through the freeze-thaw cycle. makes the upgrade worthwhile.
One thing that often gets overlooked: weatherstripping matters as much as the door itself. A high-R-value door with worn or damaged weather seals at the bottom and sides is still leaking cold air into your garage. Before investing in a new door, check whether a seal replacement might address part of the problem. Our winter garage door problems guide covers this in more detail.
If your current door is in good mechanical condition but has no insulation, retrofit kits are available. These involve cutting foam board panels and fitting them into each door section. It's a DIY-friendly project that takes a few hours and can bring an uninsulated door up to roughly R-4 to R-8.
The catch: adding insulation adds weight, typically 15 to 30 pounds on a two-car door. Your springs are calibrated to the door's original weight. Too much added weight without adjusting the springs can strain your opener motor and create balance problems. If you go the retrofit route, have a technician check your spring tension afterward. You can learn more about spring health in our post on garage door spring warning signs.
If your door is older than 15 years, warped, or showing rust, it's usually more cost-effective to replace it with a factory-insulated model than to retrofit. A new insulated two-car door installed runs roughly $800 to $2,500 depending on the insulation level and door style.
Here's what to actually do, in order:
1. Check your current door's R-value. Look for a sticker inside one of the door panels, or contact Garage Door Farmington to have it assessed. 2. Inspect your weather seals. Run your hand along the bottom edge and sides when the door is closed. Feel cold air? The seals need replacement. this is cheap and makes an immediate difference. 3. Consider how you use the garage. Storage only? R-10 is fine. Workshop or home gym? Go R-16 or higher. 4. Factor in the opening above the door. The gap between your door and the framing (called the headroom) also needs to be sealed properly. Even a great door leaks if the surrounding framing has gaps. 5. Ask about door thickness. A thicker door can accommodate more insulation. Some premium doors are 2 inches thick vs. the standard 1.75 inches. that extra quarter inch makes a real difference at R-18 levels.
If you're not sure where to start, our team can walk you through the options during a free assessment. Visit our services page to see what's available, or reach out directly to schedule a look.
Q: Will an insulated garage door actually lower my heating bill in Farmington? A: Yes, particularly if your garage is attached to your home. Estimates vary, but insulating an attached garage. including the door. can reduce energy loss through that part of the home noticeably. The exact savings depend on how well the rest of your garage is insulated and how airtight your door seals are.
Q: Is there a difference between a 2-layer and 3-layer insulated door? A: Yes. A 2-layer door has steel on the outside and insulation on the inside, but the interior surface is exposed foam. A 3-layer door adds a steel or vinyl backing layer on the inside, which protects the insulation, improves the door's structural rigidity, and generally produces a higher R-value. For Farmington winters, the 3-layer construction is the better long-term choice.
Q: Can I get an insulated door that still matches my older Farmington home's style? A: Absolutely. Most manufacturers offer insulated doors in carriage-house and raised-panel styles that complement Colonial and traditional New England architecture. Steel doors with embossed wood-grain finishes are a popular choice. they handle moisture well and don't require the seasonal maintenance that real wood demands in this climate.