Last updated February 2021
Looking for cost-effective ways to reduce your home’s energy consumption? Our section on how to save energy at home shares more than 30 changes that will cut costs—and help the planet—from cheap-yet-effective steps to upgrades that require some upfront spending, but quickly pay for themselves from lower utility bills.
Because heating is by far the biggest energy eater for Twin Cities area homes, typically accounting for nearly 70 percent of utility expenses, it makes sense to focus first on cutting that consumption. For many homes, a big money-saver is to install or add insulation in spots that need it, and to seal cracks and gaps to reduce air leakage. If your home is under-insulated or has a lot of air leaks, heat escapes during winter and your hard-earned money floats away, too. In summer, heat flows into cool spaces in your home, raising your cooling bill.
First, Look for Leaks
Feel drafts in the winter? That’s an obvious sign of leaks. If you consistently get cold between furnace cycles, that’s another sign.
One little leak might not seem like a big deal but having several can add up to the equivalent of leaving open a small window. It usually costs very little money to identify and fix ways your home passively wastes energy, but it yields significant savings.
You can sleuth out major leaks on your own. Turn off your furnace on a cool, very windy day; shut all windows and doors; turn on all exhaust fans that blow air outside, such as bathroom fans or stove vents; light an incense stick and move around your house, watching where smoke blows to identify drafts.
Most leaks occur where different building materials meet—brick and wood siding, foundation and walls, and chimney and siding. Other common problem areas are around windows and doors; mail slots; points of entry for electrical and gas lines, cable/internet wiring, and phone lines; outdoor water faucets; where vents pass through walls; cracks or gaps in siding, stucco, masonry, and all foundation materials; and around window air-conditioning units.
Use caulk to seal any cracks or gaps measuring less than ¼-inch wide, and use polyurethane foam sealant for larger ones.
To minimize leakage around doors and windows, install weatherstripping. Open-cell foams are inexpensive and relatively inefficient but easy to apply and suitable for low-traffic areas. Vinyl is more expensive and lasts longer. Metals last for years and provide a decorative element for older homes. Also add sweeps to the bottoms of all exterior doors to seal gaps there.
Prevent drafts around outlets and light switches located inside exterior walls by adding insulating receptacle gaskets, which cost less than $5 each.
If you have window A/C units, remove them during the winter, or insulate them from the outside with an A/C cover ($20-$60). During summer, install units so they fit tightly within windows.
Together, these measures can save you five to 20 percent on heating and cooling costs.
Want Help? Hire an Energy Auditor
A good energy auditor can track down leaks and use equipment to identify leaks you might not find yourself.
Most auditors offer quick assessments and full inspections. Utility companies often help pay for the quickies—typically, your share of the cost is $100 or even nothing.
A comprehensive audit typically costs $400 to $600, but you’ll get a lot more info out of it. The inspector will examine all features of your residence and evaluate your utility spending for the last year. For a full audit, the company should use a calibrated blower door to measure the overall air leakage of your home and perform a thermographic inspection using an infrared camera. Confirm in advance that it will do these tasks; if not, find another company.
In our energy auditors section we provide customer reviews we’ve collected from local homeowners for auditors they hired. You also may as well hire one certified by the nonprofit Residential Energy Services Network (RESNET). Certified auditors must complete RESNET’s training program and carry a minimum of $500,000 in liability insurance.
Do You Need to Add Insulation?
All structural elements enclosing your home’s living spaces should be insulated. It’s most practical to add insulation when a home is built or during renovations. Otherwise, accessibility drives costs and often determines what’s worth doing.
Because warm air rises, your attic is the front line in the battle to conserve energy during winter. And because most attics are unfinished and contain a lot of empty space, adding a thick layer of insulation is an easy job.
In this region, the U.S. Department of Energy (DOE) recommends attics be insulated at R-49 or better. Check what type of insulation you already have (loose fibers, granules, batts, etc.) and measure its thickness. To achieve an R-49 rating, loose fiberglass particles should be laid at a thickness of about 20 inches, rock wool particles at 17 inches, cellulose (looks like shredded newsprint) at 13 inches, and batts (blankets that come in rolls) at 15 inches.
Unheated areas underneath ground floors, such as crawlspaces and basements, are also good places to add insulation. Crawlspaces should be dry year-round (moisture causes insulation to deteriorate), and a vapor barrier should be placed on the floor of the crawlspace.
If your home was built in the 1970s or later, its exterior walls probably have adequate insulation. If your home is older, it might be worthwhile to install insulation or improve what has deteriorated. To do so, installers have to drill access holes between each pair of wall studs, blow in insulation, and then patch and reseal the openings. This is much more time-consuming, messy, and costly than insulating an open unfinished attic or a crawlspace. But if you’re doing a major renovation or replacing siding, it’s worth adding this task, if needed: For an average-size home in this area, adding R-11 of insulation to uninsulated exterior walls will likely save $300 to $400 in energy costs per year.
Is It Worth It?
Since attics in most homes are easily accessed and unfinished, they’re ideal targets for improving insulation. How much you’ll pay to do this depends on how much you need to add—and whom you hire to do it. The table below reports costs quoted to Checkbook’s undercover shoppers by Twin Cities area contractors to add insulation to increase the rating of a sample unfinished attic from R-11 to R-49. Those prices range from $1,400 to $6,781.
Check with your utility companies for programs that can defray upfront costs: At press time, Xcel Energy and CenterPoint Energy offered rebates for insulation improvements. Most attic projects qualified for rebates of $300 to $750.
Since the work isn’t cheap, even if you hire an inexpensive outfit to do it, is it worth it?
You’ll find lots of online calculators that estimate projected savings and the payback period based on information you provide about your home, current energy prices, and other variables. Many insulation installation companies also provide (often rosy) payback predictions along with their cost proposals. But these projections often vary dramatically from actual experience. We’d particularly avoid calculators or estimates provided by trade organizations.
One useful calculator comes from the Lawrence Berkeley National Laboratory (LBL). Its Home Energy Saver tool gives a full assessment of your current energy use, possible cost savings—including savings from adding insulation—and payback time for efficiency improvements.
Using the Home Energy Saver tool, we found that for a sample area home the energy savings from adding insulation will eventually pay off project costs. For our sample home, improving attic insulation from R-11 to R-49 would generate utility savings of about $220 per year, which would recover $2,000 in installation costs in about nine years.
Hiring an Installer
Quality installation work will maximize the effectiveness of insulation work. Fortunately, several area contractors are equal to the job. Here at Checkbook.org, you can find ratings and reviews submitted by local consumers for companies they used; that feedback is for the most part positive.
Since most insulation contractors seem to do satisfactory work, and because prices vary widely from company to company, get several price quotes. Ask prospective companies how they plan to do the work, what materials they plan to use, and why. Be wary of exaggerated claims of energy savings. Be sure to ask contractors for proof of worker’s compensation and liability coverage.
Get a contract that details the size of the area to be insulated, what type and how much insulation will be installed, and the resulting R-value (required by the Federal Trade Commission). For blown-in loose-fill insulation, the contract should also state the depth in inches of insulation present before new insulation is added and the depth after the work is done. If the company will be sealing cracks and other infiltration points, make sure the contract specifies the location of these areas.
If your project qualifies for a rebate from your utility, confirm that you’ll qualify for the incentive. These programs usually require homeowners to work with utilities’ “approved” contractors or to file paperwork before installations occur to get rebates.
Before work begins, a rep should inspect the jobsite and check for any issues—for example, to make sure there is no exposed wiring in any area. (Insulation cannot be installed over old knob-and-tube-style wiring.)
Other matters to cover in a contract:
- In attic spaces, the contract should promise that the company will keep attic vents free of blockage. Typically, a company will use fiberglass batts to build a dam around spaces that should not be covered by insulation. In addition, be sure the company will insulate the attic’s access panel or pull-down stairway.
- Check for any recessed lighting fixtures (like can lights) that are exposed in the attic. If they are marked “IC” (insulated contact), it means insulation can contact them. If they are not IC-rated, be sure the contractor promises to keep insulation a minimum of three inches away to avoid a fire hazard.
- If ductwork, boiler pipes, or hot-water-supply pipes run through the area to be insulated, the contract should require the contractor to insulate them with R-6 insulation.
- If you will be insulating walls, the contract should specify where the company will create holes, how many, and how the openings will be closed and repaired.
- Reference in the contract a material fact sheet, which the company should attach, describing the insulation that will be installed (contractors are legally obligated to provide a fact sheet, upon request).
- Unless your job requires more than one day’s work (most don’t), don’t agree to pay until all work has been completed.
Before paying, check that all cracks were sealed as agreed upon, that the amount of insulation added matches the proposal, and that loose-fill insulation was applied evenly. Also, make sure the crew has cleaned up the area.