Energy Savings Beyond Solar: What's Worth It?

What else can save you money on energy (besides solar)?

Solar is one of several big-ticket energy investments homeowners make. Often, other measures have shorter payback periods or work alongside solar to reduce total system size needed. Here's the complete 2026 cost-benefit comparison.

The ranking: best ROI energy investments (2026)

Savings vary by climate, home size, current rates, and existing systems.

Insulation

Attic insulation (highest priority)

• Most cost-effective insulation upgrade.
• Add to existing R-13 to bring up to R-49 (cold climate) or R-30 (warm).
• Cost: $1.50-3.00/sq ft installed.
• Federal tax credit (25C, was Energy-Efficient Home Improvement Credit): 30% up to $1,200/yr through 2032.
• Reduces both heating and cooling load.
• Reduces solar system size needed by 5-15%.

Wall insulation

• Blown-in cellulose for retrofit through small holes drilled in walls.
• Cost: $4-8/sq ft of wall.
• Less impactful than attic but still substantial.
• Best paired with new windows or siding work.

Basement / crawl space

• Rim joist + foundation: stop heat loss at floor edges.
• Cost: $500-1,500 for rim joist; more for full foundation.
• Often overlooked; high-value where applicable.

Spray foam

• Closed-cell: superior thermal + air seal; expensive ($3-7/sq ft).
• Open-cell: less expensive, less effective ($1-3/sq ft).
• Used for attic conversions, vaulted ceilings, complex retrofit.

Windows

Energy-efficient window upgrade

• Double-pane low-e: standard since 2000s. Replaces old single-pane.
• Triple-pane (cold climate): additional ~10% efficiency over double-pane.
• Cost: $500-1,500 per window installed.
• Savings: $50-150/window/yr (cold climate) or $30-100/window/yr (warm climate).
• Payback: 15-30+ years — often the WORST ROI of any major energy improvement.

When window upgrade IS worth it

• Original windows are single-pane, leaky, or rotting.
• You're replacing for non-energy reasons (aesthetic, sound, maintenance) anyway.
• You qualify for state energy rebates that cover 30-50% of cost.
• Window upgrade is bundled with full home renovation.

When NOT to upgrade

• Existing windows are decent double-pane and intact.
• Selling home in <5 years.
• Pure energy ROI motivation.

Better-than-windows tweaks

• Window film: reflective film for sun-facing windows. $4-12/sq ft. Reduces summer cooling load 5-15%.
• Cellular shades / honeycomb shades: adds R-3 to R-5 of insulation. $50-300/window.
• Heavy curtains: minimal cost, modest benefit.
• Storm windows: add over single-pane; $200-500/window. Better ROI than full replacement.

Heat pumps (heating and cooling)

Air-source heat pump (ASHP)

• What it is: reverses traditional AC; can both heat and cool.
• Cost: $8,000-18,000 installed (replacing existing HVAC).
• Federal tax credit: 30% up to $2,000 (25C credit) through 2032.
• State incentives: $1,500-8,000 in many states (Inflation Reduction Act, IRA).
• Cold-climate models: Mitsubishi Hyper-Heat, Daikin Aurora, Fujitsu, Carrier Greenspeed effective to -15°F to -25°F.
• Best for: homes currently heating with electric resistance or expensive propane/oil.
• Annual savings vs gas: often modest in cheap-gas regions; significant where gas is expensive.
• Annual savings vs propane/oil: $1,000-3,000 typical.
• Annual savings vs electric resistance: 50-70% reduction in heating bill.

Mini-split (ductless heat pump)

• Single-room or zone heating/cooling.
• Cost: $4,000-7,000 per zone.
• Excellent for additions, garages, or homes without ductwork.

Geothermal (ground-source heat pump)

• Highest efficiency (COP 3-5).
• Cost: $20,000-50,000 for residential install.
• Long payback but lowest operating cost.
• Best ROI in extreme climates with limited fossil fuel access.

Heat pump water heater (HPWH)

• What it is: uses heat pump to heat water (not just resistance).
• Cost: $1,500-3,500 unit + $500-1,500 install = $2,500-4,500 net (after rebates).
• Brands: Rheem ProTerra, AO Smith Voltex, Bradford White Aerotherm.
• Efficiency: 3-4x more efficient than resistance electric.
• Annual savings: $200-400 vs resistance; $50-150 vs gas.
• Federal tax credit: 30% up to $2,000 (25C credit).

Solar thermal water heater

• What it is: rooftop collectors heat water directly via solar (not electric).
• Cost: $5,000-10,000 installed.
• Annual savings: $200-400 vs gas/electric resistance.
• Better alternatives in 2026: heat pump water heater + photovoltaic solar (electricity covers many uses, not just hot water).
• Best for: off-grid systems where electricity is constrained.

Induction cooktop

• $1,200-3,000 (vs $400-800 for gas range).
• $100-200/yr savings vs electric resistance.
• $0-50/yr vs gas (depending on local rates).
• Federal tax credit: 30% up to $840 (25C credit) for ENERGY STAR units.
• Better future-proofing for fully-electrified home with solar.

EV (replaces gasoline costs)

Not strictly "energy savings" but the largest operating cost reduction available:

• 15,000 mi/yr at 30 mpg gas car: 500 gal × $3.50 = $1,750/yr fuel.
• 15,000 mi/yr at 3.5 mi/kWh EV: 4,300 kWh × $0.15 = $645/yr (home) or $0 net if covered by solar production.
• Annual savings: $1,100-1,750.
• Plus reduced maintenance (no oil changes, brake life 2-3x longer).

Smart thermostats

• Brands: Nest, Ecobee, Honeywell Lyric, Sensi.
• Cost: $200-300.
• Savings: 8-15% on heating/cooling = $80-180/yr typical.
• Payback: 1-3 years.
• Bonus: often free from utility company (energy efficiency program).

The package approach: deep energy retrofit

Doing multiple improvements together saves more than doing one at a time:

Sample $30,000 package

• Air sealing: $1,500
• Attic insulation R-49: $3,000
• Smart thermostat: $250
• LED lighting: $300
• Heat pump (ASHP): $14,000 (with $5,000 rebate, net $9,000)
• Heat pump water heater: $3,500 (with $1,000 rebate, net $2,500)
• Window film for 6 sun-facing windows: $1,000
• Total net cost: $17,550
• Combined annual savings: $1,400-2,500
• Payback: 7-13 years

Solar-then-package combo

• Solar 8 kW: $25,000 ($25,000 net post-25D)
• Energy efficiency package: $17,550
• Total: $42,550
• Combined annual savings: $3,000-4,500
• Payback: 10-14 years

Why combo beats solar-only

• Energy efficiency reduces consumption — smaller solar system needed.
• Reduced consumption means more solar exports.
• Combined federal/state incentives stack.

Federal incentives in 2026

• 25C Energy Efficient Home Improvement Credit: 30% up to $1,200/yr for insulation, air sealing, windows, doors, smart thermostats. Up to $2,000 for heat pumps + heat pump water heaters. (Through 2032.)
• 25D Residential Clean Energy Credit: EXPIRED for solar Dec 31, 2025. Still active for geothermal (limited), small wind, and some other tech.
• HEEHRA (Home Electrification and Appliance Rebate program): state-administered $4,000-8,000 rebates for low-/moderate-income households. Active in many states 2024-2027.
• HOMES (Home Owner Managing Energy Savings): rebates for whole-home energy efficiency improvements with measured savings. State-administered.

State and utility incentives

• State energy efficiency programs (typical $200-2,000/yr available).
• Utility rebates for high-efficiency HVAC, water heaters, appliances.
• Demand response / time-of-use programs (some pay you to shift consumption).
• Mass Save (MA), NYSERDA (NY), Energy Trust of Oregon, MN Power Conservation Improvement Program, Xcel Energy programs.

Frequently asked questions