Home Energy Efficiency

Homeowner Summary

Home energy efficiency is about getting the same comfort and functionality from your home while using less energy. The average US household spends approximately $2,000-$2,500 per year on energy, and most homes waste 20-30% of that through air leaks, outdated equipment, phantom loads, and inefficient habits. Improving efficiency is almost always the best first investment — cheaper than solar, more impactful than switching energy suppliers, and it makes every other energy investment work better.

ENERGY STAR, the EPA's efficiency certification program, is the simplest guide for consumers. ENERGY STAR-certified products (appliances, HVAC, windows, lighting) meet strict efficiency thresholds and are typically 10-50% more efficient than standard models. The Home Energy Score (HES), developed by the Department of Energy, rates a home's energy performance on a 1-10 scale, giving homeowners a clear benchmark and prioritized improvement list.

The most impactful improvements, in order of typical ROI, are: air sealing and insulation (20-30% savings), HVAC optimization (10-20%), water heating upgrades (5-10%), lighting conversion to LED (5-10%), and appliance replacement (5-10%). Combined, a comprehensive efficiency overhaul can cut energy bills by 30-50%.

How It Works

Home energy efficiency addresses five interconnected systems, each contributing to total energy consumption:

Building envelope: The walls, roof, foundation, windows, and doors that separate conditioned space from the outside. A tight, well-insulated envelope is the foundation of an efficient home. Air leaks (measured by blower door test) and insulation gaps (visible on thermal imaging) are the most common efficiency failures.

HVAC (Heating, Ventilation, and Air Conditioning): Typically 40-50% of home energy use. Efficiency is rated by SEER2 (cooling), HSPF2 (heat pump heating), and AFUE (furnace/boiler). Modern high-efficiency systems use variable-speed compressors and fans that modulate output to match the actual load rather than cycling on and off.

Water heating: Typically 15-20% of home energy use. Options range from standard tank water heaters (EF 0.58-0.67) to heat pump water heaters (UEF 3.0-4.0, effectively 300-400% efficient). A heat pump water heater can cut water heating costs by 60-70%.

Lighting: Typically 10-15% of home energy use with incandescents, reducible to 2-4% with LEDs. Full LED conversion is one of the fastest-payback improvements.

Appliances and electronics: Refrigerators, clothes dryers, dishwashers, and electronics account for 20-30% of home energy use. ENERGY STAR models are significantly more efficient, and phantom loads (devices drawing power while off) can add $100-$200/year.

Phantom loads (also called vampire loads or standby power) are devices that draw power when turned off or in standby mode. Common culprits: cable boxes (20-30W), game consoles (10-25W), computer monitors (5-15W), phone chargers (1-5W each), and smart speakers (2-4W each). In aggregate, phantom loads can represent 5-10% of a home's total electricity consumption.

Maintenance Guide

DIY (Homeowner)

• Replace HVAC filters monthly during heavy-use seasons, every 3 months otherwise
• Clean refrigerator coils annually (back or underneath, depending on model)
• Set water heater to 120F (factory default is often 140F, wasting energy and creating scald risk)
• Use power strips for entertainment centers and home offices; switch off when not in use
• Run dishwasher and clothes washer with full loads only
• Use cold water for laundry (modern detergents work well in cold water)
• Set ceiling fans to counterclockwise in summer (downdraft) and clockwise in winter (updraft to redistribute warm air)
• Keep dryer lint trap and exhaust duct clean for efficient operation
• Open curtains on south-facing windows in winter for solar gain; close them in summer to reduce cooling load

Professional

• Annual HVAC tune-up: Clean coils, check refrigerant charge, verify airflow, inspect ductwork, calibrate thermostat
• Every 3-5 years: Energy audit to reassess home performance, especially after renovations
• At equipment replacement: Right-size new equipment based on Manual J load calculation (do not simply match the old unit's tonnage)

Warning Signs

• Energy bills increasing year over year without changes in rates or usage patterns
• Rooms that are consistently uncomfortable despite HVAC running
• HVAC running almost continuously in moderate weather
• Water heater recovery time noticeably longer than when it was new
• Refrigerator running constantly or frost buildup in a frost-free model
• Condensation on interior windows in winter (indicates excess humidity from air leakage)
• Utility bill significantly higher than similar-sized homes in your area

When to Replace vs Repair

General efficiency rule of thumb (50% rule): If a repair costs more than 50% of a replacement with a high-efficiency model, and the existing equipment is more than halfway through its expected life, replace.

Replace appliances when:

• Refrigerator is pre-2005 (modern ENERGY STAR uses 40-50% less energy)
• Clothes dryer is pre-2015 (heat pump dryers use 28% less energy)
• Water heater is 10+ years old (upgrade to heat pump water heater for 60-70% savings)
• Dishwasher is pre-2010 (modern units use 30% less energy and 40% less water)

Upgrade HVAC when:

• Furnace AFUE is below 90% (modern units achieve 95-98%)
• AC SEER is below 14 (modern units achieve 16-26 SEER2)
• System is 15+ years old and repair frequency is increasing

Prioritize by ROI: Air sealing, insulation, and LED lighting pay back fastest (1-3 years). HVAC and appliance upgrades pay back in 5-10 years. Window replacement has the longest payback (10-20 years) and should be prioritized last unless windows are single-pane or have failed seals.

Pro Detail

Specifications & Sizing

| Efficiency Rating | Applies To | Good | Excellent | |------------------|-----------|------|-----------| | SEER2 | Air conditioners, heat pumps (cooling) | 15+ | 20+ | | HSPF2 | Heat pumps (heating) | 8.5+ | 10+ | | AFUE | Furnaces, boilers | 92%+ | 96%+ | | UEF | Water heaters | 0.65+ (gas tank) | 3.0+ (heat pump) | | EnergyGuide (kWh/year) | Refrigerators | < 500 | < 350 | | CEF | Clothes washers | 2.2+ | 2.8+ | | EF | Dishwashers | 0.87+ | 0.95+ | | R-value | Insulation | R-38 attic (CZ3) | R-60 attic (CZ5+) | | U-factor | Windows | 0.30 | 0.20 | | SHGC | Windows (solar heat gain) | 0.25-0.40 | Climate dependent |

Home Energy Score (HES): DOE's 1-10 scoring system based on the home's physical characteristics (envelope, equipment, location). Score of 1 = very inefficient; 10 = very efficient. Median existing US home scores approximately 3-5. Assessments take 1-2 hours and cost $100-$300.

ENERGY STAR certification levels:

• ENERGY STAR Certified: Meets minimum efficiency thresholds (varies by product)
• ENERGY STAR Most Efficient: Top tier within ENERGY STAR (typically top 10-15%)

Common Failure Modes

• Envelope degradation: Caulk cracks, weatherstripping compresses, insulation settles. Efficiency degrades gradually over 5-15 years without maintenance.
• HVAC efficiency decline: Dirty coils, low refrigerant, worn components reduce actual efficiency below rated levels. A 16-SEER system with dirty coils and duct leaks may operate at effective 10-12 SEER.
• Duct leakage: The number one hidden efficiency killer. Ducts in unconditioned spaces lose 20-30% of conditioned air through leaks. Every home with attic or crawlspace ducts should have duct leakage testing.
• Oversized HVAC: Equipment selected based on rules of thumb rather than Manual J calculations is often 30-50% oversized. Oversized equipment short-cycles, reduces dehumidification, and wastes energy.
• Phantom load creep: Each new electronic device adds to the always-on load. Homes accumulate phantom loads over time without awareness.
• Window seal failure: Double-pane windows develop condensation between panes when the seal fails, reducing insulation value from roughly R-2.5 to R-1.5.

Diagnostic Procedures

1. Utility bill benchmarking: Compare 12 months of energy use to similar homes (size, climate zone, fuel type). Many utilities offer this comparison. Consumption exceeding the 75th percentile warrants investigation.
2. Energy audit: Professional blower door test, thermal imaging, and duct leakage test to identify specific deficiencies.
3. HVAC performance testing: Measure supply and return air temperatures across the coil (delta-T should be 15-22F for cooling). Check static pressure (should be under 0.5 in WC). Verify airflow per ton (350-450 CFM/ton).
4. Appliance energy metering: Use a plug-in meter (Kill-A-Watt) to measure actual energy consumption of major appliances. Compare to EnergyGuide ratings and to newer models.
5. Phantom load audit: Use smart plugs with energy metering on each major electronics cluster. Total always-on load exceeding 100W is a target for improvement.
6. Infrared scan: During heating season, scan exterior walls, ceilings, and floors for thermal anomalies indicating missing insulation or air leakage.

Code & Compliance

• IECC (International Energy Conservation Code): Sets minimum energy efficiency requirements for new construction and major renovations. Updated every 3 years. 2024 IECC requires approximately 50% more efficiency than 2006 IECC.
• ENERGY STAR certification: Voluntary program. New homes earning ENERGY STAR are approximately 10% more efficient than code. ENERGY STAR Version 3.2 includes HVAC, envelope, and duct testing requirements.
• DOE appliance standards: Federal minimum efficiency standards for appliances, water heaters, HVAC equipment. Updated periodically. Manufacturers must meet or exceed these minimums.
• State energy codes: Many states adopt IECC with amendments. California Title 24 is the most stringent. Washington and Vermont also have advanced codes.
• IRA incentives: Inflation Reduction Act provides tax credits (25C) for envelope improvements (up to $1,200/year), heat pumps (up to $2,000/year), and HOMES rebates for measured energy savings.
• Utility programs: Most utilities offer rebates for efficiency improvements. Check DSIRE database for local programs.

Cost Guide

| Improvement | Typical Cost | Annual Savings | Payback | |------------|-------------|----------------|---------| | Air sealing (professional) | $1,000-$2,500 | $150-$400 | 3-6 years | | Attic insulation to R-49 | $1,500-$3,000 | $100-$300 | 5-10 years | | LED conversion (30 bulbs) | $100-$300 | $150-$300 | < 1 year | | Smart thermostat | $130-$300 | $100-$200 | 1-2 years | | Heat pump water heater | $2,000-$4,000 | $200-$400 | 5-10 years | | Heat pump HVAC (ducted) | $8,000-$18,000 | $300-$800 | 10-20 years | | ENERGY STAR windows | $600-$1,200/each | $15-$30/each | 20-40 years | | Smart power strips | $20-$40 each | $30-$50/each | < 1 year | | Duct sealing | $500-$1,500 | $100-$300 | 2-5 years |

IRA tax credits (Section 25C): 30% of cost, up to $1,200/year for envelope improvements (insulation, windows, doors, air sealing) and up to $2,000/year for heat pumps (HVAC or water heater). These credits are nonrefundable (reduce your tax liability but cannot generate a refund).

HOMES rebates: Up to $2,000 for 20%+ energy reduction (modeled pathway) or up to $4,000 for 35%+ reduction. Income-qualified households eligible for double the rebate amounts. Administered by state energy offices.

Energy Impact

The average US home consumes approximately 10,500 kWh of electricity and 500 therms of natural gas per year, totaling roughly $2,000-$2,500 in energy costs.

Potential savings by category:

• Building envelope improvements: 15-25% of heating/cooling costs
• HVAC upgrade (to heat pump): 30-50% of heating/cooling costs
• Water heater upgrade (to heat pump): 50-70% of water heating costs
• LED lighting: 50-80% of lighting costs
• Phantom load elimination: 5-10% of electricity costs
• Behavioral changes: 5-15% of total energy costs

Comprehensive approach: Addressing all categories simultaneously typically yields 30-50% total energy savings, or $600-$1,250 per year. The interactive effects mean that addressing the envelope first makes the HVAC system more effective, which makes the home more comfortable, which reduces behavioral energy waste.

Zero energy potential: A highly efficient existing home (tight envelope, heat pump HVAC, heat pump water heater, LED lighting, minimal phantom loads) consumes 40-60% less energy than a typical home. This reduced load is much easier and cheaper to offset with solar panels, making net-zero energy achievable for many homes.

Shipshape Integration

Comprehensive energy dashboard: Shipshape aggregates data from utility accounts, smart thermostats, energy monitors, and solar systems to provide a complete picture of home energy performance. Homeowners see consumption broken down by category (HVAC, water heating, appliances, lighting, other) with trends over time.

Efficiency scoring: The Home Health Score's Energy subscore is based on known equipment efficiency ratings, building characteristics, energy consumption data, and maintenance currency. The score provides an at-a-glance assessment of the home's energy performance and identifies the highest-impact improvement opportunities.

Appliance tracking: Shipshape tracks the age and efficiency ratings of major appliances and systems. As equipment ages, SAM calculates the cost of continued operation vs replacement with high-efficiency alternatives and presents this data when the ROI reaches an actionable threshold.

Phantom load detection: When integrated with whole-home energy monitors, SAM identifies elevated baseline loads and recommends smart power strip strategies for the highest-waste circuits.

Rebate and incentive matching: SAM matches available utility rebates, state programs, and federal tax credits to the homeowner's specific improvement opportunities. This information is surfaced alongside ROI calculations to make upgrade decisions easier.

Cost tracking: All energy-related costs, improvements, rebates, and savings are tracked on the home dashboard. Homeowners see their energy cost trajectory and the cumulative return on efficiency investments.

Dealer actions: Service providers receive prioritized efficiency improvement recommendations for each home based on Shipshape's analysis. Recommendations include estimated costs, savings, payback periods, and applicable rebates, enabling informed conversations with homeowners.