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Home Energy Audit Calculator

Evaluate your home's energy efficiency and get improvement recommendations

Home Energy Audit Calculator Guide: Identify Energy Waste & Cut Bills

Assess your home's energy efficiency and get a prioritized plan to reduce consumption and costs. This guide explains what the Home Energy Audit Calculator evaluates—envelope, HVAC, water heating, lighting/appliances—and how to turn results into high-ROI upgrades. It also clarifies pro diagnostics like blower door testing (airtightness) and infrared thermography (hidden heat loss).

Overview

The calculator compiles inputs about insulation, windows/doors, air leakage, heating/cooling systems, and major appliances to generate an efficiency score and action list. Professional audits often add onsite testing—blower door to quantify leakage (ACH50) and thermal imaging to map cold bridges and missing insulation—helpful context while interpreting your results.

What We Evaluate

Building Envelope

  • Insulation (loft/attic, walls, floors, basement/crawl spaces).
  • Windows & doors (age, glazing, U-factor for insulation, SHGC for solar gain). Lower U-factor = better insulation; lower SHGC = less solar heat admitted.
  • Air leaks at rim joists, service penetrations, recessed lights, and around frames. Draught-proofing these gaps reduces heating demand while maintaining healthy ventilation.
  • Roof & siding condition affecting moisture and thermal performance.

HVAC Systems

  • Heating efficiency: furnace/boiler AFUE, heat pump HSPF2 (heating).
  • Cooling efficiency: AC/heat pump SEER2 (cooling). (Standards were updated in 2023; higher numbers = greater efficiency.)
  • Ductwork: leakage/insulation.
  • Controls: smart/programmable thermostats and zoning.

Water Heating

  • Type: storage tank, tankless, heat pump water heater, or solar thermal.
  • Efficiency metric: Uniform Energy Factor (UEF)—higher is better.
  • Usage patterns: draw profile, setpoint temperature, recirculation.

Lighting & Appliances

  • Lighting mix (LED vs CFL/incandescent).
  • Major appliances (fridge/freezer, laundry, dishwasher) and ENERGY STAR® qualifications.
  • Standby/phantom loads from electronics and always-on devices.

How to Use the Calculator

  1. Home details: year built, size, construction type, climate.
  2. Envelope: insulation R-values, window type/age, draught-proofing status.
  3. Systems: heating/cooling types and efficiencies (AFUE/SEER2/HSPF2), duct condition.
  4. Water heating: type and UEF, tank size or flow rate.
  5. Loads & habits: appliance inventory, lighting mix, thermostat setpoints.
  6. Get results: an efficiency score, priority upgrades, and an estimated payback range.

Pro tip: If you’ve had a professional audit, enter the measured ACH50 and any infrared findings for more precise recommendations. Blower door and thermography are standard in detailed assessments.

Efficiency Score (0–100)

  • 90–100: Excellent (top performers)
  • 80–89: Very good (above average)
  • 70–79: Good (typical; opportunities remain)
  • 60–69: Fair (below average; improvements needed)
  • <60: Poor (significant upgrades recommended)

(Score bands are calculator heuristics; actual savings depend on climate, energy prices, occupancy, and installation quality.)

Common Improvement Recommendations

High Impact (Quick Wins)

  • Air sealing around doors/windows; seal rim joists and penetrations.
  • Draught-proofing letterboxes, floorboards, and loft hatches (ensure adequate ventilation).
  • Thermostat optimization (smart schedules, lower hot-water setpoints).
  • LED upgrades for high-use fixtures.

Medium Impact

  • Attic/loft insulation to recommended levels; top-up or add where thin/missing.
  • Efficient appliances (ENERGY STAR where applicable).
  • Low-flow taps/showers to cut hot-water load.
  • Duct sealing & insulation if ducts run in unconditioned spaces.

Higher Investment

  • Heat pump for space conditioning (look for higher HSPF2/SEER2).
  • High-performance windows with low U-factor and climate-appropriate SHGC.
  • Heat pump water heater (higher UEF) or solar thermal.
  • Solar PV and battery where viable (pairing with electrified heating amplifies benefits).

Potential Savings (Illustrative)

| Upgrade | Typical Annual Savings* | Payback Window* | |---|---:|---:| | Targeted air sealing | $100–$200 | 1–2 yrs | | Loft/attic insulation | $200–$400 | 2–4 yrs | | HVAC replacement (to high-efficiency or heat pump) | $300–$600 | 5–10 yrs | | Window upgrades (by phase/priority) | $200–$500 | 8–15 yrs |

* Actual savings vary by energy prices, climate, occupancy, baseline condition, and installation quality. Use your calculator results and, if needed, a professional audit to refine estimates.

Professional Audit vs DIY

DIY Benefits

  • Low cost; immediate actions (sealing, LED, controls).
  • Builds literacy for informed contractor quotes.

Professional Benefits

  • Blower door (airtightness) and thermographic scan to pinpoint hidden losses.
  • Safety checks (e.g., combustion appliances), detailed reporting, and documentation for rebates/programs.

Windows: Picking the Right Metrics

  • U-factor (lower = better insulation).
  • SHGC (lower = less solar gain; ideal in hot climates; moderate in mixed).
  • Look for labels/certifications and climate-specific recommendations.

HVAC: Understanding Efficiency Labels

  • AFUE (furnaces/boilers): seasonal fuel efficiency (higher = better).
  • SEER2 (cooling) and HSPF2 (heating) for heat pumps/AC—2023+ rating procedures; compare like for like and meet regional minimums or higher for best results.

Water Heating: Why UEF Matters

  • UEF compares output to energy input over standardized draws.
  • For the same size and type, a higher UEF unit typically costs less to operate. Heat pump water heaters often lead on UEF.

Next Steps

  1. Tackle quick wins this week (sealing, LEDs, thermostat settings).
  2. Plan insulation (loft first), then address ducts/windows by priority.
  3. Price electrification options (heat pump space/water heating) with attention to HSPF2/SEER2/UEF.
  4. Check incentives (utility/government) and require proper commissioning/testing.
  5. Track bills and re-run the calculator after upgrades to validate savings.

References

  • U.S. DOE — Professional Home Energy Assessments; Blower Door Tests; Thermographic Inspections.
  • U.S. DOE — Estimating Costs & Efficiency: Water Heaters (UEF basics).
  • ENERGY STAR / U.S. DOE — Window performance (U-factor, SHGC).
  • Energy Saving Trust (UK) — Draught proofing; Reducing home heat loss (insulation guidance).
  • Trane / American Standard — 2023+ HVAC metrics (SEER2/HSPF2 overview & minimums).