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Month-by-month operating costs with real Eversource and United Illuminating rates. See exactly what a heat pump costs to run — and how it compares to oil, gas, and propane.
$1,773
Annual (Eversource)
$2,350
Annual (Oil)
$577
Annual Savings vs Oil
The most common question we hear from Connecticut homeowners considering a heat pump: "What will my electric bill actually be?" The answer depends on your home size, insulation, utility provider, and how cold it gets — but we can give you real numbers based on actual CT conditions.
Below is a month-by-month breakdown for a typical 2,000 square foot Connecticut home using a modern cold-climate heat pump (COP 3.0 seasonal average). We compare the monthly cost at both Eversource ($0.27/kWh) and United Illuminating ($0.28/kWh) rates, plus what you would spend on heating oil ($3.50/gallon) and natural gas ($1.85/therm) to heat the same home.
Important Assumptions
These estimates assume a properly sized cold-climate heat pump (ENERGY STAR Cold Climate certified), adequate home insulation, and the heat pump as the primary heating and cooling system. Homes with poor insulation or oversized/undersized equipment will see different results. The federal 25C energy efficiency credit expired December 31, 2025 and is NOT factored in.
Monthly electricity cost for heating and cooling combined. Oil and gas columns show heating-only cost for the same home during heating months (those fuels do not provide cooling).
| Month | Avg Temp | HP kWh | Eversource | UI | Oil | Gas | Notes |
|---|---|---|---|---|---|---|---|
| January | 27°F | 1,150 | $311 | $322 | $520 | $385 | Peak heating month. COP drops to ~2.2 at coldest temps. |
| February | 30°F | 1,020 | $275 | $286 | $460 | $340 | Heavy heating. Slightly shorter month reduces total. |
| March | 38°F | 780 | $211 | $218 | $350 | $260 | Transitional month. COP improves as temps rise. |
| April | 49°F | 380 | $103 | $106 | $170 | $130 | Light heating. System operates at high efficiency (COP 3.5+). |
| May | 59°F | 140 | $38 | $39 | — | — | Minimal load. Some heating mornings, occasional cooling. |
| June | 68°F | 250 | $68 | $70 | — | — | Cooling season begins. Very efficient operation. |
| July | 74°F | 420 | $113 | $118 | — | — | Peak cooling. SEER2 efficiency matters most here. |
| August | 72°F | 380 | $103 | $106 | — | — | Heavy cooling month. Dehumidification adds load. |
| September | 64°F | 150 | $41 | $42 | — | — | Cooling tails off. Mild temps = minimal cost. |
| October | 53°F | 260 | $70 | $73 | $115 | $90 | Heating season begins. Excellent COP at these temps. |
| November | 42°F | 620 | $167 | $174 | $280 | $210 | Moderate heating. COP around 3.0 on average. |
| December | 31°F | 1,010 | $273 | $283 | $455 | $335 | Heavy heating month. Second-highest cost after January. |
| ANNUAL TOTAL | — | 6,560 | $1,773 | $1,837 | $2,350 | $1,750 | Heating + cooling |
$577/yr
saved with heat pump
Fuel: $2,350/yr (heating only)
Heat pump: $1,773/yr (heating + cooling)
At $3.50/gallon, ~770 gallons/year
$-23/yr
saved with heat pump
Fuel: $1,750/yr (heating only)
Heat pump: $1,773/yr (heating + cooling)
At $1.85/therm, ~1,190 therms/year
$1,127/yr
saved with heat pump
Fuel: $2,900/yr (heating only)
Heat pump: $1,773/yr (heating + cooling)
At $3.82/gallon, ~760 gallons/year
Heat pump costs include both heating AND cooling. Fuel costs are heating only — add $400-$600/year for separate AC if comparing total comfort costs.
Annual heat pump operating cost compared to fossil fuel alternatives for different home sizes.
| Home Size | HP (Eversource) | HP (UI) | Heating Oil | Natural Gas | Propane | Savings vs Oil |
|---|---|---|---|---|---|---|
| 1,500 sqft | $1,347 | $1,397 | $2,025 | $1,650 | $2,175 | $678/yr |
| 2,000 sqft | $1,771 | $1,837 | $2,700 | $2,200 | $2,900 | $929/yr |
| 2,500 sqft | $2,195 | $2,276 | $3,375 | $2,750 | $3,625 | $1,180/yr |
| 3,000 sqft | $2,619 | $2,716 | $4,050 | $3,300 | $4,350 | $1,431/yr |
A heat pump does not generate heat — it moves heat from outside air into your home. This is why it produces 2-4 units of heat for every unit of electricity consumed. The Coefficient of Performance (COP) measures this efficiency.
Below 10°F
2.0-2.2
Rare in CT (5-10 days/yr)
10-30°F
2.2-2.8
Typical CT winter
30-50°F
3.0-3.5
Fall/spring heating
Above 50°F
3.5-4.5
Mild weather
At COP 3.0 (typical CT seasonal average), each kWh of electricity produces 3 kWh of heat. At Eversource rates ($0.27/kWh), the effective heating cost is $0.09/kWh of heat. Compare this to: heating oil at $0.25/kWh-equivalent, natural gas at $0.20/kWh-equivalent, and propane at $0.28/kWh-equivalent. The heat pump wins on cost even at CT's relatively high electric rates.
Set It and Forget It
Unlike furnaces, heat pumps work best at a constant temperature. Avoid large thermostat setbacks — dropping from 68°F to 60°F overnight forces the heat pump into inefficient catch-up mode.
Insulate First
Energize CT Home Energy Solutions (HES) provides a free energy audit. Air sealing and insulation can reduce heating load 20-30%, directly cutting heat pump operating costs.
Use Smart-E Financing Wisely
The Smart-E heat pump rate is 0.99% APR (through 3/31/2026). This incredibly low rate means the monthly loan payment can be less than the monthly fuel savings.
Annual Maintenance
Clean filters monthly during peak use. Annual professional service ($150-$250) maintains COP. Dirty filters can drop efficiency 10-15%, adding $180-$270/year.
Manage Defrost Cycles
Heat pumps defrost periodically in winter — this is normal. If defrost runs excessively (more than 10% of the time), have the unit inspected. Excessive defrost wastes 15-20% more electricity.
Pair with Solar
A 4-5 kW solar array can offset most of your heat pump electricity. Combined with the Energize CT rebate and RRES netting, your effective heating cost approaches $0.
Monthly costs are calculated using: 2026 Eversource CT residential rate ($0.27/kWh) and UI residential rate ($0.28/kWh), NOAA climate normals for Hartford/New Haven CT, cold-climate heat pump seasonal COP of 3.0 (ranging 2.0-4.5 by outdoor temperature), manual J heating/cooling load calculations for a moderately insulated 2,000 sqft home, heating oil at $3.50/gallon (CT EIA average, 85% AFUE), natural gas at $1.85/therm (CT residential average, 92% AFUE), and propane at $3.82/gallon (CT average, 90% AFUE). Federal 25C energy efficiency credit is $0 (expired Dec 31, 2025).
A heat pump in Connecticut costs approximately $100-$310 per month depending on the season and your utility. For a typical 2,000 sqft home: January (peak winter) costs $275-$322/month, July (peak summer) costs $113-$118/month, and shoulder months (April, October) cost $70-$106/month. Annual total ranges from $1,770-$1,840 for Eversource vs UI customers.
Yes, significantly. A heat pump costs approximately $1,770-$1,840/year for a 2,000 sqft CT home compared to $2,700/year for heating oil at $3.50/gallon. That is a savings of $860-$930/year. The heat pump also provides air conditioning, which oil cannot. Total annual savings including eliminated AC costs are even higher.
A heat pump in CT costs approximately $1,770-$1,840/year (heating + cooling) compared to approximately $2,200/year for natural gas heating alone (plus separate AC costs). The savings are more modest than oil — roughly $360-$430/year for heating only. When you include eliminated AC costs (~$400-$600/year), total savings reach $760-$1,030/year.
Eversource charges approximately $0.27/kWh while United Illuminating charges approximately $0.28/kWh. For a 2,000 sqft home, the annual heat pump operating cost difference is approximately $66 — UI customers pay $1,837 vs $1,771 for Eversource customers. This is a small difference relative to the savings over fossil fuel heating.
A heat pump heating a 2,000 sqft CT home uses approximately 1,000-1,150 kWh per month during peak winter months (December-February). This is when the Coefficient of Performance (COP) drops to around 2.2-2.5 as outdoor temperatures fall below freezing. In milder months, usage drops to 260-780 kWh. Total annual heating electricity is approximately 5,300 kWh.
In Connecticut winters, a modern cold-climate heat pump (ENERGY STAR Cold Climate certified) maintains a COP of 2.0-2.5 during the coldest periods (below 20 degrees F), rising to 3.0-3.5 in the 30-50 degrees F range. Seasonal average COP across the full heating season is approximately 2.8-3.0. This means the heat pump produces 2.8-3.0 units of heat for every unit of electricity consumed.
Modern cold-climate heat pumps (Mitsubishi Hyper-Heat, Fujitsu XLTH) operate down to -13 to -15 degrees F, which covers virtually all CT winter conditions. However, many CT homeowners keep their existing oil or gas system as emergency backup for rare extreme cold events. This "hybrid" or "dual-fuel" approach costs more upfront ($14,000-$26,000) but provides peace of mind.