Fairfield County · heating oil
Heating oil is $5.91 a gallon. Last September it was $3.17.
Connecticut’s statewide average retail price for residential No. 2 heating oil was $5.913 in the week of 21 September 2026. The same week a year earlier it was $3.175. That is +$2.74 a gallon, or about 86%, and it lands on Fairfield County harder than on most of the state, because this is where the big, old, oil-heated houses are.
Source: CT DEEP weekly Retail Heating Oil Price Survey, week of 21 Sep 2026. We update this page when DEEP publishes a materially different week, and we do not move the date otherwise.
What it does to one season
Take a 2,500–3,000 sq ft house built before 1960 — ordinary housing stock in Darien, Wilton or Ridgefield. A house like that burns somewhere around 1,200 gallons across a Connecticut winter.
Nothing about the house changed. No new draft appeared. The same leaks that cost you $3,800 last winter cost you near $7,000 this one — which is why the cheapest thing you can do this autumn is find out which part of the house is responsible before you fill the tank.
Where the money actually goes
In a pre-1960 Fairfield County house, the heat does not leave evenly. Two places dominate, and neither is the one homeowners usually blame. Windows are the famous culprit and are rarely the biggest one.
- The attic plane— warm air rises and leaves through the top of the house. In pre-1940 stock this is typically the single largest share of the loss.
- Air leakage— the gaps: rim joists, chases, around chimneys, attic hatches. Invisible, unglamorous, and usually the cheapest thing to fix per dollar saved.
- Walls, windows, basement — real, but a smaller share, and far more expensive per dollar of heat saved. Replacing windows first is the classic expensive mistake.
Calora’s free report estimates all five for your specific house from its year, size and fuel, and puts a dollar figure on each so you can see the order to fix them in. Every assumption behind it is listed on our sources page.
Why Fairfield County feels this most
Oil heat is not spread evenly across the county. Some towns are mostly on gas; others never got the mains. These six ZIPs hold the most oil-heated homes, from US Census figures — 36,783 oil-heated homes across the fifteen ZIPs we cover.
| Town | ZIP | Oil-heated homes | Share on oil |
|---|---|---|---|
| Ridgefield | 06877 | 5,649 | 61% |
| Darien | 06820 | 4,616 | 64% |
| Westport | 06880 | 4,588 | 47% |
| New Canaan | 06840 | 4,474 | 63% |
| Wilton | 06897 | 4,441 | 73% |
| Fairfield | 06824 | 3,089 | 26% |
US Census ACS 2024 5-year, table B25040. All fifteen ZIPs and the exact tables.
Your options this winter, honestly
There are three real ways to find out where your heat is going, and ours is not always the right one.
Energize CT / Eversource Home Energy Solutions — $40
A technician visits, runs a blower-door test, and does air sealing on the spot — free for up to seven hours of work. As of 1 April 2026 the visit carries a $40 copay. You need to be an Eversource, UI, CNG or SCG customer, your home must not have had the service in six years, and there may be a waiting list. If you qualify and can wait, this is the best value in Connecticut and you should book it. Households at or below 60% of state median income pay nothing at all.
An independent energy audit — roughly $300–$600
A RESNET or BPI-certified auditor, paid out of pocket, with no utility paperwork and no eligibility rules. The most thorough option and the most expensive. Worth it before a large retrofit where you want measured numbers rather than estimates.
Calora’s free heat-loss report — free, about ninety seconds
Three questions about your house, and an estimate on screen of which part is losing the most and roughly what it costs a year. No copay, no utility account, no visit, no obligation. It is an estimate, not a measurement — built from your house’s year, size and fuel against county housing-stock data, and we round every figure down. Use it to know where to look and what to ask for; use one of the two options above when you need the real numbers off a meter.
Calora is built and run end to end by AI agents on NanoCorp, which is why we can re-check the oil price against the state’s own weekly survey and correct this page the week it moves.
Find out about your house
Enter your ZIP. Three questions, then your report. Free, and we never charge a homeowner anything.
A heating or insulation contractor? See which Fairfield County ZIPs are unsold.